ACUS01 KWNS 051951
SWODY1
SPC AC 051949

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0249 PM CDT Mon May 05 2025

Valid 052000Z - 061200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
SOUTHERN PLAINS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE UPPER
OHIO VALLEY/MID-ATLANTIC...AND PARTS OF THE EASTERN FLORIDA
PENINSULA...

...SUMMARY...
Severe thunderstorms are expected across southeast New Mexico into
Texas this afternoon into tonight. Scattered large to very large
hail and severe winds are the primary threats, though a few
tornadoes are also possible. Additional strong to severe
thunderstorms should occur across the upper Ohio Valley/Mid-Atlantic
and the eastern Florida Peninsula this afternoon and evening.

...20z Update...
Minor adjustments were made to the D1 Outlook to extend the Slight
Risk further south and east across portions of south-central Texas
near the Houston Metro. A persistent supercell has been shifting
south and east along a boundary of more favorable CAPE, producing
large hail. Additional thunderstorms may traverse this region
through the afternoon/evening posing some risk for severe wind and
hail.

Additional development across portions of western Texas and
southeastern New Mexico is expected to intensify late
afternoon/evening. The Slight was expanded northwestward to account
for latest trends in storm development. See MCD#696 for more
information.

See previous discussion below for more information.

..Thornton/Gleason.. 05/05/2025

.PREV DISCUSSION... /ISSUED 1130 AM CDT Mon May 05 2025/

...Southern Plains...
Generally elevated convection is ongoing late this morning from
portions of northwest to south-central TX. This activity is largely
being driven by low-level warm/moist advection atop a surface front.
Given the presence of steep mid-level lapse rates and strong
effective bulk shear, some of these thunderstorms should continue to
pose a threat for mainly isolated large hail in the short term. If
the convection across south-central TX can persist through the
afternoon, it will have some chance to become surface based and pose
a greater threat for hail, damaging winds, and perhaps a tornado
with eastward extent towards the Gulf Coast, as the surface front
attempts to lift slowly northward. Severe probabilities have been
expanded eastward some to account for this potential.

Farther west, a closed mid/upper-level low will move slowly eastward
across the Southwest through the period. Difluent flow aloft will
encourage weak lee cyclogenesis across far west TX through this
evening, and low-level moisture will continue to stream
northwestward along/south of a front across south-central/west TX
into southeast NM. Moderate to locally strong instability will
likely be in place by late afternoon along/east of a surface dryline
across far west TX, and south of the front. There is still a fair
amount of uncertainty regarding the timing of robust convective
initiation across the southern High Plains, as stronger mid-level
height falls/ascent attendant to the upper low begin to overspread
the warm sector mainly this evening.

Even with this continued uncertainty, it appears likely that several
supercells will erupt by no later than this evening across southeast
NM into parts of west and south-central TX. Given a rather favorable thermodynamic and kinematic environment, along with steep mid-level
lapse rates, very large hail will be a concern with these
supercells. A strengthening southeasterly low-level jet through the
evening will also act to increase low-level shear and provide
enhanced boundary-layer hodograph curvature/elongation. The threat
for a few tornadoes with any sustained supercell remains apparent.
The potential for convection to grow upscale into one or more
clusters this evening/overnight remains uncertain. Still, some
threat for severe winds will exist with any supercell or clusters.
Based on latest guidance trends, the Enhanced Risk has been expanded southeastward towards Del Rio.

...Upper Ohio Valley/Mid-Atlantic to Eastern North Carolina...
A closed upper low will remain centered over the OH Valley today. A
mid-level shortwave trough and attendant jet is forecast to move
northward from the Carolinas to the southern Mid-Atlantic through
the afternoon and evening. Large-scale ascent will likely encourage
scattered thunderstorms to form generally along and west of a
surface front that arcs from southeast VA to western/central PA.
Daytime heating of a modestly moist low-level airmass and cool
temperatures aloft associated with the upper low should aid in the
development of around 500-1500 J/kg of MLCAPE by mid afternoon
across parts of the upper OH Valley into the southern Mid-Atlantic
and eastern NC. Even though low-level flow will tend to remain
fairly muted, southeasterly winds near the surface are forecast to
gradually veer to southerly and strengthen with height at mid/upper
levels. This should support sufficient deep-layer shear for
organized convection. A mix of multicells and supercells are
anticipated, with a threat for scattered large hail and damaging
winds as they spread northward through the afternoon and evening.
Based on latest observational and guidance trends, some westward and
southward expansions have been made to the Slight Risk across these
regions.

...Florida Peninsula...
Much of the FL Peninsula will remain displaced south of the stronger mid/upper-level flow and forcing associated with an upper low over
the OH Valley today. Still, seasonably cool temperatures aloft
combined with modest enhancement to the mid-level westerlies should
foster adequate instability and deep-layer shear to support modest
updraft organization. Thunderstorms are expected to preferentially
favor the Atlantic Coast sea breeze today, with a stalled front over
the central FL Peninsula also serving as a potential low-level
forcing mechanism. Any convection which does develop may pose a
threat for severe hail and damaging winds before it moves offshore
by early evening. Given increased confidence in scattered to
numerous thunderstorms, along with long/straight hodographs aloft, a
Slight Risk for hail has been added for parts of the eastern FL
Peninsula with this update.

...Western Dakotas...
Even with low-level moisture remaining limited across the northern
Plains today, weak instability should develop by this afternoon in a
narrow zone focused along a front extending across the western
Dakotas. Widely scattered thunderstorms should initiate along this
boundary by this afternoon as glancing large-scale ascent from a
shortwave trough over the Canadian Prairie provinces overspreads the
region. A well-mixed boundary layer and steep lapse rates should
promote efficient momentum transfer with downdrafts, and isolated
strong to severe winds and perhaps some hail may occur with
pulse-type and loosely organized clusters.

$$

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ACUS01 KWNS 060102
SWODY1
SPC AC 060101

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0801 PM CDT Mon May 05 2025

Valid 060100Z - 061200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
FAR SOUTHEAST NEW MEXICO AND WEST TEXAS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS AND MID-ATLANTIC...

...SUMMARY...
Severe thunderstorms, potentially with very large hail and wind
gusts exceeding 70 mph, are expected this evening into tonight
across parts of the southern High Plains. Isolated severe storms
will also be possible in parts of the Mid Atlantic, central
Appalachians, Dakotas and Florida.

...Southern High Plains...
According to water vapor imagery, a mid-level low is located over
the Desert Southwest. Ahead of the low, southwesterly divergent flow
is present over the southern High Plains. Multiple low-amplitude
shortwave troughs appear to be moving through the flow. One is
analyzed from southeast New Mexico into West Texas. Large-scale
ascent ahead of this feature is likely supporting scattered
thunderstorm development this evening to the southwest and south of
Lubbock. Surface analysis has an inverted trough from west Texas
into south-central New Mexico. A quasi-stationary front is analyzed
from near the trough southeastward into West Texas. A corridor of
low-level moisture is analyzed to the east of the front, where
surface dewpoints are in the mid 50s to near 60 F. MLCAPE along the
moist axis is estimated to be in the 1000 to 2000 J/kg range by the
RAP. The storms are developing near the instability axis along a
zone of strong low-level convergence. Isolated storms are also
developing toward the east away from the boundary, likely in
response to warm advection and large-scale ascent.

The 00Z sounding at Midland, Texas is located near the instability
axis and shows a supercell wind profile, with 0-6 km shear near 75
knots and directional shear in the low-levels. In addition, RAP
forecast soundings in this vicinity have 700-500 mb lapse rates near
8 C/km. This environment will continue to be favorable for large
hail with the stronger rotating storms. Hailstones of greater than 2
inches in diameter will be possible within the more intense cores.
Supercells and short intense line segments will also be capable of
severe wind gusts. A few gusts over 70 mph will be possible. An
isolated tornado threat is also expected. The severe threat may
increase toward mid to late evening, as the low-level jet ramps up
across West Texas. A potential for severe storms will continue into
the overnight period, as an MCS develops and organizes. The severe
threat could affect parts of south-central Texas later tonight as
the MCS moves eastward.

...Mid-Atlantic...
Water vapor imagery shows a mid-level low over the Ohio Valley.
South to southwesterly mid-level flow is located over the Carolinas
and Mid-Atlantic. At the surface, a quasi-stationary front is
analyzed from eastern North Carolina into Maryland and southwestern Pennsylvania. Near the front, thunderstorms are ongoing with some
being strong. Along and near the front, surface dewpoints are in the
lower 60s F and MLCAPE is estimated from 500 to 1000 J/kg. RAP
forecast soundings near the front this evening show moderate
deep-layer shear, which should support an isolated severe threat
over the next couple of hours. Severe gusts and hail will be the
primary threats, with the greatest threat located from western
Maryland into eastern Virginia, where the combination of instability
and shear is maximized, according to the RAP.

...Dakotas...
Surface analysis shows a 1007 mb low over northern South Dakota near
a quasi-stationary front. This boundary extends from western South
Dakota northeastward across central North Dakota. Near the front,
the RAP has MLCAPE from 1000 to 2000 J/kg. Scattered thunderstorms
are ongoing near the instability axis. Although shear is marginal
for severe storms, lapse are steep. This could be enough for hail
and isolated severe gusts over the next couple of hours.

...Florida...
Scattered thunderstorms are currently ongoing across the eastern
part of the Florida Peninsula. The convection first developed in
response to low-level convergence along a sea breeze boundary, and
is likely being supported by a subtle shortwave trough, evident on
water vapor imagery and on RAP analysis. Across eastern Florida, the
RAP has moderate instability and 0-6 km shear near 35 knots. This
environment should support an isolated severe threat over the next
hour or two. Steep low-level lapse rates will likely be sufficient
for marginally severe gusts with a few of the storms.

..Broyles.. 05/06/2025

$$

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ACUS01 KWNS 060602
SWODY1
SPC AC 060600

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Tue May 06 2025

Valid 061200Z - 071200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHEAST TEXAS...

...SUMMARY...
Severe thunderstorms are likely today across parts of the southern
Plains into the Lower Mississippi Valley. Some storms will be
capable of producing severe gusts, large to very large hail, and
tornadoes. Strong tornadoes will be possible. Isolated strong to
severe storms with hail and marginally severe gusts may also occur
in the northern Mid-Atlantic.

...Southern Plains/Lower Mississippi Valley...
At mid-levels, a low will move into the southern Rockies today, as
an associated 60 to 70 knot jet streak translates northeastward
across the southern Plains. Within the exit region of the jet,
scattered thunderstorms are expected to be ongoing in west Texas at
the start of the period, along the western edge of a moist airmass.
The moist airmass will be located over much of the eastern half of
Texas extending eastward into the lower Mississippi Valley.
Scattered to numerous thunderstorms are expected to develop around
midday from north-central Texas into southern Oklahoma, in
association with warm advection. A severe threat is expected to
develop with this convection, and should increase during the
afternoon. In areas that heat up, supercells with large hail and
severe gusts will be possible. Hailstones of greater than 2 inches
in diameter may occur with the more intense supercell updrafts,
mainly in northwest and central Texas where mid-level lapse rates
are forecast to be steep.

Further to the southeast, the airmass is likely to remain
undisturbed through midday. A warm front will move slowly northward
across central and southeast Texas. From this front southward,
surface dewpoints will likely be from the upper 60s to mid 70s F. As
surface temperatures warm during the day, strong instability is
forecast to develop. The models are in reasonably good agreement
that MLCAPE will peak between 3000 and 4000 J/kg during the
afternoon. In addition, the mid-level jet will move into the
southern Plains, creating strong deep-layer shear favorable for
supercells. In response, a 40 to 50 knot low-level jet is forecast
to develop across southeast Texas. Forecast soundings to the
northwest of the Houston area increase 0-3 km storm-relative
helicity into the 350 to 400 m2/s2 range. This shear environment
will be favorable for supercells and tornadoes. A few strong
tornadoes will be possible within parts of the airmass that heat up
the most and remain undisturbed into the early afternoon. MCS
development appears likely during the afternoon across east Texas.
Rotating storms within the MCS will be capable of large hail and
severe gusts. This threat should spread eastward into the lower
Mississippi Valley during the late afternoon and early evening.

...Northern Mid-Atlantic...
A mid-level low will move northeastward across the Ohio Valley
today, as a front advances eastward through the central Appalachians
into the Mid-Atlantic. An axis of low-level moisture will be located
ahead of the front with surface dewpoints in the 50s F. As surface
temperatures heat up during the day, weak instability is forecast to
develop along and near this moist axis. Low-level convergence and
large-scale ascent associated with the mid-level system will likely
support isolated to scattered thunderstorm development. In addition
to the weak instability, RAP forecast soundings have moderate
deep-layer shear in the Mid-Atlantic with steep low-level lapse
rates exceeding 8 C/km. This could support a marginal wind-damage
threat during the afternoon, with the threat eventually
transitioning eastward into the Hudson River Valley.

..Broyles/Moore.. 05/06/2025

$$

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ACUS01 KWNS 061256
SWODY1
SPC AC 061254

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 AM CDT Tue May 06 2025

Valid 061300Z - 071200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL
AND EAST/SOUTHEAST TEXAS TO WESTERN LOUISIANA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHEAST...

...SUMMARY...
Severe thunderstorms are expected today into this evening especially
across central into east/southeast Texas into Louisiana. Large to
very large hail, damaging winds, and tornadoes, potentially a few of
which may be strong, can be expected. Severe storms may also occur
across parts of the Northeast and the Florida Peninsula.

...Southern Plains/Lower Mississippi Valley...
Strengthening cyclonic southwesterly flow aloft/mid-level jet streak
will overspread an increasingly moist boundary layer that will exist along/north of a northward-shifting warm front across central/east
Texas into Louisiana. Of primary concern is potential supercell
development near the warm front and just ahead of the surface wave,
which could materialize relatively early today. Ample
deep-layer/low-level shear will support the supercell potential with
risks for large to very large hail, damaging winds, as well as
tornadoes, including strong tornado potential. This will be in the
presence of upwards of 2500-4000 J/kg MLCAPE and 40-55 kt effective
shear, with low-level SRH maximized in the
east/northeastward-transitioning low-level jet axis and in proximity
to the warm front. Other more elevated storms are expected north of
the warm front, with large hail most common, but some wind potential
as well even with slightly elevated storms. A mixed mode of storms
including embedded supercells and MCS development/persistence is
expected into Louisiana by evening.

...Northern Mid-Atlantic/Northeast States...
Storm development and intensification is expected today within a
modestly moist/unstable air mass preceding the upper low over the
upper Ohio River Valley. Relatively steep lapse rates and moderately
strong deep-layer south-southwesterly flow will influence some
potentially organized storms capable of severe hail and damaging
winds, particularly across eastern Pennsylvania, New Jersey and the
Delmarva vicinity near the surface triple point, where the
combination of ingredients appear most favorable for severe storms.

...Florida...
While the upper ridge will be more of an influence today, it seems
that residually cool temperatures aloft and moderate instability
could support at least a few locally severe storms capable of hail
and/or localized wind damage this afternoon across parts of the eastern/interior Peninsula.

..Guyer/Dean.. 05/06/2025

$$

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ACUS01 KWNS 061632
SWODY1
SPC AC 061630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Tue May 06 2025

Valid 061630Z - 071200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL
AND EAST/SOUTHEAST TEXAS TO WESTERN LOUISIANA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN MID-ATLANTIC/NORTHEAST...

...SUMMARY...
Severe thunderstorms are expected today into this evening,
especially across parts of central into east/southeast Texas and
Louisiana. Large to very large hail, damaging winds, and tornadoes,
potentially a few of which may be strong, should occur. Severe
thunderstorms may also develop this afternoon across parts of the
northern Mid-Atlantic/Northeast and the Florida Peninsula.

...Southern Plains into the Lower Mississippi Valley...
Multiple supercells are ongoing late this morning across central TX
along/near a surface warm front. As an upper trough/low continues to
eject eastward over the southern Plains today, a rather favorable
environment will be in place this afternoon and evening for intense
severe thunderstorms across central/east-central TX into LA. Even
with continued cloudiness across the warm sector, filtered daytime
heating and the presence of modestly steep mid-level lapse rates
will support moderate to locally strong instability given the
rich/moist low-level airmass present. Ample low-level and deep-layer
shear will foster continued updraft organization, including the
potential for several supercells. The greatest potential for
tornadoes, some of which could be strong, will likely remain focused
along/near the warm front, which will attempt to lift northward some
across east TX and LA through the afternoon and evening. Otherwise,
large hail will be possible north of the warm front with elevated
supercells. A severe/damaging wind threat will exist with any
clusters that can become established.

The tornado and damaging wind threat will probably continue through
the evening and perhaps overnight hours across parts of the lower MS
Valley, given sufficient instability and strong low-level shear
along/near the warm front. Have therefore adjusted the Slight Risk
eastward some across this region. Have also trimmed the Slight Risk
from the southern High Plains, as low-topped convection closer to
the cold-core upper low will probably only have access to weak
instability this afternoon/evening. Still, this activity may have an
isolated hail/wind threat, and the Marginal Risk has been maintained
across the southern High Plains for this potential.

...Northern Mid-Atlantic/Northeast...
Even in the presence of some cloud cover, thunderstorm development
and intensification will occur this afternoon across parts of the
northern Mid-Atlantic and vicinity in a modestly moist/unstable air
mass preceding an upper low over the upper OH Valley. Relatively
steep lapse rates aloft and moderate to strong deep-layer
south-southwesterly flow should support organized convection capable
of severe hail and damaging winds. The best severe threat should
remain focused across parts of eastern PA into NJ and southern NY,
where the Slight Risk has been maintained with only small
expansions.

...Florida...
Upper ridging should be more influential today over FL compared to
yesterday. Still, cool temperatures aloft and moderate instability
could support occasionally strong to severe thunderstorms capable of
producing isolated hail and/or damaging winds this afternoon across
parts of the FL Peninsula along/south of a remnant front.

..Gleason/Squitieri.. 05/06/2025

$$

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ACUS01 KWNS 062002
SWODY1
SPC AC 062000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Tue May 06 2025

Valid 062000Z - 071200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EAST/SOUTHEAST TEXAS INTO WESTERN LOUISIANA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN MID-ATLANTIC/NORTHEAST...

...SUMMARY...
Severe thunderstorms are expected today into this evening,
especially across parts of east/southeast Texas and Louisiana. Large
hail, damaging winds, and tornadoes, potentially a few of which may
be strong, are expected. Severe thunderstorms are also expected this
afternoon across parts of the northern Mid-Atlantic/Northeast and
the Florida Peninsula.

...20Z Update...
The primary change with this update was trimming severe
probabilities behind a squall line tracking eastward across parts of east/southeast Texas. A separate area of severe hail/wind
probabilities were maintained and expanded slightly over the
southern High Plains -- closer to the cold-core upper low. See MCD
#720 for details on the severe risk here. Farther south, guidance
continues to suggest an uptick in severe-thunderstorm potential
across south TX during the overnight hours. While steep lapse rates
atop rich boundary-layer moisture would conditionally support a
couple supercells capable of producing large hail and severe winds,
the overall threat appears too conditional for higher probabilities
at this time.

..Weinman.. 05/06/2025

.PREV DISCUSSION... /ISSUED 1130 AM CDT Tue May 06 2025/

...Southern Plains into the Lower Mississippi Valley...
Multiple supercells are ongoing late this morning across central TX
along/near a surface warm front. As an upper trough/low continues to
eject eastward over the southern Plains today, a rather favorable
environment will be in place this afternoon and evening for intense
severe thunderstorms across central/east-central TX into LA. Even
with continued cloudiness across the warm sector, filtered daytime
heating and the presence of modestly steep mid-level lapse rates
will support moderate to locally strong instability given the
rich/moist low-level airmass present. Ample low-level and deep-layer
shear will foster continued updraft organization, including the
potential for several supercells. The greatest potential for
tornadoes, some of which could be strong, will likely remain focused
along/near the warm front, which will attempt to lift northward some
across east TX and LA through the afternoon and evening. Otherwise,
large hail will be possible north of the warm front with elevated
supercells. A severe/damaging wind threat will exist with any
clusters that can become established.

The tornado and damaging wind threat will probably continue through
the evening and perhaps overnight hours across parts of the lower MS
Valley, given sufficient instability and strong low-level shear
along/near the warm front. Have therefore adjusted the Slight Risk
eastward some across this region. Have also trimmed the Slight Risk
from the southern High Plains, as low-topped convection closer to
the cold-core upper low will probably only have access to weak
instability this afternoon/evening. Still, this activity may have an
isolated hail/wind threat, and the Marginal Risk has been maintained
across the southern High Plains for this potential.

...Northern Mid-Atlantic/Northeast...
Even in the presence of some cloud cover, thunderstorm development
and intensification will occur this afternoon across parts of the
northern Mid-Atlantic and vicinity in a modestly moist/unstable air
mass preceding an upper low over the upper OH Valley. Relatively
steep lapse rates aloft and moderate to strong deep-layer
south-southwesterly flow should support organized convection capable
of severe hail and damaging winds. The best severe threat should
remain focused across parts of eastern PA into NJ and southern NY,
where the Slight Risk has been maintained with only small
expansions.

...Florida...
Upper ridging should be more influential today over FL compared to
yesterday. Still, cool temperatures aloft and moderate instability
could support occasionally strong to severe thunderstorms capable of
producing isolated hail and/or damaging winds this afternoon across
parts of the FL Peninsula along/south of a remnant front.

$$

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ACUS01 KWNS 070053
SWODY1
SPC AC 070052

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 PM CDT Tue May 06 2025

Valid 070100Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTH TEXAS...THE TEXAS COASTAL PLAIN...SABINE RIVER VALLEY...LOWER
MISSISSIPPI VALLEY...

...SUMMARY...
Severe storms, associated with large hail, severe gusts and an
isolated tornado threat, will be possible across parts of the Texas
Coastal Plain, Sabine River Valley and lower Mississippi Valley this
evening. Marginally severe hail will also be possible in parts of
west Texas.

...Texas Coastal Plain/Sabine River Valley/Lower Mississippi
Valley...
Latest surface analysis shows a cold front across the Texas Coastal
Plain, along which a broken line of strong thunderstorms is ongoing.
An MCS is located from east Texas eastward across much of Louisiana,
along and near a warm front. The MCS is being supported by
large-scale ascent associated with a shortwave trough, evident on
water vapor imagery over the Ark-La-Tex and lower Mississippi
Valley. The storms are also being supported by warm advection from
southern Louisiana into far southern Mississippi, where the RAP has
MLCAPE in the 1000 to 2000 J/kg range. The MCS will continue to move
eastward across this unstable airmass this evening. Within the MCS,
rotating storms should be capable of producing large hail and wind
damage. In addition, the Lake Charles, Louisiana 00Z Sounding has
0-3 km storm-relative helicity near 500 m2/s2. This will support an
isolated tornado threat with supercells that remain strong this
evening.

Further southwest from the Texas Coastal Plain into south Texas, a
very moist and unstable airmass will reside this evening. In south
Texas, the RAP suggests that MLCAPE is as great as 4500 J/kg. The
strong instability is reflected on the 00Z sounding at Brownsville,
Texas, where 0-6 km shear is near 50 knots, and the 700-500 mb lapse
rate is near 8 C/km. This environment will support supercell
development later this evening into the overnight period as a subtle
shortwave trough moves into the region. Isolated large hail and
severe gusts will be possible.

...West Texas...
A mid-level low is currently evident on water vapor imagery across
eastern New Mexico. A trough extends southeastward from the low
across west and north Texas. The trough is supporting thunderstorm
storm development along and near an axis of instability. The RAP is
estimating MLCAPE in the 500 to 750 J/kg range over parts of the
Caprock near Lubbock. In addition, the Lubbock WSR-88D VWP has 0-6
km shear near 45 knots. RAP forecast soundings early this evening
near Lubbock have steep low to mid-level lapse rates in the 7 to 8
C/km range. This environment should support a marginal threat for
hail and severe gusts over the next hour or two.

..Broyles.. 05/07/2025

$$

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ACUS01 KWNS 070519
SWODY1
SPC AC 070517

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1217 AM CDT Wed May 07 2025

Valid 071200Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE TEXAS COASTAL PLAIN...

...SUMMARY...
Isolated severe storms with large hail and wind damage will be
possible across parts of the Texas Coastal Plain. Marginally severe
storms will also be possible in parts of the southern Plains,
Ark-La-Tex and from the Sabine River Valley to the central Gulf
Coast.

...Texas Coastal Plain...
Mid-level flow will remain west-southwesterly today across the
southern Plains. At the surface, a moist airmass will be located
across the Texas Coastal Plain, where surface dewpoints will range
from the mid 60s to the lower 70s F. The airmass will be moderately
unstable throughout the day as onshore easterly flow keeps the
moisture in place. Although low-level convergence will be weak
across this airmass, isolated thunderstorms could develop in the
afternoon as minor mid-level perturbations pass through the flow.
RAP forecast soundings between San Antonio and Corpus Christi have
MLCAPE peaking near 3000 J/kg, with 0-6 km shear in the 40 to 50
knot range. 700-500 mb lapse rates are forecast to be near 7 C/km.
This could be enough for isolated large hail with cells that develop
during the mid to late afternoon. A few marginally severe wind gusts
will also be possible.

...Southern Plains/Ark-La-Tex...
A mid-level low will move eastward across the central Plains today,
as west-southwesterly flow remains in place across the southern
Plains. To the southeast of the low, a moist and unstable airmass
will be in place from east Texas northward into eastern Oklahoma and
western Arkansas. Surface heating and large-scale ascent will likely
support scattered thunderstorm development during the afternoon. RAP
forecast soundings across eastern Oklahoma at 21Z have 0-6 km shear
near 50 knots, with steep low-level lapse rates exceeding 7 C/km.
This, combined with relatively cold mid-level temperatures of -16C
to -18C, could be enough for hail. Marginally severe gusts will also
be possible.

...Sabine River Valley/Central Gulf Coast...
Thunderstorms, with some potentially strong, are forecast to be
ongoing at the start of the period from the northwest Gulf
east-northeastward into the central Gulf Coast states. This
convection is forecast to become an organized line segment, moving
eastward across the northern Gulf from this morning into the
afternoon. The northern edge of this line segment may affect areas
near the coasts of Louisiana, Mississippi, Alabama and western
Florida. Instability and steep low-level lapse rates may support a
marginal potential for severe gusts.

..Broyles/Moore.. 05/07/2025

$$

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ACUS01 KWNS 071254
SWODY1
SPC AC 071252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Wed May 07 2025

Valid 071300Z - 081200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS...OZARKS...GULF COAST...

...SUMMARY...
Isolated severe storms may occur today across parts of the southern
Plains and Ozarks to the Gulf Coast.

...Coastal/south-central Texas to middle Gulf Coast...
A cluster of previously severe storms (overnight) across Deep South
Texas is now over the western Gulf, with substantial effective-boundary-reinforcing elevated convection spanning the
upper Texas coast to coastal Louisiana and the Mobile Bay vicinity.
The more intense convection should focus offshore today, but areas
along the immediate coast, such as southern Louisiana, may have some
lingering severe risk pending the disposition of existing early day
outflow and convection, ahead of what will likely be an
upscale-growing MCS over the northwest to north-central Gulf.

Farther to the west, considerable uncertainty exists with later-day
deep convective potential across south-central/southeast Texas given
the impacts of the overnight storms, with ramifications on lapse
rates, source region moisture etc., even with a nearly full diurnal
cycle for potential air mass adjustments/recovery. These
thermodynamic trends are also in the context of weak height rises
and larger-scale subsidence regionally. While some severe storms
could develop later today into peak heating under a more optimistic airmass-recovery scenario, any such severe potential would likely
remain isolated and marginal overall.

...Southern Plains to Ozarks/Ark-La-Tex..
The mid/upper-level low will progress eastward from the
south-central Plains toward the Ozarks/Lower Missouri Valley by
tonight, accompanied by a 50+ kt belt of west-southwesterly
mid-level winds on its southern periphery. Only a subtle surface
low/features and weak convergence will exist, but weak inhibition is
expected by afternoon as cloud breaks occur under the mid-level cool
pocket (-13C to -18C at 500mb), with upwards of 500-800 J/kg MLCAPE
plausible. Some of the semi-lower-topped storms could be strong or
locally severe with hail and wind gusts possible from mid/late
afternoon into this evening, and funnel/brief tornado potential
might also diurnally exist given ambient vorticity/steep lapse rates
in proximity to the upper low.

..Guyer/Dean.. 05/07/2025

$$

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ACUS01 KWNS 071630
SWODY1
SPC AC 071628

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Wed May 07 2025

Valid 071630Z - 081200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL/EASTERN OKLAHOMA INTO WESTERN ARKANSAS AND THE OZARKS...THE
CENTRAL GULF COAST...AND SOUTHEAST GEORGIA INTO PORTIONS OF
FLORIDA...

...SUMMARY...
Isolated severe thunderstorms may occur today across parts of the
southern Plains and Ozarks, the central Gulf Coast, and separately
over southeast Georgia into portions of Florida.

...Texas to the Central Gulf Coast...
Extensive convection and related outflow has shunted greater
low-level moisture and an effective front off most of the TX Coast
this morning. Ongoing clusters/supercells just south of the LA Coast
are generally expected to remain offshore this afternoon as they
track eastward along/near the surface boundary. A small and somewhat
separate cluster with a history of producing measured severe winds
near New Orleans should track along/near the MS/AL Coast over the
next few hours while weakening, as it will remain north of the
outflow boundary/front. Even so, modest heating of a residually
moist low-level airmass may support weak MUCAPE and an isolated
threat for damaging winds and perhaps a tornado with this activity.

The potential for renewed convective development this afternoon
across TX appears low, as the upper low over OK moves northeastward
towards the Ozarks. Neutral to weakly rising mid-level heights
suggest nebulous large-scale forcing at best, and perhaps some
subsidence through the day. While a strong thunderstorm or two may
still develop across south-central TX and vicinity near the stalled
front, the overall severe potential appears too low/conditional to
maintain even Marginal Risk caliber severe probabilities with this
update.

...Central/Eastern Oklahoma into Western Arkansas...
A mid/upper-level low over KS/OK will progress eastward to the
Ozarks/Lower MO Valley by tonight, accompanied by a belt of enhanced west-southwesterly mid-level winds on its southern periphery. A weak
surface low and modest low-level convergence will exist this
afternoon across central/eastern OK. But, weak instability is still
expected to develop as cloud breaks occur under the mid-level cool
pocket (around -13 to -18 C at 500mb), with around 500-800 J/kg
MLCAPE plausible with peak afternoon heating. Some of the
lower-topped convection that develops could become strong to locally
severe with hail possible from mid/late afternoon into this evening.
Brief funnel/tornado potential may also diurnally exist given
ambient low-level vorticity/steep lapse rates in proximity to the
upper low. This activity is expected to quickly weaken with eastward
extent this evening with the loss of daytime heating.

...Florida/Coastal Georgia...
Isolated strong to severe thunderstorms may develop this afternoon
and early evening along and south of a front draped across
coastal/southeast GA into parts of FL. Moderate instability and
sufficient deep-layer shear should be present across these regions
to support some updraft organization. Occasional severe hail and
damaging winds may occur with the strongest cores.

..Gleason/Squitieri.. 05/07/2025

$$

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ACUS01 KWNS 071951
SWODY1
SPC AC 071950

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0250 PM CDT Wed May 07 2025

Valid 072000Z - 081200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL/EASTERN OKLAHOMA INTO WESTERN ARKANSAS AND THE OZARKS...AND
SOUTHEAST GEORGIA INTO PARTS OF FLORIDA...

...SUMMARY...
Isolated severe thunderstorms may occur today across parts of the
southern Plains into the Ozarks, and separately over southeast
Georgia into portions of Florida.

...20Z Update...
The primary change with this update was the removal of
severe-thunderstorm probabilities over the central Gulf Coast --
where a remnant MCS has moved offshore.

..Weinman.. 05/07/2025

.PREV DISCUSSION... /ISSUED 1128 AM CDT Wed May 07 2025/

...Texas to the Central Gulf Coast...
Extensive convection and related outflow has shunted greater
low-level moisture and an effective front off most of the TX Coast
this morning. Ongoing clusters/supercells just south of the LA Coast
are generally expected to remain offshore this afternoon as they
track eastward along/near the surface boundary. A small and somewhat
separate cluster with a history of producing measured severe winds
near New Orleans should track along/near the MS/AL Coast over the
next few hours while weakening, as it will remain north of the
outflow boundary/front. Even so, modest heating of a residually
moist low-level airmass may support weak MUCAPE and an isolated
threat for damaging winds and perhaps a tornado with this activity.

The potential for renewed convective development this afternoon
across TX appears low, as the upper low over OK moves northeastward
towards the Ozarks. Neutral to weakly rising mid-level heights
suggest nebulous large-scale forcing at best, and perhaps some
subsidence through the day. While a strong thunderstorm or two may
still develop across south-central TX and vicinity near the stalled
front, the overall severe potential appears too low/conditional to
maintain even Marginal Risk caliber severe probabilities with this
update.

...Central/Eastern Oklahoma into Western Arkansas...
A mid/upper-level low over KS/OK will progress eastward to the
Ozarks/Lower MO Valley by tonight, accompanied by a belt of enhanced west-southwesterly mid-level winds on its southern periphery. A weak
surface low and modest low-level convergence will exist this
afternoon across central/eastern OK. But, weak instability is still
expected to develop as cloud breaks occur under the mid-level cool
pocket (around -13 to -18 C at 500mb), with around 500-800 J/kg
MLCAPE plausible with peak afternoon heating. Some of the
lower-topped convection that develops could become strong to locally
severe with hail possible from mid/late afternoon into this evening.
Brief funnel/tornado potential may also diurnally exist given
ambient low-level vorticity/steep lapse rates in proximity to the
upper low. This activity is expected to quickly weaken with eastward
extent this evening with the loss of daytime heating.

...Florida/Coastal Georgia...
Isolated strong to severe thunderstorms may develop this afternoon
and early evening along and south of a front draped across
coastal/southeast GA into parts of FL. Moderate instability and
sufficient deep-layer shear should be present across these regions
to support some updraft organization. Occasional severe hail and
damaging winds may occur with the strongest cores.

$$

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ACUS01 KWNS 080037
SWODY1
SPC AC 080035

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0735 PM CDT Wed May 07 2025

Valid 080100Z - 081200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
An appreciable severe threat is not expected across the continental
United States through daybreak on Thursday.

...DISCUSSION...
Latest water vapor imagery shows a mid-level low over eastern
Kansas, with a long fetch of west-southwesterly flow from the
southern Plains to the East Coast. Isolated to scattered
thunderstorms will be possible this evening from the vicinity of the
low southeastward into part of the mid Mississippi Valley, Tennessee
Valley and Southeast. Additional storms will be possible this
evening in parts of the Desert Southwest and from the central
Rockies into the central High Plains. Organized severe convection is
not expected through daybreak Thursday morning.

..Broyles.. 05/08/2025

$$

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ACUS01 KWNS 080555
SWODY1
SPC AC 080554

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Thu May 08 2025

Valid 081200Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS THE
SOUTHERN APPALACHIANS...TENNESSEE VALLEY...SOUTHEAST AND RIO GRANDE
VALLEY...

...SUMMARY...
Isolated to scattered thunderstorms with severe gusts and large hail
are expected today over parts of the southern Appalachians,
Tennessee Valley and Southeast. Hailstones greater than 2 inches in
diameter will be possible. Severe gusts and large hail will also be
possible in parts of the Rio Grande Valley.

...Southern Appalachians/Tennessee Valley/Southeast...
A positively-tilted mid-level trough, and an associated cold front,
will move through the Ohio and mid Mississippi Valleys today.
Surface dewpoints to the south of the front will range from the mid
50s to the mid 60s F. As surface temperatures warm during the day,
moderate instability is expected to develop across much of the moist
airmass. A cluster of organized thunderstorms is forecast to develop
in the afternoon from western and central Kentucky into middle
Tennessee, and eastward into the southern Appalachians. This large
cluster will move southeastward into northern Alabama, northern
Georgia and the western Carolinas by late afternoon. RAP forecast
soundings along the zone of maximum instability have 0-6 km shear in
the 35 to 45 knot range, with 850 to 500 mb lapse rates near 7 C/km.
This environment will support the development of supercells with
large hail, in areas where the storms can remain semi-discrete.
Hailstones greater than 2 inches in diameter will be possible with
the more intense supercells. In addition, forecast soundings show
very steep low-level lapse exceeding 8 C/km, which will be
supportive of damaging wind gusts.

Further to the south from parts of the Southeast into northern
Florida, moderate instability is expected to develop during the
afternoon in an airmass with surface dewpoints in the mid to upper
60s F. In spite of weaker large-scale ascent, isolated to scattered thunderstorms are expected to develop in areas that heat up the
most. 0-6 km shear in the 25 to 35 knot range and steep low-level
lapse rates could support a marginal threat for severe gusts and
hail during the mid to late afternoon.

...Rio Grande Valley...
A mid-level trough will move through northern Mexico today, as flow
remains from the west across the southern Plains. Ahead of the
trough, an axis of moderate instability will be in place across the
Rio Grande Valley. As surface temperatures warm today, scattered
thunderstorms are expected to develop in the higher terrain of
northern Mexico, with convection spreading eastward into the Rio
Grande Valley. Along much of the instability axis, forecast
soundings by afternoon have 0-6 km shear in the 40 to 50 knot range,
with 0-3 km lapse rates near or above 8 C/km. In addition, lapse
rates are steep in the mid-levels. This environment should enable
supercells to develop with a potential for large hail and damaging
wind gusts. The severe threat is expected to first develop in parts
of west and southwest Texas in the early afternoon, gradually
spreading southeastward into south-central and south Texas by late
afternoon.

..Broyles/Moore.. 05/08/2025

$$

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ACUS01 KWNS 081300
SWODY1
SPC AC 081259

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 AM CDT Thu May 08 2025

Valid 081300Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
TENNESSEE VALLEY...SOUTHERN APPALACHIANS...SOUTHEAST AND THE RIO
GRANDE VALLEY OF TEXAS...

...SUMMARY...
Scattered thunderstorms with severe wind gusts and large hail are
expected today over parts of the Tennessee Valley, and southern
Appalachians, with hailstones greater than 2 inches in diameter
possible. Severe wind gusts and large hail will also be possible in
other parts of the Southeast, as well as West/South Texas including
the Rio Grande Valley.

...Tennessee Valley/Southern Appalachians to Southeast...
A positively-tilted mid-level trough, with an upper low centered
over the Ozarks this morning, will move through the Ohio and mid
Mississippi Valleys today, and toward the Appalachians tonight.
Surface dewpoints to the south of an advancing cold front will range
from the mid 50s to the mid 60s F. As surface temperatures warm
during the day, moderate instability is expected to develop with
minimal convective inhibition beneath relatively cool mid-level
temperatures via the proximity of the upper cold pocket.

Storms will steadily increase into the afternoon with some
supercells and organizing clusters from western and central Kentucky
into middle Tennessee, eastward into the southern Appalachians.
These storms will develop south-southeastward into northern Alabama,
northern Georgia and the western Carolinas by late afternoon. Large
hail can be expected, with hail greater than 2 inches in diameter
possible especially with the more discrete and intense supercells.
Damaging wind gusts can also be expected regionally.

Another relatively favorable area for severe storms may focus across
southeast Georgia and nearby far southern South Carolina and/or far
north Florida this afternoon through early evening. This will be
coincident with somewhat stronger mid-level flow as compared to
areas farther south across the northern/central Florida Peninsula,
where isolated severe storms are still expected. Regarding northern
Florida this morning, see Mesoscale Discussion 738.

...West/South Texas including Rio Grande Valley...
A low-latitude shortwave trough will progress east-southeastward
across far northern Mexico and along the Rio Grande Valley today and
tonight. A corridor of moderate to strong instability will be in
place across the Rio Grande Valley. As surface temperatures warm
today, scattered thunderstorms are expected to develop in the higher
terrain of northern Mexico, with convection spreading eastward into
and across the Rio Grande Valley, potentially with multiple
rounds/corridors of severe weather possible across South Texas.
Regarding short-term severe potential across South Texas, see
Mesoscale Discussion 739. Strong deep-layer shear will contribute to
supercells capable of large to very large hail and damaging wind
gusts, especially if storms cluster/organize across the Rio Grande
Valley later this afternoon into evening.

..Guyer/Dean.. 05/08/2025

$$

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ACUS01 KWNS 081630
SWODY1
SPC AC 081628

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Thu May 08 2025

Valid 081630Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF THE
MID-SOUTH INTO THE TENNESSEE VALLEY AND SOUTHEAST...AND PARTS OF THE
RIO GRANDE VALLEY IN TEXAS...

...SUMMARY...
Scattered thunderstorms with severe wind gusts and large hail are
expected today over parts of the Tennessee Valley and southern Appalachians/Southeast, with isolated very large hail possible.
Severe wind gusts and large to very large hail will also be possible
across portions of west/south Texas including the Rio Grande Valley.

...Tennessee Valley/Southeast Appalachians into the Southeast...
A positively tilted upper trough will extend from Ontario and the
Northeast southwestward across the Great Lakes, OH/TN Valley, and
into the Mid-South and southern Plains today. A weak surface low
analyzed this morning over the mid MS Valley is forecast to
gradually fill/lose definition through the afternoon/evening, as a
weak cold front moves slowly south-southeastward through the period.
Areas of at least scattered to broken clouds remain evident on
recent visible satellite imagery from northern MS/western TN to the
southern Appalachians. This will tend to hinder diurnal
destabilization to some extent, but cool temperatures aloft (around
-13 to -16C at 500 mb from area 12Z soundings) and modestly
steepened mid-level lapse rates should compensate to some extent.

Within the broader upper troughing, a weak embedded upper low/trough
will continue to advance slowly eastward from the mid MS Valley to
the TN Valley and southern Appalachians through this evening. Modest large-scale ascent associated with this feature, along with weak
low-level convergence along the cold front, should be sufficient to
aid in at least scattered convective development across these
regions this afternoon. A combination of moderate instability and
around 30-40 kt of effective bulk shear appear adequate to support
some thunderstorm organization. Multiple supercells and short line segments/clusters should develop and spread east-southeast this afternoon/evening across parts of the Mid-South into the TN Valley
and southern Appalachians. Large hail will be possible with
sustained supercells, and isolated very large hail (potentially up
to 2-2.5 inches in diameter) could also occur. Otherwise,
severe/damaging winds will also be a concern with any clusters.
Based on latest observational and guidance trends showing a
favorable environment this afternoon and evening across a broader
portion of the TN Valley/Southeast, the Slight Risk has been
expanded westward some across the Mid-South/lower OH Valley where
convection is initiating, and eastward to include more of
north/central GA, and the western/central Carolinas into
south-central VA.

A somewhat separate area of strong to severe thunderstorms may focus
along/near the Atlantic Coast sea breeze this afternoon from parts
of coastal/southeast GA to the east-central FL Peninsula. Seasonably
cool temperatures aloft combined with moderate to strong instability
and a generally long/straight hodograph at mid/upper-levels should
support some threat for both large hail and damaging winds with any cells/clusters that can form.

...Rio Grande Valley...
Thunderstorms are ongoing late this morning across parts of west TX,
in association with a weak shortwave trough over northern Mexico and
related modest low-level warm/moist advection. Current expectations
are for this activity to gradually increase in coverage and
intensity across the Big Bend region and vicinity through the
afternoon as daytime heating acts to further destabilize an already
moist low-level airmass. While mid-level winds are not forecast to
be overly strong with the low-amplitude shortwave trough, veering
winds with height will support deep-layer shear around 35-45 kt.
Supercells should be the primary convective mode initially, with a
threat for scattered large to very large hail (generally 1.5-2.5
inches in diameter) and isolated severe winds.

Additional intense convection should develop over the higher terrain
of north-central to northeast Mexico, with some potential for this
activity to spread east-southeastward across the Rio Grande Valley
this afternoon and evening in a moderately to strongly unstable
airmass. Large hail will continue to be a threat with any sustained
supercells, and the threat for severe/damaging winds may also
increase if a small cluster/MCS can develop and spread southeastward
this evening and tonight. Finally, a separate area of strong to
severe thunderstorms may develop through the afternoon along/near
the coast and a stalled front in deep south TX. This activity would
also pose some threat for severe hail/wind given a very
moist/unstable airmass and sufficient deep-layer shear for organized
updrafts.

..Gleason/Thornton.. 05/08/2025

$$

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ACUS01 KWNS 081959
SWODY1
SPC AC 081957

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Thu May 08 2025

Valid 082000Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF THE
MID-SOUTH INTO THE TENNESSEE VALLEY AND SOUTHEAST...AND PARTS OF THE
RIO GRANDE VALLEY IN TEXAS...

...SUMMARY...
Scattered thunderstorms with severe wind gusts and large hail are
expected today over parts of the Tennessee Valley and southern Appalachians/Southeast, with isolated very large hail possible.
Severe wind gusts and large to very large hail will also be possible
across portions of west/south Texas including the Rio Grande Valley.

...20Z Update...
The forecast remains on track, and only minor adjustments were made
with this update. In particular, the Slight Risk along the Rio
Grande Valley in Texas was expanded northward, where scattered
thunderstorms are gradually intensifying in a moist/unstable air
mass with 40-50 kt of effective shear. Reference MCD 745 for more
details. Farther east, widely scattered thunderstorms -- including
several discrete supercell structures -- are spreading eastward
across Severe Thunderstorm Watches 238, 239, and 240. The only
change to the outlook here was a minor expansion of the
significant-hail probabilities ahead of evolving supercells. For
details, reference MCDs 743 and 744.

..Weinman.. 05/08/2025

.PREV DISCUSSION... /ISSUED 1128 AM CDT Thu May 08 2025/

...Tennessee Valley/Southeast Appalachians into the Southeast...
A positively tilted upper trough will extend from Ontario and the
Northeast southwestward across the Great Lakes, OH/TN Valley, and
into the Mid-South and southern Plains today. A weak surface low
analyzed this morning over the mid MS Valley is forecast to
gradually fill/lose definition through the afternoon/evening, as a
weak cold front moves slowly south-southeastward through the period.
Areas of at least scattered to broken clouds remain evident on
recent visible satellite imagery from northern MS/western TN to the
southern Appalachians. This will tend to hinder diurnal
destabilization to some extent, but cool temperatures aloft (around
-13 to -16C at 500 mb from area 12Z soundings) and modestly
steepened mid-level lapse rates should compensate to some extent.

Within the broader upper troughing, a weak embedded upper low/trough
will continue to advance slowly eastward from the mid MS Valley to
the TN Valley and southern Appalachians through this evening. Modest large-scale ascent associated with this feature, along with weak
low-level convergence along the cold front, should be sufficient to
aid in at least scattered convective development across these
regions this afternoon. A combination of moderate instability and
around 30-40 kt of effective bulk shear appear adequate to support
some thunderstorm organization. Multiple supercells and short line segments/clusters should develop and spread east-southeast this afternoon/evening across parts of the Mid-South into the TN Valley
and southern Appalachians. Large hail will be possible with
sustained supercells, and isolated very large hail (potentially up
to 2-2.5 inches in diameter) could also occur. Otherwise,
severe/damaging winds will also be a concern with any clusters.
Based on latest observational and guidance trends showing a
favorable environment this afternoon and evening across a broader
portion of the TN Valley/Southeast, the Slight Risk has been
expanded westward some across the Mid-South/lower OH Valley where
convection is initiating, and eastward to include more of
north/central GA, and the western/central Carolinas into
south-central VA.

A somewhat separate area of strong to severe thunderstorms may focus
along/near the Atlantic Coast sea breeze this afternoon from parts
of coastal/southeast GA to the east-central FL Peninsula. Seasonably
cool temperatures aloft combined with moderate to strong instability
and a generally long/straight hodograph at mid/upper-levels should
support some threat for both large hail and damaging winds with any cells/clusters that can form.

...Rio Grande Valley...
Thunderstorms are ongoing late this morning across parts of west TX,
in association with a weak shortwave trough over northern Mexico and
related modest low-level warm/moist advection. Current expectations
are for this activity to gradually increase in coverage and
intensity across the Big Bend region and vicinity through the
afternoon as daytime heating acts to further destabilize an already
moist low-level airmass. While mid-level winds are not forecast to
be overly strong with the low-amplitude shortwave trough, veering
winds with height will support deep-layer shear around 35-45 kt.
Supercells should be the primary convective mode initially, with a
threat for scattered large to very large hail (generally 1.5-2.5
inches in diameter) and isolated severe winds.

Additional intense convection should develop over the higher terrain
of north-central to northeast Mexico, with some potential for this
activity to spread east-southeastward across the Rio Grande Valley
this afternoon and evening in a moderately to strongly unstable
airmass. Large hail will continue to be a threat with any sustained
supercells, and the threat for severe/damaging winds may also
increase if a small cluster/MCS can develop and spread southeastward
this evening and tonight. Finally, a separate area of strong to
severe thunderstorms may develop through the afternoon along/near
the coast and a stalled front in deep south TX. This activity would
also pose some threat for severe hail/wind given a very
moist/unstable airmass and sufficient deep-layer shear for organized
updrafts.

$$

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ACUS01 KWNS 090103
SWODY1
SPC AC 090101

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0801 PM CDT Thu May 08 2025

Valid 090100Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTH TEXAS...THE TENNESSEE VALLEY...SOUTHERN APPALACHIANS AND
SOUTHEAST...

...SUMMARY...
Scattered thunderstorms with severe wind gusts and large hail will
continue this evening over parts of the Tennessee Valley, southern
Appalachians and Southeast. Severe wind gusts and large hail are
also expected across parts of south Texas, where hailstones of
greater than 2 inches in diameter will be possible.

...Tennessee Valley/Southern Appalachians/Southeast...
Latest water vapor imagery shows a positively-tilted mid-level
trough over the Ohio Valley, with an east-to-west oriented plume of
mid-level moisture from the mid Mississippi Valley into the south
and central Appalachians. At the surface, a quasi-stationary front
is analyzed in the Ohio Valley. To the south of the front over the
Ohio and Tennessee Valleys, surface dewpoints are in the mid 50s to
the mid 60s F. The RAP has moderate instability in place from the
Tennessee Valley eastward into the southern Appalachians and
southward into the Gulf Coast states. Scattered thunderstorms are
ongoing, concentrated along the northern edge of moderate
instability from Kentucky and Tennessee eastward into western North
Carolina. RAP forecast soundings in this vicinity early this evening
have 0-6 km shear ranging from 35 to 45 knots, mostly due to speed
shear in the mid-levels. This, combined with 0-3 km lapse rates in
the 7.5 to 8 C/km range, should be favorable for severe gusts with
the stronger cells. The shear will also support supercell
development with large hail possible. The severe threat should
become more isolated later this evening as instability decreases
across the region.

...South Texas...
A shortwave trough, with multiple vorticity maximums, appears to be
located in the lower Rio Grande Valley, according to water vapor
imagery. Scattered strong to severe thunderstorms are ongoing ahead
of the trough from near Laredo extending eastward onto the Texas
Coastal Plain. From the storms southward, moderate instability is
analyzed by the RAP, with MLCAPE estimated to be in the 1000 to 2000
J/kg range. The airmass is very moist with surface dewpoints in the
lower to mid 70s F. Within this moist airmass, RAP forecast
soundings early this evening have 0-6 km shear near 50 knots, with
700-500 mb lapse rates near 7.5 C/km. This environment will support
supercells with large hail, and hailstones greater than 2 inches in
diameter will be possible within the more intense cores. Isolated
severe gusts may also occur within the stronger downdrafts. The
ongoing severe storms will track southeastward across the remainder
of south Texas this evening...see MCD 749.

..Broyles.. 05/09/2025

$$

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ACUS01 KWNS 090543
SWODY1
SPC AC 090541

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1241 AM CDT Fri May 09 2025

Valid 091200Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PART OF
EASTERN NORTH CAROLINA AND EASTERN FLORIDA...

...SUMMARY...
Thunderstorms capable of producing large hail and severe gusts will
be possible today across parts of eastern North Carolina.
Thunderstorms with potential for severe gusts and hail may also form
over eastern Florida. A marginal severe threat is also expected to
develop outside of the Slight Risk areas from parts of the Southeast northeastward to southern Maryland.

...Southeast...
At mid-levels today, flow will remain west-southwesterly across the southeastern U.S. At the surface, a very moist airmass will remain
from Florida to the central Gulf Coast, where surface dewpoints will
be from the mid 60s to lower 70s F. The greatest instability is
forecast across the eastern Florida Peninsula, where the models are
in generally good agreement that MLCAPE will peak in the 2000 to
3000 J/kg range. As instability increases during the day,
thunderstorms are expected to develop along a sea breeze boundary in
eastern Florida. RAP forecast soundings near the boundary have 0-6
km shear in the 35 to 40 knot range with some directional shear at
low-levels. In addition, 0-3 km lapse rates are forecast to peak in
the 7.5 to 8 C/km range. This should be enough for a wind-damage
threat with the stronger cells that form near the boundary. The
potential for severe gusts is expected to be concentrated in the mid
to late afternoon near max heating. A marginal and isolated severe
threat will also be possible westward across parts of the central
Gulf Coast states during the afternoon.

...Carolinas/Southeast Virginia/Southern Maryland...
A positively-tilted mid-level trough will move through the Ohio
Valley today, as west-southwesterly flow remains in place across the
Atlantic Seaboard. A surface low will move northeastward into the
Mid-Atlantic, as a cold front moves across the Atlantic Coastal
Plains. Ahead of the front, surface dewpoints will be in the 60s F.
As surface heating takes place during the day, destabilization is
expected near the Atlantic coast in the eastern Carolinas. MLCAPE is
expected to peak in the 1000 to 1200 J/kg range during the early
afternoon. RAP forecast soundings at 20Z in eastern North Carolina
have 0-6 km shear around 40 knots, with 0-3 km lapse rates in the 8
to 8.5 C/km range. In addition, mid-level lapse rates are forecast
to be steep around 700 mb. This environment could support supercells
with potential for large hail and severe wind gusts. The threat
should end by early evening, as the more favorable environment moves
offshore.

..Broyles/Lyons.. 05/09/2025

$$

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ACUS01 KWNS 091242
SWODY1
SPC AC 091241

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0741 AM CDT Fri May 09 2025

Valid 091300Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE FL PENINSULA AND FAR SOUTHEAST VA/NORTHEAST NC...

...SUMMARY...
Thunderstorms capable of producing large hail and severe wind gusts
are possible across parts of the Southeast, but especially areas
such as the northern Florida Peninsula and eastern North
Carolina/far southeast Virginia.

...Florida/coastal Southeast...
Weak height falls and strengthening southwesterly winds aloft will
occur later today into tonight preceding the upper trough along the
middle Gulf Coast and lower Mississippi River Valley, with an MCS
over the west-central/north-central Gulf also a factor. The
relatively greatest destabilization is expected today across the northern/central Florida Peninsula and nearby Georgia, where
guidance is in generally good agreement that MLCAPE will peak in the
2000-3000 J/kg range this afternoon. As instability increases during
the day, thunderstorms are expected to develop with sea breeze
influences, with isolated large hail and damaging winds possible.
Elsewhere, influences from the aforementioned MCS over the Gulf
should limited severe potential farther west along the middle Gulf
Coast, although some measure of recovery and weak cyclogenesis could
occur later tonight toward far southeast Louisiana to Florida
Panhandle vicinity.

...Carolinas/southeast Virginia/southern Maryland...
The closed upper low will shift generally eastward over the
central/northern Appalachians and northern Mid-Atlantic region
today, with a cyclonically curved belt of strong westerlies in its
base and attendant mid-level cold pocket (-18C to -24C at 500 mb).
Some showers/possibly a thunderstorm will exit the region and move
into the Atlantic today, with modest air mass
recovery/destabilization in its wake preceding a surface
low/reinforcing front. While the magnitude of the severe risk is not
entirely clear, the main opportunity for later-day strong/locally
severe storm development would appear to be across far southeast
Virginia and far northeast North Carolina. Strong wind profiles
would support organized storms pending sufficient destabilization,
with potential for severe hail and damaging winds, at least on an
isolated basis, primarily from mid-afternoon through sunset or early
evening.

..Guyer/Dean.. 05/09/2025

$$

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ACUS01 KWNS 091631
SWODY1
SPC AC 091630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Fri May 09 2025

Valid 091630Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN
FLORIDA PENINSULA INTO SOUTHEAST GEORGIA AND FAR SOUTHERN SOUTH
CAROLINA...AND ACROSS EASTERN NORTH CAROLINA/FAR SOUTHEAST
VIRGINIA...

...SUMMARY...
Thunderstorms capable of producing large hail and severe wind gusts
are possible across parts of the Mid-Atlantic and Southeast,
especially from the eastern Florida Peninsula through southeast
Georgia, and across northeastern North Carolina/far southeast
Virginia.

...Synopsis...
Recent satellite imagery shows a pair of cyclones embedded within a
large positively titled upper trough extending from the southern
Plains through the Northeast. The northernmost/easternmost cyclone
is centered over the Lower Great Lakes vicinity, and is forecast to
move gradually eastward throughout the day, ending the period over
southern New England. An associated surface low, which is currently
centered over eastern NJ, is forecast to progress northeastward
while becoming increasingly aligned with the mid-level cyclone. A
cold front extends southwestward from this low across VA and then
back westward across KY, southern IL, and central MO. As the low
moves northeastward, this front is expected to gradually push southward/southeastward, moving through much of the Mid-Atlantic by
this evening.

The southernmost/westernmost embedded cyclone is currently centered
over southern AR, and the expectation is for the cyclone to shift
southeastward throughout the day, ending the period over the Lower
MS Valley. Primary surface low associated with this system is
currently over the northwest Gulf. This low is forecast to progress
slowly eastward along the central Gulf coast, remaining just off
shore and likely reaching just off AL/MS border intersection by
early tomorrow morning.

...Central Gulf Coast into FL...
A modest, convectively enhanced vorticity maximum is forecast to
move from the central FL Panhandle into southeast GA/northern FL
today, well ahead of the mid-level cyclone and associated surface
low described in the synopsis. Localized ascent attendant to this
features coupled with modest large-scale forcing for ascent and
airmass destabilization will result in early-afternoon thunderstorm development, particularly along any sea breeze boundary that
develops. Vertical shear will be modest, resulting in a mostly
multicellular mode. Even so, updrafts are still expected to be
strong enough to produce damaging downbursts and isolated large
hail.

Later tonight, some additional organization/strengthening of a
convective line near the surface low is possible. Some strengthening
of the low-level flow could occur at the same time, resulting in a low-probability tornado risk along the coast from AL into the
western and central FL Peninsula.

...Mid-Atlantic into the Carolinas...
Afternoon thunderstorm development is anticipated across the region,
with the highest coverage from the VA Tidewater into east-central
NC, where forcing along the cold front will be strongest. The
strongest shear is anticipated across this region as well, but the
overall magnitude should still be modest, with most guidance
suggesting deep-layer shear around 35 kt. Buoyancy will be modest as
well, with MLCAPE likely maximizing around 800 to 1000 J/kg. These environmental conditions support the potential for a few stronger,
more organized updrafts capable of damaging wind gusts and isolated
large hail.

..Mosier/Squitieri.. 05/09/2025

$$

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ACUS01 KWNS 091959
SWODY1
SPC AC 091958

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Fri May 09 2025

Valid 092000Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN
FLORIDA PENINSULA INTO SOUTHEAST GEORGIA AND FAR SOUTHERN SOUTH
CAROLINA...AND ACROSS EASTERN NORTH CAROLINA/FAR SOUTHEAST
VIRGINIA...

...SUMMARY...
Thunderstorms capable of producing large hail and severe wind gusts
are possible across parts of the Mid-Atlantic and Southeast,
especially from the eastern Florida Peninsula through southeast
Georgia, and across northeastern North Carolina/far southeast
Virginia.

...20Z Update...
No changes were made to the forecast with this update. For details
on the near-term severe risks in the Mid-Atlantic and
northern/central FL, reference MCDs #753 and #754. For the overnight
and early morning time frame, a locally favorable corridor for tornadoes/waterspouts may develop in the vicinity of the western FL
Panhandle -- focused ahead of a well-defined MCV tracking eastward
across the north-central Gulf. However, confidence in adding higher
tornado probabilities is too low at this time, given
ongoing/additional convection and related boundary-layer
overturning.

..Weinman.. 05/09/2025

.PREV DISCUSSION... /ISSUED 1130 AM CDT Fri May 09 2025/

...Synopsis...
Recent satellite imagery shows a pair of cyclones embedded within a
large positively titled upper trough extending from the southern
Plains through the Northeast. The northernmost/easternmost cyclone
is centered over the Lower Great Lakes vicinity, and is forecast to
move gradually eastward throughout the day, ending the period over
southern New England. An associated surface low, which is currently
centered over eastern NJ, is forecast to progress northeastward
while becoming increasingly aligned with the mid-level cyclone. A
cold front extends southwestward from this low across VA and then
back westward across KY, southern IL, and central MO. As the low
moves northeastward, this front is expected to gradually push southward/southeastward, moving through much of the Mid-Atlantic by
this evening.

The southernmost/westernmost embedded cyclone is currently centered
over southern AR, and the expectation is for the cyclone to shift
southeastward throughout the day, ending the period over the Lower
MS Valley. Primary surface low associated with this system is
currently over the northwest Gulf. This low is forecast to progress
slowly eastward along the central Gulf coast, remaining just off
shore and likely reaching just off AL/MS border intersection by
early tomorrow morning.

...Central Gulf Coast into FL...
A modest, convectively enhanced vorticity maximum is forecast to
move from the central FL Panhandle into southeast GA/northern FL
today, well ahead of the mid-level cyclone and associated surface
low described in the synopsis. Localized ascent attendant to this
features coupled with modest large-scale forcing for ascent and
airmass destabilization will result in early-afternoon thunderstorm development, particularly along any sea breeze boundary that
develops. Vertical shear will be modest, resulting in a mostly
multicellular mode. Even so, updrafts are still expected to be
strong enough to produce damaging downbursts and isolated large
hail.

Later tonight, some additional organization/strengthening of a
convective line near the surface low is possible. Some strengthening
of the low-level flow could occur at the same time, resulting in a low-probability tornado risk along the coast from AL into the
western and central FL Peninsula.

...Mid-Atlantic into the Carolinas...
Afternoon thunderstorm development is anticipated across the region,
with the highest coverage from the VA Tidewater into east-central
NC, where forcing along the cold front will be strongest. The
strongest shear is anticipated across this region as well, but the
overall magnitude should still be modest, with most guidance
suggesting deep-layer shear around 35 kt. Buoyancy will be modest as
well, with MLCAPE likely maximizing around 800 to 1000 J/kg. These environmental conditions support the potential for a few stronger,
more organized updrafts capable of damaging wind gusts and isolated
large hail.

$$

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ACUS01 KWNS 100053
SWODY1
SPC AC 100051

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 PM CDT Fri May 09 2025

Valid 100100Z - 101200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE FLORIDA
PANHANDLE AND THE MOBILE BAY VICINITY...

...SUMMARY...
An isolated severe risk may develop tonight over portions of the
northern Gulf Coast.

...Discussion...
Water-vapor imagery this evening shows a split-flow regime over
North America. A mid-level trough over the Mid-Atlantic states will
move northeast to southern New England, while a slow-moving
mid-level low meanders over the north Gulf Coast through early
Saturday morning. Model guidance indicates weak cyclogenesis over
the northern Gulf of America tonight with this low moving to near
Mobile Bay by daybreak Saturday. A strengthening of low-level
warm-air advection and associated flow may aid supporting an
environment where a few stronger storms develop tonight from the
shelf waters inland into the region centered on the FL Panhandle.
Forecast soundings show weakly buoyant profiles with some
enlargement to the hodograph. A transient supercell capable of a
brief tornado/wind damage near the coast would be the primary
threat.

Elsewhere, convective overturning across parts of the Southeast and
the onset of nocturnal cooling will continue to lead to weakening
thunderstorm activity this evening.

..Smith.. 05/10/2025

$$

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ACUS01 KWNS 100551
SWODY1
SPC AC 100549

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1249 AM CDT Sat May 10 2025

Valid 101200Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
SOUTHEAST AND THE NORTHERN ROCKIES AND ADJACENT HIGH PLAINS...

...SUMMARY...
Isolated severe thunderstorms are possible over parts of the
Southeast today, and the northern Rockies and adjacent High Plains
this afternoon through the evening.

...Synopsis...
A mid to upper-level low will meander over Louisiana today with
troughing encompassing the western Gulf basin. In the low levels, a
weak surface low is forecast to move northward and inland from the
MS/AL coast, with a stationary front over southern AL and GA.

Farther west, a belt of strong southwesterly mid-level flow will
extend from the Pacific Northwest into the southern Prairie
Provinces, downstream of an eastward migrating trough forecast to
approach the Pacific Northwest coast early Sunday morning. The
higher-momentum flow is expected to glance the northern High Plains.

...FL into far southern GA/AL...
A moist and moderately unstable air mass will exist south of the
frontal zone. Scattered to numerous storms are forecast over parts
of the Gulf extending from southern AL into the FL Panhandle during
the day. A few of the stronger storms may organize given the
veering wind profiles and sufficient effective shear. An isolated
risk for all hazards may develop over the FL Panhandle during the
day, while smaller hodographs farther south into the Peninsula will
tend to favor mostly an isolated hail/wind farther south.

...MT/ID...
Strong heating and orographic lift over southwest MT will favor
widely scattered thunderstorms developing by mid-late afternoon.
Very steep low-level lapse rates and a relatively dry sub-cloud
layer will promote efficient evaporative cooling with the stronger
cores as storms mature as they move northeast. A couple of clusters
are possible with severe outflow. This activity will likely spread
into northern/northeast MT during the evening. Farther south,
isolated to widely scattered thunderstorms are forecast during the
afternoon. Similar to farther north, steep lapse rates will favor
isolated severe gusts with the stronger cores.

..Smith/Lyons.. 05/10/2025

$$

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ACUS01 KWNS 101259
SWODY1
SPC AC 101257

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 AM CDT Sat May 10 2025

Valid 101300Z - 111200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PANHANDLE...SOUTHEAST ALABAMA...AND SOUTHWEST GEORGIA...

...SUMMARY...
Severe thunderstorms including a damaging wind and tornado risk may
occur across parts of the Southeast, including northern Florida,
southern Alabama and southern Georgia. Other thunderstorms with
strong winds will be possible across the northern Rockies this
afternoon and evening.

...Southeast including FL and far southeast AL/southern GA...
Multiple areas of strong storms are ongoing early this morning over
the northeast Gulf of America, originating within a moist/unstable
warm sector that continues to nudge closer to the coastal Florida
Panhandle and Big Bend. As a moist low-level level influx continues,
a severe threat will exist today particularly for coastal areas,
with the northern extent of the severe risk not entirely clear.
However, some severe risk should exist as far north as the weak
surface low and warm front effectively makes a northward
progression. Where sufficient destabilization does occur, moderately strong/veering wind profiles will support storms capable of damaging
winds and some tornado potential. This appears to mainly be across
the Florida Panhandle, southeast Alabama, and southwest Georgia.
Non-supercell processes might even be a factor for funnel/brief
tornado potential farther west-northwest across Alabama toward the
frontal wave/surface triple point, in closer proximity to the upper
low. Otherwise, more of a damaging wind/some hail risk will exist
southward across parts of the Florida Peninsula. For short-term info
for northeast Florida/southeast Georgia, see Mesoscale Discussion
757.

...Montana/Idaho...
Strong heating and orographic lift over western Montana will favor
widely scattered thunderstorms developing by mid-late afternoon.
Very steep low-level lapse rates and a relatively dry sub-cloud
layers will promote efficient evaporative cooling with the stronger
cores as storms mature as they move northeast. A couple of clusters
are possible with severe outflow. This activity will likely spread
into northern/northeast Montana during the evening.

..Guyer/Dean.. 05/10/2025

$$

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ACUS01 KWNS 101625
SWODY1
SPC AC 101623

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1123 AM CDT Sat May 10 2025

Valid 101630Z - 111200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PANHANDLE...SOUTHEAST ALABAMA...AND SOUTHWEST GEORGIA...

...SUMMARY...
Severe thunderstorms including a damaging wind and tornado risk may
occur across parts of the Southeast, including northern Florida,
southern Alabama and southern Georgia. Other thunderstorms with
strong winds will be possible across the northern Rockies this
afternoon and evening.

...Southeast including FL and far southeast AL/southern GA...
Recent surface analysis places a low over the MOB vicinity, with a
warm front extending eastward along the FL/AL border into far
southwest GA and a cold front extending southward into the central
Gulf. Thunderstorms have developed along and just ahead of this
front, amid modest low-level convergence. A belt of enhanced
southerly low-level flow exists across this warm sector, which has
contributed to transient low-level mesocyclone intensification. This
belt of enhanced low-level flow is expected to persist throughout
the afternoon, resulting in a relatively narrow corridor of greater
severe storm potential from the central FL Peninsula into far
southeast AL and far southwest GA. This area was discussed in
recently issued MCD #0758, which mentioned the storms are forecast
to gradually increase in coverage and intensity during the day, and
that a few of these storms may produce severe weather including
brief tornadoes. Tornado Watch #244 was also recently issued to
cover this severe-weather potential.

Thunderstorm coverage is also expected to increase along and north
of the warm front from central AL into central GA during the
afternoon and evening. Moderate vertical shear will be in place, but
buoyancy will be weak and the general expectation is for storms to
remain sub-severe. Increasing thunderstorm coverage is also expected
across the FL Peninsula this afternoon amid modest low-level
confluence and strong heating. Vertical shear will be weak, limiting
storm organization, but a few strong downbursts and isolated
instances of hail are still possible.

...Montana/Idaho...
Strong heating is anticipated across the northern Rockies/northern
High Plains, resulting in a deeply mixed boundary layer by the mid
to late afternoon. Persistent southwesterly flow and resulting
orographic ascent is expected to result in thunderstorm development
across the higher terrain. Very steep low-level lapse rates and
relatively dry sub-cloud layers will promote efficient evaporative
cooling with the stronger cores as storms mature as they move
northeast. A couple of clusters are possible with severe outflow.
This activity will likely spread into northern/northeast Montana
during the evening.

..Mosier/Barnes.. 05/10/2025

$$

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ACUS01 KWNS 102000
SWODY1
SPC AC 101958

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Sat May 10 2025

Valid 102000Z - 111200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PANHANDLE...SOUTHEAST ALABAMA...AND SOUTHWEST GEORGIA...

...SUMMARY...
Severe thunderstorms including a damaging wind and tornado risk may
occur across parts of the Southeast, including northern Florida,
southern Alabama and southern Georgia. Other thunderstorms with
strong winds will be possible across the northern Rockies this
afternoon and evening.

...20Z Update...
The forecast remains on track, and very minimal changes were made
with this update. The greatest tornado risk has generally shifted
northward into southeast AL and southwest GA -- where low-level SRH
is maximized along the warm front. Reference Tornado Watch #244 and
MCD #760 for more details. An additional uptick in tornado potential
is possible farther south into the FL Panhandle late in the forecast
period, as the low-level jet re-strengthens over the eastern Gulf.
The 5-percent tornado probabilities have been maintained here for
this scenario.

..Weinman.. 05/10/2025

.PREV DISCUSSION... /ISSUED 1123 AM CDT Sat May 10 2025/

...Southeast including FL and far southeast AL/southern GA...
Recent surface analysis places a low over the MOB vicinity, with a
warm front extending eastward along the FL/AL border into far
southwest GA and a cold front extending southward into the central
Gulf. Thunderstorms have developed along and just ahead of this
front, amid modest low-level convergence. A belt of enhanced
southerly low-level flow exists across this warm sector, which has
contributed to transient low-level mesocyclone intensification. This
belt of enhanced low-level flow is expected to persist throughout
the afternoon, resulting in a relatively narrow corridor of greater
severe storm potential from the central FL Peninsula into far
southeast AL and far southwest GA. This area was discussed in
recently issued MCD #0758, which mentioned the storms are forecast
to gradually increase in coverage and intensity during the day, and
that a few of these storms may produce severe weather including
brief tornadoes. Tornado Watch #244 was also recently issued to
cover this severe-weather potential.

Thunderstorm coverage is also expected to increase along and north
of the warm front from central AL into central GA during the
afternoon and evening. Moderate vertical shear will be in place, but
buoyancy will be weak and the general expectation is for storms to
remain sub-severe. Increasing thunderstorm coverage is also expected
across the FL Peninsula this afternoon amid modest low-level
confluence and strong heating. Vertical shear will be weak, limiting
storm organization, but a few strong downbursts and isolated
instances of hail are still possible.

...Montana/Idaho...
Strong heating is anticipated across the northern Rockies/northern
High Plains, resulting in a deeply mixed boundary layer by the mid
to late afternoon. Persistent southwesterly flow and resulting
orographic ascent is expected to result in thunderstorm development
across the higher terrain. Very steep low-level lapse rates and
relatively dry sub-cloud layers will promote efficient evaporative
cooling with the stronger cores as storms mature as they move
northeast. A couple of clusters are possible with severe outflow.
This activity will likely spread into northern/northeast Montana
during the evening.

$$

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ACUS01 KWNS 110050
SWODY1
SPC AC 110048

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0748 PM CDT Sat May 10 2025

Valid 110100Z - 111200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE
SOUTHEAST AND NORTHERN ROCKIES...

...SUMMARY...
Isolated severe gusts may persist this evening over parts of the
northern Rockies. A brief tornado or two, along with locally
damaging winds are possible across parts of the Southeast into
Sunday morning.

...Southeast...
Primary severe potential early tonight should be confined to near
the slow-moving warm front across parts of south GA into far
southern SC. Enhanced low-level SRH along the boundary may support a
few transient supercell structures persisting this evening. Bulk of
this convection should diminish though and/or shift off the Lower
Savannah Valley and coastal SC by early morning. A brief tornado and
localized damaging winds are the primary hazards.

Afternoon guidance continued to signal scattered convection
redeveloping later tonight through mid-morning Sunday from portions
of the northeast Gulf across the FL Panhandle and southeast AL into
far southwest GA along a north-south/oriented confluence band. This
will be aided by strengthening upper-level diffluence downstream of
a jetlet ejecting into the central Gulf. Given the meridional
deep-layer flow regime, largely paralleling the axis of storm
development, heavy rain is likely the primary threat (reference WPC
ERO). Near-saturated thermodynamic profiles coupled with adequate
low-level SRH suggests a brief tornado and locally damaging winds
will remain possible through 12Z.

...Northern Rockies...
A fairly prolific number of severe gusts have been measured this
evening with a swath of high-based convection across southeast ID
into central MT. With limited downstream instability, this activity
should diminish after sunset. Until that time, sporadic severe gusts
will be possible.

..Grams.. 05/11/2025

$$

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ACUS01 KWNS 110543
SWODY1
SPC AC 110542

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1242 AM CDT Sun May 11 2025

Valid 111200Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST ID
TO CENTRAL/EASTERN MT...

...SUMMARY...
Scattered severe gusts are possible across a part of the Northwest
from mid-afternoon into the evening. Isolated severe thunderstorms
are also possible across the Southeast today through tonight.

...Northern Rockies/High Plains and northeast Great Basin...
A broad upper trough, consisting of multiple embedded shortwave
impulses, will largely remain anchored off the BC and Pacific
Northwest Coast. A fast mid-level jet, in excess of 70 kts at 500
mb, will overspread northern CA today and expand towards the
northern Rockies through 12Z Monday. Displaced northeast of this
strong flow regime, a broad swath of isolated to scattered
thunderstorms is expected to peak during the late afternoon and
early evening.

Similar to Sunday, sporadic severe gusts appear to be the primary
hazard owing to deeply mixed boundary layers, especially with
eastern extent from southeast ID to central/eastern MT. Pockets of
modest buoyancy, coupled with moderate to strong deep-layer
southwesterly speed shear, could yield a few high-based supercell
structures producing small to marginally severe hail. This should be
focused from the OR/WA/ID border area into central MT, and
separately over southeast ID into Yellowstone. These structures may
further aid in the downstream severe wind threat in MT.

...Southeast...
A mid/upper cyclone will drift east across the Sabine to Lower MS
Valleys through early Monday. The belt of stronger mid/upper flow
will largely remain centered over the northeast Gulf Coast, with
weaker branches curling northwest towards the Mid-South and the
other continuing across the South Atlantic Coast.

Thunderstorm clusters are expected to be ongoing across the
northeast Gulf through the FL Panhandle into southeast AL/southwest
GA and near coastal SC. The primary concern with the Panhandle to
Chattahoochee Valley convection is for potential of a tornado or two
and locally damaging winds through late morning. A 30-40 kt
low-level jet is expected to sustain adequately enlarged low-level
hodographs, especially towards the coast. But convection is expected
to be within a messy, outflow-dominated mode by 12Z given
near-parallel alignment of the deep-layer shear vector and initial north/south-oriented convective swath. More widespread convection
should form along large-scale outflow into the afternoon, which will
tend to push east-northeast, and sea breeze boundaries. Downstream
wind profiles appear less favorable for organized storms. Weak
mid-level lapse rates should further marginalize/maintain an
isolated severe threat towards the South Atlantic States.

Farther west in AL to MS, despite somewhat cooler mid-level
temperatures closer to the upper cyclone, lapse rates still appear
modest. But deep-layer speed shear will be moderately favorable amid
a nearly unidirectional southeasterly wind profile. A few cells may
briefly produce marginally severe hail and locally strong gusts,
mainly from late afternoon into mid-evening.

..Grams/Lyons.. 05/11/2025

$$

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ACUS01 KWNS 111255
SWODY1
SPC AC 111254

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 AM CDT Sun May 11 2025

Valid 111300Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN ROCKIES AND MONTANA HIGH PLAINS...

...SUMMARY...
Scattered severe wind gusts are expected across the northern Rockies
to Montana High Plains fom mid-afternoon into the evening. Isolated
severe thunderstorms are also possible across the Southeast today
through tonight.

...Northern Rockies/High Plains and northeast Great Basin...
The leading portion of an eastward-transitioning upper-level trough
will overspread the northern Rockies and northern Great Basin later
today and tonight, with preceding height falls and a regionally
strengthening 60-80 kt southwesterly mid-level jet. These trends in
conjunction with orographic influences/differential heating will
lead to another round of isolated to scattered thunderstorms by
mid/late afternoon.

Similar to Saturday, severe-caliber wind gusts will be the primary
hazard as storms develop in association with deeply mixed boundary
layers, especially with eastward extent from southeast Idaho to
central/eastern Montana. Corridors of modest buoyancy, coupled with
moderate to strong deep-layer southwesterly speed shear, could yield
a few high-based supercell structures producing small to marginally
severe hail. This should be focused from the Oregon/Washington/Idaho
border vicinity into central Montana, and separately over southeast
Idaho into Yellowstone.

...Southeast States...
A persistent, slow-moving, and essentially vertically stacked low
will persist, centered over the ArkLaMiss vicinity, with a preceding
belt of moderately strong mid-level winds extending over the
northeast Gulf to the coastal Southeast. This will overlie a
moderately moist warm sector to the east of the surface cyclone and
along/south of the eastward-extending stationary front (or
slow-moving warm front).

Scattered thunderstorms are ongoing regionally this morning,
including semi-extensively over the northeast Gulf. A 30-40 kt
southerly low-level jet is expected to sustain adequately enlarged
low-level hodographs within this corridor, but especially towards
the coast and near the warm front. But convection is expected to be
within a messy, outflow-dominated mode at times. Regardless,
isolated damaging wind and tornado potential is apparent. While the
severe risk does not appear as semi-focused as yesterday, portions
of far northern Florida to southern/southeast Georgia in vicinity of
the stationary/warm front will be reevaluated for a potential Slight
Risk upgrade.

Farther west in Alabama and Mississippi, despite somewhat cooler
mid-level temperatures closer to the upper cyclone, lapse rates
still appear modest. But deep-layer speed shear will be moderately
favorable amid a nearly unidirectional southeasterly wind profile. A
few cells may briefly produce marginally severe hail and locally
strong gusts, and possibly some funnel/brief tornado potential,
mainly from late afternoon through early/mid-evening.

..Guyer/Dean.. 05/11/2025

$$

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ACUS01 KWNS 111620
SWODY1
SPC AC 111619

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1119 AM CDT Sun May 11 2025

Valid 111630Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN ROCKIES AND MONTANA HIGH PLAINS...

...SUMMARY...
Scattered severe wind gusts are expected across the northern Rockies
to Montana High Plains from mid-afternoon into the evening. Isolated
severe thunderstorms are also possible across the Southeast today
through tonight.

...Northern Rockies/High Plains and northeast Great Basin...
Strengthening southwesterly flow aloft is anticipated throughout the
day as the upper low off the Pacific Northwest coast progresses
eastward and a lead shortwave trough pivots through OR/northern CA
into the northern Rockies. Strong heating will help destabilize the
airmass downstream from the northern Rockies into the northern High
Plains. Large-scale ascent attendant to the approaching shortwave
trough, coupled with orographic lift, will help initiate storms
across the high terrain during the afternoon within this
destabilized airmass.

Environmental conditions suggest some supercells are possible with
this initial development, with damaging gusts and isolated hail as
the primary risk. A low-probability corridor of tornado potential
exists across southeast ID. The storms should encounter an
increasingly mixed environment with eastern/northeastern extent into
central MT, with strong gusts becoming the primary severe hazard as
storms trend towards more outflow-dominant linear structures.

...Southeast States...
Recent satellite imagery and surface observations continue to show
the vertically stacked low over the Lower MS Valley, with broad
swath of southwesterly flow extending south and east of this low
from the central Gulf into FL. Surface features have become
increasingly diffuse across the Southeast and FL over the past two
days given the persistence of this low and associated precipitation,
but recent surface analysis shows a weak and wavy stationary
boundary extending from the low over the ArkLaMiss southeastward to
the AL/FL Panhandle border before arcing back northeastward across
southern GA.

Scattered thunderstorms are ongoing and the general expectation is
for scattered to numerous thunderstorms to persist across much of
the region throughout the day. Widespread cloudiness should limit
heating, but ample low-level moisture will still support modest
buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some
transient storm organization, but in general convection is expected
to be disorganized, outflow-dominated multicells. Even so, isolated
damaging gusts are possible. Some low-probability tornado potential
exists as well, particularly along the stationary boundary across
southern GA around 00Z.

Farther northwest across AL/MS and into eastern AR, the airmass is
forecast to destabilize this afternoon as heating occurs beneath
cool temperatures aloft. Even with the cooler temperature aloft,
overall buoyancy will be modest given the somewhat cool low to
mid-level thermodynamic profile. Even so, a nearly unidirectional
southeasterly wind profile with moderate deep-layer speed shear
could support brief updraft organization. As a result, a few cells
may briefly produce marginally severe hail and locally strong gusts,
and possibly some funnel/brief tornado potential, from late
afternoon through early/mid-evening.

..Mosier/Wendt.. 05/11/2025

$$

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ACUS01 KWNS 112000
SWODY1
SPC AC 111959

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Sun May 11 2025

Valid 112000Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN ROCKIES/GREAT BASIN AND MONTANA HIGH PLAINS...

...SUMMARY...
Scattered severe wind gusts are expected across the northern
Rockies/Great Basin and the Montana High Plains from mid-afternoon
into the evening. Isolated severe thunderstorms are also possible
across the Southeast today through tonight.

...20Z Update...
The only noteworthy change with this update was a southwestward
expansion of the Slight Risk area into northern UT, driven by
15-percent severe wind probabilities. Here, ample diurnal heating
has resulted in a deep/dry boundary layer supportive of scattered
severe wind gusts accompanying high-based storms. Reference Severe
Thunderstorm Watch #245 for more details. Farther east, isolated
severe storms capable of producing locally damaging winds and
marginally severe hail remain possible across the Southeast into
this evening. Reference MCDs #766/767 for details.

..Weinman.. 05/11/2025

.PREV DISCUSSION... /ISSUED 1119 AM CDT Sun May 11 2025/

...Northern Rockies/High Plains and northeast Great Basin...
Strengthening southwesterly flow aloft is anticipated throughout the
day as the upper low off the Pacific Northwest coast progresses
eastward and a lead shortwave trough pivots through OR/northern CA
into the northern Rockies. Strong heating will help destabilize the
airmass downstream from the northern Rockies into the northern High
Plains. Large-scale ascent attendant to the approaching shortwave
trough, coupled with orographic lift, will help initiate storms
across the high terrain during the afternoon within this
destabilized airmass.

Environmental conditions suggest some supercells are possible with
this initial development, with damaging gusts and isolated hail as
the primary risk. A low-probability corridor of tornado potential
exists across southeast ID. The storms should encounter an
increasingly mixed environment with eastern/northeastern extent into
central MT, with strong gusts becoming the primary severe hazard as
storms trend towards more outflow-dominant linear structures.

...Southeast States...
Recent satellite imagery and surface observations continue to show
the vertically stacked low over the Lower MS Valley, with broad
swath of southwesterly flow extending south and east of this low
from the central Gulf into FL. Surface features have become
increasingly diffuse across the Southeast and FL over the past two
days given the persistence of this low and associated precipitation,
but recent surface analysis shows a weak and wavy stationary
boundary extending from the low over the ArkLaMiss southeastward to
the AL/FL Panhandle border before arcing back northeastward across
southern GA.

Scattered thunderstorms are ongoing and the general expectation is
for scattered to numerous thunderstorms to persist across much of
the region throughout the day. Widespread cloudiness should limit
heating, but ample low-level moisture will still support modest
buoyancy. Shear will gradually increase as the low to mid-level flow strengthens this afternoon and evening, which could lead to some
transient storm organization, but in general convection is expected
to be disorganized, outflow-dominated multicells. Even so, isolated
damaging gusts are possible. Some low-probability tornado potential
exists as well, particularly along the stationary boundary across
southern GA around 00Z.

Farther northwest across AL/MS and into eastern AR, the airmass is
forecast to destabilize this afternoon as heating occurs beneath
cool temperatures aloft. Even with the cooler temperature aloft,
overall buoyancy will be modest given the somewhat cool low to
mid-level thermodynamic profile. Even so, a nearly unidirectional
southeasterly wind profile with moderate deep-layer speed shear
could support brief updraft organization. As a result, a few cells
may briefly produce marginally severe hail and locally strong gusts,
and possibly some funnel/brief tornado potential, from late
afternoon through early/mid-evening.

$$

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ACUS01 KWNS 120045
SWODY1
SPC AC 120043

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0743 PM CDT Sun May 11 2025

Valid 120100Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT AND
WESTERN ND...

...SUMMARY...
Isolated to scattered severe wind gusts may persist across parts of
the northern Great Plains this evening but will subside tonight. A low-probability wind/tornado threat remains apparent across
central/south Alabama to the Florida Panhandle into Monday morning.

...Northern Great Plains/Rockies...
Isolated to widely scattered thunderstorms are ongoing across parts
of the Rockies and northern Great Plains. The most likely corridor
for severe gusts appears to be from eastern MT through western ND
where surface temperature-dew point spreads of 45-55 F remain
common. This activity will diminish after sunset, with the severe
wind threat expected to cease towards late evening.

Farther west in the ID Panhandle to northwest MT, a supercell or two
remains possible the northern Rockies, within the left-exit region
of a strengthening mid-level jet. Meager buoyancy will be the
primary limiting factor, but small to marginally severe hail is
possible within the post-frontal convective regime.

...Southeast...
Overall severe potential has been limited today, despite extensive
convective activity. Will continue a low-probability severe area
ahead of an arc of slow-moving storms over southwest AL. Bulk of
guidance suggests slight strengthening of mid-level southerlies will
occur across the FL Panhandle and the southeast AL/southwest GA
vicinity tonight, downstream of the nearly-stationary low over LA.
This may foster maintenance of transient supercell structures atop
surface east-southeasterly winds. Weak buoyancy and mid-level lapse
rates will limit overall tornado/wind potential. Elsewhere,
localized strong gusts may still occur from the FL Peninsula towards
the GA/SC coast through the overnight.

..Grams.. 05/12/2025

$$

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ACUS01 KWNS 120524
SWODY1
SPC AC 120523

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1223 AM CDT Mon May 12 2025

Valid 121200Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE SOUTHEAST
AND NORTHEAST MT/NORTHWEST ND...

...SUMMARY...
Isolated severe thunderstorms are possible across parts of the
Southeast today. A tornado or two, localized damaging winds, and
hail are possible. Isolated severe gusts are also possible in
northeast Montana to northwest North Dakota around early evening.

...Southeast...
The vertically stacked mid/upper low that has been nearly stationary
over the Sabine Valley will finally pivot northeastward towards
western TN through early Tuesday. A jetlet of strong mid-level
southerlies over the northeast Gulf and FL Panhandle will dampen
somewhat as it becomes centered on north FL to southeast GA vicinity
this afternoon. More probable diurnal thunderstorm development is
anticipated from the left-exit region of this jetlet westward
towards the cold-core of the stacked low. Deep-layer vertical shear
will relax with westward extent, yielding more of a pulse
strong-storm environment from Middle TN to western AL and MS.
Despite the meridional deep-layer wind profile, effective values
should be sufficient for multicell clusters and transient updraft
rotation centered on eastern AL and GA into north FL. Pockets of
modest buoyancy should support a mix of small to marginally severe
hail and strong gusts capable of isolated damaging winds. Along the
eastern periphery of this activity, a tornado or two is possible
where there remains some overlap with the western belt of enhanced
low-level flow, shifting east along the South Atlantic Coast.

Farther south, a more nebulous convective scenario is anticipated
amid extensive ongoing convection across the FL Peninsula and Keys.
Guidance differs markedly with the degree of destabilization, as
adequate boundary-layer heating will be required amid poor mid-level
lapse rates near 5 C/km. Some guidance suggests south FL has the
best chance at recovery by afternoon. As such, have opted to
maintain the level 1-MRGL risk through the entire region, mainly
driven by wind.

...Northeast MT to northwest ND...
Another day of rather deeply mixed thermodynamic profiles is
expected across this portion of the Upper MO Valley. Convective
coverage off the higher terrain of southern MT should be
substantially less than in recent days, amid deep-layer
southwesterly wind profiles. Some guidance suggests very isolated
storms could develop as low-level convergence increases in the early
evening. Should this occur, potential will exist for a few dry
microbursts producing localized severe gusts.

..Grams/Lyons.. 05/12/2025

$$

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ACUS01 KWNS 121243
SWODY1
SPC AC 121241

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0741 AM CDT Mon May 12 2025

Valid 121300Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
MONTANA AND NORTHWEST NORTH DAKOTA...

...SUMMARY...
Isolated severe thunderstorms are possible across parts of the
Southeast today, where a tornado or two, localized damaging winds,
and hail could occur. Isolated severe wind gusts are also possible
in northeast Montana to northwest North Dakota around early evening.

...Southeast States...
The persistent vertically stacked mid/upper low that has been nearly
stationary over the Sabine Valley/Lower Mississippi River Valley
will finally accelerate northeastward towards western Tennessee
through tonight. A jetlet of cyclonically curved mid-level
southerlies over the northeast Gulf and Florida Panhandle will
dampen somewhat as it becomes centered on north Florida to southeast
Georgia vicinity this afternoon. More probable diurnal thunderstorm
development is anticipated from the left-exit region of this jetlet
westward towards the cold-core of the stacked low.

Deep-layer vertical shear will relax with westward extent, yielding
more of a pulse strong-storm environment from Middle Tennessee to
western Alabama and Mississippi. Despite the meridional deep-layer
wind profile, effective shear should be sufficient for multicell
clusters and transient updraft rotation centered on eastern Alabama
and Georgia into north Florida. Pockets of modest buoyancy should
support a mix of small to marginally severe hail and strong gusts
capable of isolated damaging winds. Along the eastern periphery of
this activity, a tornado or two is possible where there remains some
overlap with the western belt of enhanced low-level flow, including
South Carolina into both western and near-coastal North Carolina.

Farther south, a more nebulous convective scenario is anticipated
amid extensive ongoing convection across the Florida Peninsula and
Keys. Guidance differs markedly with the degree of destabilization,
as adequate boundary-layer heating will be required amid poor
mid-level lapse rates near 5 C/km. But some guidance suggests south-central/southern Florida has the best chance at recovery by
afternoon, although low-level winds will tend to be veering with a
likely diminishing trend of low-level SRH.

...Northeast Montana/northwest North Dakota...
Another day of rather deeply mixed thermodynamic profiles is
expected across the region. Isolated thunderstorms are most probable
from mid-afternoon into evening with development near/behind an eastward-advancing front. Overall convective coverage off the higher
terrain of southern Montana should be substantially less than in
recent days, amid deep-layer southwesterly wind profiles. The
potential will exist for a few dry microbursts producing localized severe-caliber wind gusts.

..Guyer/Dean.. 05/12/2025

$$

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ACUS01 KWNS 121631
SWODY1
SPC AC 121630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Mon May 12 2025

Valid 121630Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
MONTANA AND NORTHWEST NORTH DAKOTA...

...SUMMARY...
Isolated severe thunderstorms are possible across parts of the
Southeast today, where a tornado or two, localized damaging winds,
and hail could occur. Isolated severe wind gusts are also possible
in northeast Montana to northwest North Dakota around early evening.

...Southeast...
Vertically stacked cyclone persists over the Mid-South this morning. Expectation is for this system to become more progressive today,
ejecting into western TN by early tomorrow morning. A moist airmass
remains in place downstream of this cyclone across the Southeast,
and numerous showers and thunderstorms are currently ongoing within
the warm conveyor of this system from FL into GA and the Carolina.
Moderate southwesterly/southerly will persist within this warm
sector, and effective shear should be sufficient for multicell
clusters and transient updraft rotation. However, only modest
destabilization is anticipated across much of the region, limiting
the overall severe potential. Expectation is for occasionally strong
storms in areas of sufficient destabilization, with damaging
downbursts and hail as the primary risk. A corridor of greater
severe potential could be developing across southern GA and northern
FL where some heating is occurring.

...Northeast Montana/northwest North Dakota...
Deep shortwave trough will continue to push eastward across the
Pacific Northwest today, with associated southwesterly flow aloft
extending from northern CA into the northern High Plains. Deeply
mixed thermodynamic profiles are expected across the region as the
airmass destabilizes this afternoon. Isolated thunderstorms are most
probable from mid-afternoon into evening with development
near/behind an eastward-advancing front. Convective coverage off the
higher terrain of southern Montana should be less than in recent
days. However, the potential will still exist for a few dry
microbursts producing localized severe-caliber wind gusts as the
storms move off the terrain into more of eastern MT.

..Mosier/Halbert.. 05/12/2025

$$

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ACUS01 KWNS 122000
SWODY1
SPC AC 121959

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Mon May 12 2025

Valid 122000Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
MONTANA AND NORTHWEST NORTH DAKOTA...PORTIONS OF THE SOUTHEAST...

...SUMMARY...
Isolated severe thunderstorms are possible across parts of the
Southeast today, where a tornado or two, localized damaging winds,
and hail could occur. Isolated severe wind gusts are also possible
in northeast Montana to northwest North Dakota around early evening.

...20Z Update...
Minor adjustments were made in the Southeast based on observed
convective trends. Greater buoyancy has developed in southeast to
east-central Georgia. This zone could have locally higher potential
for strong to severe storms. However, mid-level dry air is evident
on water vapor imagery. Updrafts may tend to struggle to intensify
due to dry air entrainment. Elsewhere, the forecast remains
unchanged.

..Wendt.. 05/12/2025

.PREV DISCUSSION... /ISSUED 1130 AM CDT Mon May 12 2025/

...Southeast...
Vertically stacked cyclone persists over the Mid-South this morning. Expectation is for this system to become more progressive today,
ejecting into western TN by early tomorrow morning. A moist airmass
remains in place downstream of this cyclone across the Southeast,
and numerous showers and thunderstorms are currently ongoing within
the warm conveyor of this system from FL into GA and the Carolina.
Moderate southwesterly/southerly will persist within this warm
sector, and effective shear should be sufficient for multicell
clusters and transient updraft rotation. However, only modest
destabilization is anticipated across much of the region, limiting
the overall severe potential. Expectation is for occasionally strong
storms in areas of sufficient destabilization, with damaging
downbursts and hail as the primary risk. A corridor of greater
severe potential could be developing across southern GA and northern
FL where some heating is occurring.

...Northeast Montana/northwest North Dakota...
Deep shortwave trough will continue to push eastward across the
Pacific Northwest today, with associated southwesterly flow aloft
extending from northern CA into the northern High Plains. Deeply
mixed thermodynamic profiles are expected across the region as the
airmass destabilizes this afternoon. Isolated thunderstorms are most
probable from mid-afternoon into evening with development
near/behind an eastward-advancing front. Convective coverage off the
higher terrain of southern Montana should be less than in recent
days. However, the potential will still exist for a few dry
microbursts producing localized severe-caliber wind gusts as the
storms move off the terrain into more of eastern MT.

$$

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ACUS01 KWNS 130030
SWODY1
SPC AC 130029

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0729 PM CDT Mon May 12 2025

Valid 130100Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE SAVANNAH
VALLEY TO THE COASTAL CAROLINAS...AND IN NORTHEAST MT TO FAR
NORTHWEST ND...

...SUMMARY...
Isolated severe thunderstorms remain possible tonight from the
Savannah Valley to the coastal Carolinas, and through the rest of
this evening in northeast Montana to far northwest North Dakota.

...Savannah Valley to the coastal Carolinas...
Potential for strong to severe storms will remain limited across the
Southeast tonight. One area of low-probability tornado/wind threat
that may persist is downstream of an arc of ongoing convection
across eastern GA to upstate SC. While downstream instability is
weak, enough of a gap exists between this arc and the persistent
warm-conveyor rain swath across eastern NC. Adequate low to
deep-layer shear should be maintained for transient weak rotation
through 12Z Tuesday. This might support a brief tornado or localized
wet microburst. These threats should tend to become more confined
towards the SC to southern NC coastal plain overnight.

...Northeast MT and far northwest ND...
High-based convection persists along and rearward of an undercutting
Pacific cold front marching east into northeast MT. Despite meager
MLCAPE, as sampled by the 00Z GGW sounding, 45-55 F surface
temperature-dew points spreads ahead of the front will promote
potential for a few gusts of 55-70 mph through late evening.

..Grams.. 05/13/2025

$$

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ACUS01 KWNS 130554
SWODY1
SPC AC 130553

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1253 AM CDT Tue May 13 2025

Valid 131200Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE NC/VA/WV VICINITY...NORTHERN GREAT PLAINS...AND DEEP SOUTH...

...SUMMARY...
Isolated severe thunderstorms are possible: 1) today in vicinity of Virginia-North Carolina-West Virginia, 2) during the late afternoon
to mid-evening over a portion of the Deep South, and 3) this evening
into early morning Wednesday in parts of the northern Great Plains.

...NC/VA/WV vicinity...
A mid/upper trough centered on the Mid to Deep South will gradually
shift east-northeastward, reaching the OH Valley to FL Peninsula by
early Wednesday. The low-level warm conveyor will remain displaced
well downstream across eastern NC and advance north across the
Mid-Atlantic States towards the Lower Great Lakes. Early-day severe
potential will be tied to this conveyor in eastern NC/VA where
low-topped convection is anticipated. While instability will remain
quite limited, enlarged low-level hodograph curvature and
near-saturated thermodynamic profiles will offer potential for a
brief tornado.

West of the warm conveyor, more pronounced boundary-layer heating
will occur, likely resulting in moderate buoyancy by early to mid
afternoon with MLCAPE of 1000-1500 J/kg. This coupled with weak
mid-level height falls should support scattered thunderstorms.
Deep-layer shear is expected to remain moderate across the Piedmont,
with decreasing values westward towards the trough. This renders a
nebulous transition between loosely organized to pulse convection.
For now, have delineated the MRGL risk where at least modest values
of deep-layer shear could support multicell clusters. Isolated
severe hail and damaging winds are the expected hazards, west of the
coastal plain.

...AL/MS/TN vicinity...
Some guidance suggests a supercell or two may develop on the
backside of the departing mid-level trough. A mesoscale corridor of differential boundary-layer heating, coincident with the eastward
expansion of the southern Great Plains EML across the Lower MS
Valley, may support a favored corridor for late afternoon to
mid-evening storm development. Despite weak low-level winds, some
veering of the wind profile should yield modest hodograph curvature.
This coupled with moderate mid-level west-northwesterlies will favor
a conditional supercell threat.

...Northern Great Plains...
A broad, but more amplified mid/upper trough will gradually shift
east across the West. A downstream split in the stronger flow regime
is expected over the southern Rockies to adjacent High Plains in the
wake of the prior blocking pattern over the central states. This
will yield a meridional mid/upper wind profile across the northern
Great Plains. At the surface, a Pacific cold front will stall in the
western to central Dakotas vicinity. Strong mid/upper winds will
remain displaced west of this boundary, where strengthening
large-scale ascent is anticipated tonight as an embedded shortwave
impulse rotates through the eastern portion of the western trough.

Elevated buoyancy is expected to remain weak given poor-quality
low-level moisture. Still, with the strengthening effective bulk
shear and forcing for ascent, a few elevated supercells are possible
tonight into early morning Wednesday. Isolated severe hail should be
the primary hazard, with potential for strong (but sub-severe) gusts
closer to the surface front.

..Grams/Lyons.. 05/13/2025

$$

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ACUS01 KWNS 131252
SWODY1
SPC AC 131250

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0750 AM CDT Tue May 13 2025

Valid 131300Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE MID-ATLANTIC...NORTHERN GREAT PLAINS...AND DEEP SOUTH...

...SUMMARY...
Isolated severe thunderstorms are possible: 1) today in vicinity of Virginia-North Carolina-West Virginia, 2) during the late afternoon
to mid-evening over a portion of the Deep South, and 3) this evening
into early morning Wednesday in parts of the northern Great Plains.

...NC/VA/WV vicinity...
The upper-level low centered near the mid-Mississippi Valley will
continue to lift east/northeast through tonight, as a notable
shortwave trough rotates northeast across the Mid-Atlantic region.
Generally weak surface-based instability (MLCAPE at or below 1000
J/kg) will exist across the coastal plain as a belt of stronger 850
mb flow lifts northeast across eastern sections of NC/VA. This will
contribute to enlarged low-level hodograph structures and support
the continued potential for transient areas of rotation and a few
short-lived tornadoes associated with stronger convective elements.
See recently issued Mesoscale Discussion 774 for details on
short-term convective trends.

Farther west into WV/western VA and NC, subtle large-scale forcing
for ascent with the approaching upper low will contribute to
thunderstorm development. Although deep-layer shear will tend to
relax with westward extent, slightly more favorable mid-level lapse
rates and 1000-locally 1500 J/kg MLCAPE will result in the potential
for isolated strong/severe gusts and hail.

...AL/MS/TN vicinity...
Some hi-res guidance continues to suggest a supercell or two may
develop to the west of the departing mid-level trough, where a
corridor of differential boundary-layer heating may support a
favored zone for late afternoon through mid-evening storm
development. Some veering of the wind profile should yield modest
hodograph curvature. This, coupled with moderate mid-level
west-northwesterly flow, will favor a conditional supercell threat.

...Northern Great Plains...
An upstream upper-level trough over the western U.S. will move
steadily east, resulting in strengthening southerly mid-level flow
across the northern Plains. A Pacific cold front will make modest
eastward progress today before becoming quasi-stationary across the western/central Dakotas, however the stronger mid-level flow will
remain generally displaced to the west. Weak elevated buoyancy and
sufficient deep-layer shear may still result in scattered storms,
including supercells, with potential for severe hail. Some risk for strong/severe gusts may also exist with storms closer to the surface
front.

..Bunting/Dean.. 05/13/2025

$$

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ACUS01 KWNS 131623
SWODY1
SPC AC 131622

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1122 AM CDT Tue May 13 2025

Valid 131630Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH CAROLINA INTO THE SOUTHERN MID-ATLANTIC...CENTRAL GULF COAST
STATES...AND NORTHERN PLAINS...

...SUMMARY...
Isolated strong to severe thunderstorms appear possible today and
tonight across parts of North Carolina into the southern
Mid-Atlantic, central Gulf Coast states, and northern Plains.

...North Carolina into the Southern Mid-Atlantic...
A closed mid/upper-level low will continue to slowly meander from
the TN Valley towards the central Appalachians through the period.
An embedded mid-level shortwave trough will rotate northward across
the Carolinas into the southern Mid-Atlantic by this evening.
Stronger low/mid-level flow will tend to remain across the eastern
Carolinas into southern VA today, with generally weaker winds aloft
in closer proximity to the mid/upper low. A moist low-level airmass
will remain in place over much of the Carolinas, central
Appalachians, and southern Mid-Atlantic. But, poor mid-level lapse
rates will tend to limit any more than weak instability from
developing through this afternoon. Deep-layer shear away from the
coast will also tend to remain muted, which should keep overall
thunderstorm organization modest. Even with these forecast
thermodynamic and kinematic limitations, some organization may occur
with thunderstorms that develop and spread northward this afternoon.
Isolated damaging winds appear to be the main threat with any
loosely organized clusters that can form, but marginally severe hail
could also occur with the strongest cores. A tornado or two also
appears possible along a pseudo-warm front across northeast NC into
southeast VA and vicinity, where low-level flow and shear are
forecast to be modestly enhanced compared to locations farther west.

...Mississippi/Alabama...
Morning showers and related cloudiness will temper diurnal
destabilization to some extent across northern MS/AL this afternoon.
But, renewed thunderstorm development still appears possible later
today across this region, on the southern fringe of the slowly
moving mid/upper low. Weak low-level westerly winds are expected to
veer to northwesterly and gradually strengthen with height though
mid levels. Related 30-40 kt of deep-layer shear will conditionally
support organized updrafts, including the potential for a supercell
with an associated hail/wind threat. The overall severe risk should
remain quite isolated, which warrants maintaining the Marginal Risk
with this update.

...Northern Plains...
An amplified mid/upper-level trough will move eastward over the
western states through tonight. A surface cold front is forecast to
decelerate and eventually stall over parts of the Dakotas by this
evening. Stronger mid/upper-level flow is expected to remain
displaced to the west of this surface boundary. Even so, there are
some indications in guidance that elevated thunderstorms posing a
threat for isolated hail may impact parts of the northern Plains
this evening into tonight. Weak instability should tend to limit the
overall severe threat.

..Gleason/Wendt.. 05/13/2025

$$

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ACUS01 KWNS 131952
SWODY1
SPC AC 131950

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0250 PM CDT Tue May 13 2025

Valid 132000Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH CAROLINA INTO THE SOUTHERN MID-ATLANTIC...CENTRAL GULF COAST
STATES...AND THE NORTHERN HIGH PLAINS...

...SUMMARY...
Marginally severe thunderstorms will be possible from this afternoon
into tonight across parts of North Carolina, the Mid-Atlantic,
central Gulf Coast states, and northern High Plains.

...DISCUSSION...
No change is made to the outlook for this issuance.

..Broyles.. 05/13/2025

.PREV DISCUSSION... /ISSUED 1122 AM CDT Tue May 13 2025/

...North Carolina into the Southern Mid-Atlantic...
A closed mid/upper-level low will continue to slowly meander from
the TN Valley towards the central Appalachians through the period.
An embedded mid-level shortwave trough will rotate northward across
the Carolinas into the southern Mid-Atlantic by this evening.
Stronger low/mid-level flow will tend to remain across the eastern
Carolinas into southern VA today, with generally weaker winds aloft
in closer proximity to the mid/upper low. A moist low-level airmass
will remain in place over much of the Carolinas, central
Appalachians, and southern Mid-Atlantic. But, poor mid-level lapse
rates will tend to limit any more than weak instability from
developing through this afternoon. Deep-layer shear away from the
coast will also tend to remain muted, which should keep overall
thunderstorm organization modest. Even with these forecast
thermodynamic and kinematic limitations, some organization may occur
with thunderstorms that develop and spread northward this afternoon.
Isolated damaging winds appear to be the main threat with any
loosely organized clusters that can form, but marginally severe hail
could also occur with the strongest cores. A tornado or two also
appears possible along a pseudo-warm front across northeast NC into
southeast VA and vicinity, where low-level flow and shear are
forecast to be modestly enhanced compared to locations farther west.

...Mississippi/Alabama...
Morning showers and related cloudiness will temper diurnal
destabilization to some extent across northern MS/AL this afternoon.
But, renewed thunderstorm development still appears possible later
today across this region, on the southern fringe of the slowly
moving mid/upper low. Weak low-level westerly winds are expected to
veer to northwesterly and gradually strengthen with height though
mid levels. Related 30-40 kt of deep-layer shear will conditionally
support organized updrafts, including the potential for a supercell
with an associated hail/wind threat. The overall severe risk should
remain quite isolated, which warrants maintaining the Marginal Risk
with this update.

...Northern Plains...
An amplified mid/upper-level trough will move eastward over the
western states through tonight. A surface cold front is forecast to
decelerate and eventually stall over parts of the Dakotas by this
evening. Stronger mid/upper-level flow is expected to remain
displaced to the west of this surface boundary. Even so, there are
some indications in guidance that elevated thunderstorms posing a
threat for isolated hail may impact parts of the northern Plains
this evening into tonight. Weak instability should tend to limit the
overall severe threat.

$$

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ACUS01 KWNS 140101
SWODY1
SPC AC 140100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Tue May 13 2025

Valid 140100Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
NORTH CAROLINA AN EASTERN VIRGINIA AND FROM NORTHEAST WYOMING AND
SOUTHEAST MONTANA INTO THE WESTERN DAKOTAS...

...SUMMARY...
Marginally severe thunderstorms remain possible this evening across
eastern North Carolina and eastern Virginia and northern High
Plains.

...Discussion...
The thunderstorms have ended across the marginal in Mississippi and
Alabama and additional development is not anticipated given waning
daylight and a cooling boundary layer.

A few strong to severe storms remain possible across eastern North
Carolina and the Mid-Atlantic. This threat should remain for a few
more hours before ending later this evening. A moist, unstable
environment remains along the North Carolina coast this evening with
a threat for a stronger storm or two into the overnight period.

An amplified mid/upper-level trough will move eastward over the
western states tonight. A surface cold front has stalled across
central North Dakota and western South Dakota this evening. Stronger mid/upper-level flow is expected to remain displaced to the west of
this surface boundary. Even so, there are some indications in
guidance that elevated thunderstorms posing a threat for isolated
hail may occur west of this boundary tonight. Weak instability
should tend to limit the overall severe threat.

..Bentley.. 05/14/2025

$$

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ACUS01 KWNS 140550
SWODY1
SPC AC 140549

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1249 AM CDT Wed May 14 2025

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
NEBRASKA...THE EASTERN DAKOTAS...FAR NORTHWEST IOWA...AND FAR
SOUTHWEST MINNESOTA...

...SUMMARY...
Scattered strong to severe thunderstorms are possible mainly over
parts of the Dakotas and Nebraska Wednesday afternoon and evening,
and perhaps into far western Iowa and southwest Minnesota overnight.
A few strong to severe storms may occur from parts of the southern
Appalachians to the Carolinas and Mid-Atlantic Wednesday afternoon.

...Synopsis...
A broad mid-level jet will eject into the central Plains on
Wednesday with a deepening surface low moving north through the
central Plains and into the northern Plains. Farther east, a
mid-level shortwave trough will advance east from the southern
Appalachians to the western Atlantic by the end of the period.

...Northern/Central Plains...
Low-level moisture is in place across the Plains this morning with
upper 50/low 60s dewpoints in Kansas and mid 60s dewpoints across
Oklahoma. However, this moisture is very shallow with a mean mixing
ratio around 11 g/kg from the OUN, LMN, and FWD 00Z RAOBs.
Therefore, expect this moisture to advect northward through the day
given the strengthening southerly flow associated with the deepening
cyclone. However, dewpoints across Nebraska and into the Dakotas
will likely remain in the upper 50s to low 60s given the upstream
moisture quality. Nonetheless, this will be sufficient for MLCAPE
around 2000-3000 J/kg near the NE/KS border with weaker instability
farther north.

Expect storm development in the vicinity of the surface low
Wednesday afternoon where surface convergence will be maximized.
Storms may quickly develop along the frontal zone from north-central
Nebraska and into the Dakotas. These storms will pose a threat for
large hail and damaging wind gusts. Farther south, additional
development is possible along the dryline/triple point across
southwest Nebraska. These storms may have the best potential to be
discrete longer and should be supercellular given 30 to 35 knots of
shear in the region. This will also be the region with the greatest
2+ inch hail potential given the strong instability, moderate shear,
and steep lapse rates.

Low-level shear will increase after 00Z as the low-level jet
strengthens. However, by this time, expect inhibition to increase
substantially across the central Plains with storm mode becoming
more linear across northern Nebraska and into eastern South Dakota
which should limit the overall tornado threat.

...Southern Appalachians into the Carolinas and the Mid-Atlantic...
Weak to moderate instability will develop from the southern
Appalachians to the Carolinas on Wednesday. As a mid-level shortwave
trough overspreads the region, expect scattered thunderstorm
development. 25 to 30 knots of shear will support some storm
organization including potential for transient supercell structures.
In addition, modestly steep mid-level lapse rates are apparent. This
should support the potential for large hail and perhaps isolated
damaging wind gusts. Hail is expected to be the primary threat
across the region, but coverage is not expected to be high enough to
support a Slight (Level 2 out of 5) risk.

..Bentley.. 05/14/2025

$$

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ACUS01 KWNS 141250
SWODY1
SPC AC 141249

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0749 AM CDT Wed May 14 2025

Valid 141300Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE CENTRAL AND NORTHERN PLAINS...

...SUMMARY...
Scattered strong to severe thunderstorms are possible mainly over
parts of the Dakotas and Nebraska this afternoon and evening, and
far western Iowa and southwest Minnesota overnight. A few strong to
severe storms may occur from parts of the southern Appalachians to
the Carolinas and Mid-Atlantic this afternoon.

...Northern/Central Plains...
Surface low pressure will deepen in the vicinity of the CO/KS/NE
border today in response to the approach of an upper-level trough,
as an associated surface cold front moves slowly east across the central/northern Plains. Low-level moisture advection and steep
mid-level lapse rates (in excess of 8 deg C/km) will result in
MLCAPE of 2500-3000 J/kg across central NE, with weaker instability
northward across the central Dakotas. Thunderstorm development is
expected by late afternoon near the front across the Dakotas and central/northern NE, with severe hail and wind the primary risks.
Damaging winds will become more likely as one or two clusters
ultimately evolve over central/northern NE and move towards
southeast SD/southwest MN and far northwest IA during the late
evening and overnight.

Across southwest/central NE, more discrete supercell structures will
be possible with storms developing closer to the surface low/dryline intersection, with large to very large hail possible. A 5 percent
tornado probability has been introduced across portions of central
NE, where a short-duration window may exist for a couple of
tornadoes this evening with any semi-discrete storm or small cluster
in the presence of increasing low-level shear. Expected upscale
growth should limit the time frame for supercell tornado potential.


...Southern Appalachians into the Carolinas and Mid-Atlantic...
Weak to moderate instability will develop from the southern
Appalachians to the Carolinas Wednesday. As a mid-level shortwave
trough overspreads the region, scattered thunderstorms are expected
to develop. Sufficient shear of 25 to 30 knots will support some
storm organization including potential for transient supercell
structures. Modestly steep mid-level lapse rates should support the
potential for large hail and perhaps isolated damaging wind gusts.

..Bunting/Dean.. 05/14/2025

$$

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ACUS01 KWNS 141629
SWODY1
SPC AC 141628

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Wed May 14 2025

Valid 141630Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN/CENTRAL PLAINS...

...SUMMARY...
Scattered strong to severe thunderstorms should occur over parts of
the Dakotas and Nebraska this afternoon and evening, and far western
Iowa and southwest Minnesota overnight. Very large hail, severe wind
gusts, and a couple of tornadoes all appear possible.

...Northern/Central Plains...
An upper trough over the western states will pivot eastward today
while gradually acquiring a negative tilt over the northern/central
Plains by late tonight. At the surface, a front extending over the
Dakotas should stall in a nearly north-south orientation later
today. Shallow low-level moisture will continue to stream northward
this afternoon ahead of the primary surface low, which is forecast
to consolidate over western KS/southwest NE by early evening. A
dryline will extend southward from this low over much of the
central/southern Plains, but strong capping should generally limit
convective development with southward extent through much of the
day.

Daytime heating of the modestly moist low-level airmass, combined
with somewhat steepened mid-level lapse rates, will encourage around
1500-3000 J/kg of MLCAPE by mid afternoon. Stronger instability will
likely exist with southward extent into NE, where slightly greater
low-level moisture should be present. Mainly unidirectional/
southerly wind profiles along/near the front this afternoon suggest
that initial convective development will be messy, with numerous
updraft and outflow interactions. Still, the strongest of these
initial cores should pose some risk for hail and wind gusts.

Initially high-based convection is also forecast to develop across
the central High Plains (northeast CO vicinity) by late
afternoon/early evening, and spread northeastward across NE. A
greater threat for sustained supercells remains apparent with
southward extent across NE this evening, where stronger deep-layer
shear somewhat more orthogonal to the surface boundaries should be
present. Isolated very large hail (up to 2-3 inches in diameter)
will be possible with any discrete cells, while severe wind gusts
should become an increasing concern as convection grows upscale into
a bowing cluster through the evening and early overnight hours.
There should also be a narrow spatial/temporal window for a couple
of tornadoes this evening across parts of NE as a low-level jet
modestly strengthens and 0-1 km SRH increases.

...Southeast and Southern Mid-Atlantic into the Ohio Valley...
A weak mid/upper trough will drift eastward today from the
Appalachians towards the Carolinas and Mid-Atlantic. While mid-level
winds and related effective bulk shear are expected to remain rather
weak, some clustering/modest organization may occur with convection
that will further develop this afternoon across NC into parts of
southern VA. Occasional damaging winds should be the main threat
with this activity as low-level lapse rates gradually steepen with
continued diurnal heating. But, some hail may also occur. See
Mesoscale Discussion 776 for more details on the short-term severe
threat across this area.

Across parts of the OH Valley, mainly elevated thunderstorms are
forecast to develop this evening/overnight in a low-level warm
advection regime. Sufficient MUCAPE and deep-layer shear is forecast
to support an isolated threat for mainly large hail with this
activity.

..Gleason/Wendt.. 05/14/2025

$$

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ACUS01 KWNS 141945
SWODY1
SPC AC 141944

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0244 PM CDT Wed May 14 2025

Valid 142000Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE
NORTHERN/CENTRAL PLAINS...

...SUMMARY...
Scattered strong to severe thunderstorms should occur over parts of
the Dakotas and Nebraska this afternoon and evening, and far western
Iowa and southwest Minnesota overnight. Very large hail, severe wind
gusts, and a couple of tornadoes all appear possible.

...20z Update...
No changes are needed to the D1 Convective Outlook.

Severe storms are expected across the northern/central Plains this
afternoon and evening as an upper low moves eastward with a surface
cold front. Latest data from 18z RAOBs across Nebraska shows weak
mid-level capping still in place across the area near North Platte,
which much stronger MLCIN further east near Omaha. Ongoing elevated
post frontal convection will continue before further convective
development occurs later this afternoon and evening. These storms
will have potential for very large hail, damaging wind, and a couple
of tornadoes. See MCD#777 for more information on this threat in the
near term.

See previous discussion for more information below.

..Thornton/Gleason.. 05/14/2025

.PREV DISCUSSION... /ISSUED 1128 AM CDT Wed May 14 2025/

...Northern/Central Plains...
An upper trough over the western states will pivot eastward today
while gradually acquiring a negative tilt over the northern/central
Plains by late tonight. At the surface, a front extending over the
Dakotas should stall in a nearly north-south orientation later
today. Shallow low-level moisture will continue to stream northward
this afternoon ahead of the primary surface low, which is forecast
to consolidate over western KS/southwest NE by early evening. A
dryline will extend southward from this low over much of the
central/southern Plains, but strong capping should generally limit
convective development with southward extent through much of the
day.

Daytime heating of the modestly moist low-level airmass, combined
with somewhat steepened mid-level lapse rates, will encourage around
1500-3000 J/kg of MLCAPE by mid afternoon. Stronger instability will
likely exist with southward extent into NE, where slightly greater
low-level moisture should be present. Mainly unidirectional/
southerly wind profiles along/near the front this afternoon suggest
that initial convective development will be messy, with numerous
updraft and outflow interactions. Still, the strongest of these
initial cores should pose some risk for hail and wind gusts.

Initially high-based convection is also forecast to develop across
the central High Plains (northeast CO vicinity) by late
afternoon/early evening, and spread northeastward across NE. A
greater threat for sustained supercells remains apparent with
southward extent across NE this evening, where stronger deep-layer
shear somewhat more orthogonal to the surface boundaries should be
present. Isolated very large hail (up to 2-3 inches in diameter)
will be possible with any discrete cells, while severe wind gusts
should become an increasing concern as convection grows upscale into
a bowing cluster through the evening and early overnight hours.
There should also be a narrow spatial/temporal window for a couple
of tornadoes this evening across parts of NE as a low-level jet
modestly strengthens and 0-1 km SRH increases.

...Southeast and Southern Mid-Atlantic into the Ohio Valley...
A weak mid/upper trough will drift eastward today from the
Appalachians towards the Carolinas and Mid-Atlantic. While mid-level
winds and related effective bulk shear are expected to remain rather
weak, some clustering/modest organization may occur with convection
that will further develop this afternoon across NC into parts of
southern VA. Occasional damaging winds should be the main threat
with this activity as low-level lapse rates gradually steepen with
continued diurnal heating. But, some hail may also occur. See
Mesoscale Discussion 776 for more details on the short-term severe
threat across this area.

Across parts of the OH Valley, mainly elevated thunderstorms are
forecast to develop this evening/overnight in a low-level warm
advection regime. Sufficient MUCAPE and deep-layer shear is forecast
to support an isolated threat for mainly large hail with this
activity.

$$

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ACUS01 KWNS 150103
SWODY1
SPC AC 150102

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0802 PM CDT Wed May 14 2025

Valid 150100Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL AND NORTHERN PLAINS...

...SUMMARY...
Scattered strong to severe thunderstorms will occur over parts of
the Dakotas and Nebraska this evening, and across far western Iowa
and southwestern Minnesota overnight. Very large hail, severe wind
gusts, and a couple of tornadoes will be possible. A few marginally
severe storms may also occur from the Lower Ohio Valley into the
Carolinas.

...Central and Northern Plains...
The latest water vapor imagery shows a mid-level trough in the
Rockies, with a diffluent pattern over the central and northern
Plains. A pronounced dry slot is evident from the southern Rockies
into the central Plains, with multiple bands of convection ongoing
to the north of this feature. At the surface, a dual-centered 991 mb
low is over far southwest Kansas and southern Nebraska, with an
inverted trough extending north-northeastward into the eastern
Dakotas. To the west of the trough, a cold front is moving
east-southeastward across the central and northern Plains.
Thunderstorms across the Dakotas are post-frontal, while the storms
in Nebraska are straddling the boundary on both sides. These storms
are located along an axis of low-level moisture, where surface
dewpoints are in the mid to upper 50s F.

The strongest instability is located across southwestern and central
Nebraska, where temperatures have reached the lower 80s F. Across
southern Nebraska, the RAP has MLCAPE in the 2000 to 3000 J/kg
range. So far, several semi-discrete supercells have developed along
the northern edge of the strongest instability, from near North
Platte, northward into Cherry County, Nebraska. This activity is
expected to become more linear with time, as it moves
east-northeastward across the remainder of northern Nebraska and
into southeastern South Dakota. The greatest tornado potential will
exist over the next couple hours in central and northern Nebraska,
before convection becomes more linear. The latest WSR-88D VWP at
North Platte has 0-3km storm-relative helicity near 230 m2/s2.
Low-level shear should strengthen some this evening, helping to
maintain a tornado threat with supercells that remain semi-discrete.


In addition, a plume of steep mid-level lapse rates is analyzed by
the RAP from eastern Colorado into central Nebraska. Supercells at
the northeastern edge of this plume will have a large hail threat,
and hailstones of greater than 2 inches in diameter will be
possible. The wind-damage threat will likely increase as a line
segments becomes more organized later this evening. Several
short-term models suggest that a small-scale bow echo will develop
over parts of the central Plains this evening into early tonight,
where severe gusts exceeding 70 knots will be possible. The severe
threat is expected to move northeastward into parts of Iowa and
southwest Minnesota tonight.

...Lower Ohio Valley/Southern Appalachians/Carolinas...
A positively-tilted mid-level trough is currently located from the
central Appalachians southeastward into the Carolinas. At the
surface, a moist airmass is in place across much of the region, with
surface dewpoints mostly in the 60s F. Across the moist airmass, the
RAP has moderate instability analyzed from the lower Ohio Valley
southeastward into the Carolinas. Along this corridor, moderate
deep-layer shear is present according to WSR-88D VWPs, which should
be enough for a marginal severe threat for a couple more hours this
evening. Isolated severe gusts and hail will be the primary threats.

..Broyles.. 05/15/2025

$$

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ACUS01 KWNS 150601
SWODY1
SPC AC 150600

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Thu May 15 2025

Valid 151200Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
EASTERN MINNESOTA...WISCONSIN...NORTHEAST ILLINOIS...NORTHERN INDIANA...SOUTHWEST AND SOUTHERN MICHIGAN...AND FAR NORTHWEST
OHIO...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID TO UPPER MISSISSIPPI VALLEY...GREAT LAKES...OHIO VALLEY AND MID-ATLANTIC...

...SUMMARY...
Severe thunderstorms are expected across parts of the upper
Mississippi River Valley and Great Lakes this afternoon and evening.
Hailstones greater than 2 inches will be possible, along with
tornadoes with a few that could be strong. Scattered wind damage
will be likely, with wind gusts over 75 mph over parts of Lower
Michigan and northern Indiana. Isolated severe thunderstorms are
also expected through the lower Ohio River Valley, Ozarks and in
parts of the Mid-Atlantic.

...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley...
A negatively-tilted mid-level trough will move northeastward into
the Upper Midwest today, as an associated jet streak translates
eastward into the Ozarks. A secondary jet streak will move
northeastward into the mid Missouri Valley. Strong large-scale
ascent will overspread a broad moist sector from the Great Lakes
into the Ohio Valley, resulting in a widespread severe weather event
today.

At the surface, a low will consolidate and move northward across the
eastern Dakotas. A well defined warm front will advance northward
into the Wisconsin, as a cold front moves eastward into the mid to
upper Mississippi Valley. Ahead of the front, surface dewpoints from
the mid 60s to the lower 70s F will result in moderate instability
over much of the moist sector. Thunderstorms are first expected to
initiate near the mid-level low over the upper Mississippi Valley,
with storms developing south-southeastward along and ahead of the
front during the afternoon.

Indications suggest that the storms will remain somewhat spaced out,
at least early in the event. The discrete nature of the convection,
combined with moderate deep-layer shear, will be favorable for
supercell development. A broken line of severe storms is expected to
move east-northeastward into the vicinities of Milwaukee and Chicago
late this afternoon. RAP forecast soundings at 21Z along the western
shore of Lake Michigan have MLCAPE near 2000 J/kg, with 0-6 km shear
of 35 to 40 knots, and 700-500 mb lapse rates near 7.5 C/km. This
will be favorable for large hail and wind damage associated with
supercells. The more intense supercells may produce hailstones
greater than 2 inches in diameter. In addition, 0-3 km
storm-relative helicity in the 250 to 300 m2/s2 will also support
tornadoes, with the threat becoming maximized as supercells mature.
A few strong tornadoes appear likely.

Severe threat coverage will likely be maintained as a broken line
segment gradually organizes. A transition to linear mode appears
likely by early evening. Supercells and rotating elements within the
line should be capable of producing tornadoes. Wind damage will also
be likely along the leading edge of the line, with gusts over 75 mph
possible from western Lower Michigan southward into northern
Indiana. A potential for hailstones greater than 2 inches in
diameter will continue during the early evening with supercells
embedded within the line.

Further south into the lower Ohio Valley, storm coverage will be a
bit more isolated. However, cells that can develop within the
strongly unstable airmass will likely become supercells with large
hail and severe gusts. A tornado threat is also expected. It appears
that a corridor of greater severe threat will develop somewhere near
the Ohio River during the late afternoon, which could be dependent
upon the distribution and magnitude of instability.

...Ozarks/Ark-La-Tex...
Southwest mid-level flow will be in place today across the Ozarks
and Ark-La-Tex, as a jet streak moves eastward into the region. A
moist airmass will be in place to the southeast of the jet, where
surface dewpoints will be in the upper 60s and lower 70s F. By
afternoon, much of this airmass will be moderately unstable.
However, large-scale ascent to the south of the jet is forecast to
remain relatively weak, which should keep convective development
isolated. Any cell that can initiate despite a capping inversion
could become severe and have a large hail and wind-damage threat.
The threat could persist from late afternoon into the early evening.


....Central Appalachians/Mid-Atlantic...
A mid-level ridge will move eastward into the central Appalachians
today, as northwesterly flow remains to the east of the Appalachian
crest. At the surface, a moist airmass will be in place along much
of the southern and central Atlantic Seaboard. Surface dewpoints in
the 60s F will likely result in moderate instability by afternoon.
Although large-scale ascent will be weak, topographic forcing and
increasing low-level convergence could aid convective initiation as
surface temperatures warm up. Short-term model solutions suggest the
greatest convective potential will be across eastern Virginia, where
low-level flow is forecast to increase during the day. This,
combined with moderate deep-layer shear and steep low-level lapse
rates, may be enough for an isolated severe threat. Severe wind
gusts and large hail will be possible with supercells or short
intense line segments.

..Broyles/Lyons.. 05/15/2025

$$

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ACUS01 KWNS 151253
SWODY1
SPC AC 151252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Thu May 15 2025

Valid 151300Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
EAST-CENTRAL MINNESOTA...MUCH OF WISCONSIN...SOUTHERN AND WESTERN
LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST
OHIO...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
VIRGINIA AND NORTHEAST NORTH CAROLINA...

...SUMMARY...
Severe thunderstorms are expected across parts of the upper
Mississippi River Valley and Great Lakes this afternoon and evening.
Tornadoes, some of which could be strong, and very large hail and
damaging winds will be possible. Severe thunderstorms are also
expected through the lower Ohio River Valley, Ozarks and in parts of
the Mid-Atlantic.

...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley...
A deepening surface low will gradually consolidate as it moves north
across the eastern Dakotas today, and a warm front will lift north
through the OH Valley and into WI/Lower MI late this afternoon. As
strong large-scale ascent develops in association with a northeast-moving/negatively-tilted upper trough and left exit region
of a 300-mb jet streak, rapid thunderstorm development, or
re-intensification of ongoing storms, is expected from near the
surface low east/southeast along an arcing occluded/cold front over
central MN/western WI/northeast IL. A broken line of semi-discrete
cells is anticipated within a strongly unstable and amply-sheared
environment supporting supercell storm structures. Large hail,
possibly very large and in excess of 2.5 inches in diameter, will be
possible in addition to damaging wind gusts. Low-level shear will
support the potential for tornadoes with mature supercells, and the
risk for strong tornadoes will exist, especially towards evening as
low-level shear increases. Storms should tend to merge into clusters
or line segments with time, especially across southern lower
MI/northern IN/OH, where significant severe wind potential will
exist with an eastward moving complex of storms. The 30% wind/sig
severe wind area was extended east into southeast lower MI based on
latest hi-res guidance.

...Ozarks...
Thunderstorms have developed along the Red River in southeast
OK/western AR this morning, along the southern periphery of stronger
mid-level flow and with moderate elevated buoyancy. Although
larger-scale forcing remains nebulous, these storms may continue to
intensify and become surface based with time with the onset of
diurnal destabilization. Strong southwesterly flow will contribute
to ample deep-layer shear for supercells or a small cluster. Severe
hail and perhaps wind will be the primary severe hazards as storms
move across AR towards the mid-Mississippi Valley, and the Slight
(Level 2) Risk has been extended southwest across northern AR for
this potential.

...Central Appalachians/Mid-Atlantic...
Scattered thunderstorms are expected to develop in response to
diurnal heating and across the higher terrain this afternoon, and
move southeast within an environment of moderate/locally strong
surface-based instability and 35-40 kts of northwesterly deep shear.
In this parameter space, supercell structures and clusters will be
possible and pose a risk for large hail and damaging winds. Trends
in the 00z HREF and early morning hi-res guidance were the basis for
extending the Slight (Level 2) Risk southeast across portions of
northeast NC.

..Bunting/Dean.. 05/15/2025

$$

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ACUS01 KWNS 151630
SWODY1
SPC AC 151628

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Thu May 15 2025

Valid 151630Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
EAST-CENTRAL MINNESOTA...MUCH OF WISCONSIN...SOUTHERN AND WESTERN
LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST
OHIO...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
VIRGINIA AND NORTHEAST NORTH CAROLINA...

...SUMMARY...
Severe thunderstorms are expected across parts of the upper
Mississippi River Valley and Great Lakes this afternoon and evening.
Tornadoes, some of which could be strong, and very large hail and
damaging winds will be possible. Severe thunderstorms are also
expected through the lower Ohio River Valley, Ozarks and in parts of
the Mid-Atlantic.

...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley...
Recent satellite imagery shows an upper low over SD, with a
negatively tilted shortwave trough moving into the Mid MO Valley.
Surface analysis places an occluded surface low associated with this
system over southeast ND, with an occluded front extending
southeastward to a triple point over far southeast SD. A cold front
extends south-southeastward from this front across far western IA
and into far northeast MO before arcing more southwestward across
far western MO and more southwestward across western OK. A warm
front extends easterward from this triple point across southern MN
and then more southeastward across southwest WI and northern IL.
These boundaries, including the occluded front, will all act in
tandem with increasing large-scale forcing for ascent to force
thunderstorm development this afternoon and evening.

The ongoing storms from eastern SD into central MN are confirmation
of the buoyancy sampled in the 12Z MPX sounding. Expectation is for
instability to build across the region as heating and low-level
moisture advection occur amid steep mid-level lapse rates. Airmass destabilization and thunderstorm development is anticipated first
from the eastern Dakotas into MN, the occluded front as it shifts
northward as both the primary surface low and triple point low shift northwestward. Additional development is then anticipated farther
southeast along the warm front across WI. Storms that develop in the
vicinity of the occluded front will likely have elevated structures,
with large hail as the primary risk. Some isolated very large hail
(i.e. greater than 2" in diameter) is possible. Farther southeast,
the corridor along the warm front appears very favorable for
supercells capable of all severe hazards, including very large hail,
strong wind gusts, and tornadoes. A locally higher tornado potential
may exist from central into southeastern WI from 18Z-22Z. Deeper
mixing is anticipated farther south into northern IL, but the
overall environment will still support robust, organized updrafts.
There may be some trend initially for these storms to quickly become
outflow dominant, but strengthening mid-level flow across the region
after 21Z should aid in maintaining a more organized mode. Upscale
growth into a organized MCS appears probable after 00Z, with the
potential for significant-severe gusts as this line moves eastward
in southern Lower MI. The threat for damaging gusts and isolated
hail will persist throughout the night across Lower MI and the
middle/upper OH Valley.

...Ozarks into the TN Valley...
Additional thunderstorm development is anticipated this afternoon
across AR as a cold front pushes eastward across the region.
Moderate to strong flow aloft should allow for storms to move off
this boundary quickly into a strongly buoyant airmass downstream.
Warm air aloft could limit overall storm longevity during the
afternoon/early evening, but the warm/dry mid-levels are conducive
for producing strong outflows capable of damaging gusts. Whether or
not organization will occur along these outflows is uncertain, but a conditional risk for continued damaging gusts exists into TN.

Additional thunderstorms are possible during the evening and
overnight in the wake of the front. Persistent steep mid-level lapse
rates and strong shear will support large hail with some of these
storms.

...Central Appalachians/Mid-Atlantic...
Large-scale height rises are expected across the region, but
diurnal heating and orographic effects will aid in thunderstorm
development across the higher terrain this afternoon. Northwesterly
flow aloft will favor a southeastward storm motion within an
environment of moderate/locally strong instability. 35-45 kts of
northwesterly deep shear is anticipated, supporting supercell
structures and clusters, posing a risk for large hail and damaging
winds. The overall hodograph structure and resulting storm motion
appears favorable for some very large hail over 2" in diameter as
well.

..Mosier.. 05/15/2025

$$

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ACUS01 KWNS 151929
SWODY1
SPC AC 151927

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0227 PM CDT Thu May 15 2025

Valid 152000Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
EAST-CENTRAL MINNESOTA....MUCH OF WISCONSIN...SOUTHERN AND WESTERN
LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST
OHIO...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF
VIRGINIA AND NORTHEAST NORTH CAROLINA...

...SUMMARY...
Severe thunderstorms are expected across parts of the upper
Mississippi River Valley and Great Lakes this afternoon and evening.
Tornadoes, some of which could be strong, and very large hail and
damaging winds will be possible. Severe thunderstorms are also
expected through the lower Ohio River Valley, Ozarks and in parts of
the Mid-Atlantic.

...20z Update...
Only minor changes were made to trim probabilities behind ongoing
convective activity with this update.

The Enhanced Risk across the Midwest remains unchanged. Thunderstorm
activity has been ongoing in this region, with reports of a couple
of tornadoes in western Minnesota. Expect thunderstorm activity to
continue to strengthen in this area. See MCD#791 for more
information on the short term threats.

See previous discussion for more information concerning the broader
Slight Risk across the Mid to upper Mississippi Valley and in the
Central Appalachians and Mid-Atlantic below.

..Thornton/Mosier.. 05/15/2025

.PREV DISCUSSION... /ISSUED 1128 AM CDT Thu May 15 2025/

...Mid to Upper Mississippi Valley/Great Lakes/Ohio Valley...
Recent satellite imagery shows an upper low over SD, with a
negatively tilted shortwave trough moving into the Mid MO Valley.
Surface analysis places an occluded surface low associated with this
system over southeast ND, with an occluded front extending
southeastward to a triple point over far southeast SD. A cold front
extends south-southeastward from this front across far western IA
and into far northeast MO before arcing more southwestward across
far western MO and more southwestward across western OK. A warm
front extends easterward from this triple point across southern MN
and then more southeastward across southwest WI and northern IL.
These boundaries, including the occluded front, will all act in
tandem with increasing large-scale forcing for ascent to force
thunderstorm development this afternoon and evening.

The ongoing storms from eastern SD into central MN are confirmation
of the buoyancy sampled in the 12Z MPX sounding. Expectation is for
instability to build across the region as heating and low-level
moisture advection occur amid steep mid-level lapse rates. Airmass destabilization and thunderstorm development is anticipated first
from the eastern Dakotas into MN, the occluded front as it shifts
northward as both the primary surface low and triple point low shift northwestward. Additional development is then anticipated farther
southeast along the warm front across WI. Storms that develop in the
vicinity of the occluded front will likely have elevated structures,
with large hail as the primary risk. Some isolated very large hail
(i.e. greater than 2" in diameter) is possible. Farther southeast,
the corridor along the warm front appears very favorable for
supercells capable of all severe hazards, including very large hail,
strong wind gusts, and tornadoes. A locally higher tornado potential
may exist from central into southeastern WI from 18Z-22Z. Deeper
mixing is anticipated farther south into northern IL, but the
overall environment will still support robust, organized updrafts.
There may be some trend initially for these storms to quickly become
outflow dominant, but strengthening mid-level flow across the region
after 21Z should aid in maintaining a more organized mode. Upscale
growth into a organized MCS appears probable after 00Z, with the
potential for significant-severe gusts as this line moves eastward
in southern Lower MI. The threat for damaging gusts and isolated
hail will persist throughout the night across Lower MI and the
middle/upper OH Valley.

...Ozarks into the TN Valley...
Additional thunderstorm development is anticipated this afternoon
across AR as a cold front pushes eastward across the region.
Moderate to strong flow aloft should allow for storms to move off
this boundary quickly into a strongly buoyant airmass downstream.
Warm air aloft could limit overall storm longevity during the
afternoon/early evening, but the warm/dry mid-levels are conducive
for producing strong outflows capable of damaging gusts. Whether or
not organization will occur along these outflows is uncertain, but a conditional risk for continued damaging gusts exists into TN.

Additional thunderstorms are possible during the evening and
overnight in the wake of the front. Persistent steep mid-level lapse
rates and strong shear will support large hail with some of these
storms.

...Central Appalachians/Mid-Atlantic...
Large-scale height rises are expected across the region, but
diurnal heating and orographic effects will aid in thunderstorm
development across the higher terrain this afternoon. Northwesterly
flow aloft will favor a southeastward storm motion within an
environment of moderate/locally strong instability. 35-45 kts of
northwesterly deep shear is anticipated, supporting supercell
structures and clusters, posing a risk for large hail and damaging
winds. The overall hodograph structure and resulting storm motion
appears favorable for some very large hail over 2" in diameter as
well.

$$

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ACUS01 KWNS 160102
SWODY1
SPC AC 160100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Thu May 15 2025

Valid 160100Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE GREAT LAKES AND NORTHERN OHIO VALLEY...

...SUMMARY...
Severe thunderstorms are expected across parts of the upper
Mississippi River Valley and Great Lakes this evening. Tornadoes,
some of which could be strong, very large hail and damaging winds
will be possible. Severe thunderstorms are also expected later this
evening into tonight from the the lower Ohio Valley into the Ozarks.

...Upper Mississippi Valley/Great Lakes/Ohio Valley...
The latest water vapor imagery shows a mid-level low over the
eastern Dakotas, with a diffluent pattern over the upper Mississippi
Valley and western Great Lakes. A 500 mb jet is analyzed from the
Ozarks into western Illinois. At the surface, a front extends
southward from southern Wisconsin into central Illinois. To the east
of the boundary, surface dewpoints are in the 60s F. MLCAPE is
estimated to be from near 2000 J/kg in far southeast Wisconsin to
about 4000 J/kg in western Indiana. Ahead of the instability axis, a
line of severe storms is moving across Lake Michigan. Further south,
storms are developing along the western edge of the stronger
instability from south of Chicago southward into east-central
Illinois. The current thinking is that the convection over Lake
Michigan will move across the remainder of Lake Michigan, and remain
severe as it moves eastward into western Lower Michigan. Wind damage
will be likely along the leading edge of this convective line, with
gusts above 75 mph possible. A few tornadoes may develop with
rotating cells embedded in the line. Large hail will also be likely
with the more intense embedded supercells.

The storms in northeastern and east-central Illinois are expected to
move into western Indiana this evening, where strong instability,
and 0-6 km shear near 50 knots will be favorable for severe storms.
Mesoscale analysis currently has Significant Tornado Parameter
ranging from 3 to 5 over much of central and northern Indiana. As
low-level shear continues to increase over the next couple of hours,
a tornado threat may develop with supercells that remain
semi-discrete. The more intense supercells will also have a threat
for very large hail, potentially greater than 2 inches in diameter.
Wind damage will also be likely along the leading edge of a line
that is expected to become more organized later this evening.

Further south into southern Illinois and southern Indiana,
large-scale ascent will be limited. However, moderate instability is
present and low-level flow will strengthen this evening. This could
support isolated to scattered severe storms late this evening with
large hail and wind damage as the primary threats.

...Ark-La-Tex/Western Tennessee Valley...
A mid-level jet, analyzed by the RAP, will overspread the Ark-La-Tex
from late this evening into the overnight period. The jet is located
above a moist airmass that extends southeastward from the Ozarks
into the Gulf Coast States. Across this airmass, the RAP has MLCAPE
in the 2000 to 3500 J/kg range, with moderate deep-layer shear in
place. As large-scale ascent associated with the exit region of a
mid-level jet increases, scattered convective development will
become likely. The greatest potential for storms will be from
northeastern Arkansas eastward into Kentucky, along the northern
edge of the stronger instability. Large hail and wind damage will be
possible with the stronger cells, mainly after midnight through late
in the period.

..Broyles.. 05/16/2025

$$

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ACUS01 KWNS 160600
SWODY1
SPC AC 160558

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Fri May 16 2025

Valid 161200Z - 171200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF KENTUCKY...NORTHERN AND WESTERN TENNESSEE...SOUTHEAST MISSOURI...FAR
SOUTHERN ILLINOIS...SOUTHERN INDIANA...FAR SOUTHWEST OHIO...

...SUMMARY...
A regional outbreak of severe thunderstorms is likely this afternoon
into tonight across parts of the mid Mississippi, Ohio and Tennessee
Valleys. This will include intense supercells associated with
tornadoes, large hail and wind damage. Several strong tornadoes are
expected, and a long-track high-end tornado will be possible. From
the evening into the overnight, a bowing line segment is expected to
form with potential for tornadoes and damaging winds, some possibly
greater than 75 mph.

...Mid Mississippi and Ohio Valley/Tennessee Valley...
A negatively-tilted mid-level trough will move through the Upper
Midwest and mid Mississippi Valley today, as an associated 75 to 90
knot mid-level jet translates northeastward into the Ozarks. At the
surface, a low will move into the western Great Lakes, as a cold
front advances eastward into the mid Mississippi Valley. A very
moist airmass will remain in place ahead of the front, extending
eastward into the Ohio and Tennessee Valleys. Across this airmass,
surface dewpoints will be in the upper 60s and lower 70s F. Warming
surface temperatures will result in moderate to strong
destabilization across much of the moist sector by afternoon. An
area of low-level convergence is expected to become increasingly
focused from the Ozarks into the mid Mississippi Valley. This will
result in the initiation of scattered strong to severe storms around
midday. Several convective clusters are expected to organize and
move eastward into the lower Ohio Valley during the afternoon. Storm
coverage will expand markedly during the late afternoon and early
evening as low-level flow increases across the region.

Concerning the thermodynamic environment, a pristine airmass is
expected to be in place by afternoon. Model forecasts are in good
agreement that MLCAPE will peak from 3000 to 4000 J/kg from parts of
the Ozarks eastward into the Ohio and Tennessee Valleys. As
instability increases, deep-layer shear and lift are also expected
to increase as a mid-level jet approaches from the west. Ahead of
this feature, an 850 mb jet is forecast to develop over the mid
Mississippi Valley. This jet will gradually increase in strength
into the 45 to 65 knot range, moving eastward into western Kentucky
by late afternoon. Near the axis of the low-level jet at Paducah,
RAP forecast soundings at 23Z have MLCAPE near 3500 J/kg, 0-6 km
shear around 60 knots, and low to mid-level lapse rates near 7 C/km.
0-3 km helicity is forecast to be between 225 and 250 m2/s2. This
environment will support supercells and tornadoes. Several strong
tornadoes appear likely, and a high-end long-track tornado will be
possible from far southeast Missouri, into southern Illinois and
southern Indiana, southward into western Kentucky and far northern
Tennessee.

During the late afternoon, storm coverage is expected to become
widespread across the moist sector. Several supercell clusters will
move eastward from the mid Mississippi Valley into the Ohio and
Tennessee Valleys. Steep mid-level lapse rates will promote large
hail development. The more intense cores may have hailstones between
2 and 4 inches in diameter. Supercells will also be capable of
producing damaging wind gusts. During the early evening, the
wind-damage threat is expected to increase as some of the convective
clusters gradually transition into more linear structures. Winds
could exceed 75 mph along the leading edge of these faster-moving
bowing line segments. During the evening, multiple bow echos are
expected to form that will result in extensive wind damage swaths.
Wind damage is expected across a broad area, including parts of the
mid Mississippi, Ohio and Tennessee Valleys into the central
Appalachian mountains.

...Ark-La-Tex/Lower Mississippi Valley...
A very moist airmass will be in place today across the Ark-La-Tex
and lower Mississippi Valley. Surface dewpoints in the lower to mid
70s F will result in moderate to strong destabilization across much
of this airmass. A capping inversion is expected to be in place for
much of the day, but should weaken late in the afternoon as a
mid-level jet moves eastward into the mid Mississippi Valley. The
southern edge of the jet will help to increase large-scale ascent,
aiding convective development. In response, a few clusters of storms
will form and move eastward into the lower Mississippi Valley during
the late afternoon and early evening. In areas that strongly
destabilize, storms could be capable of producing large hail and
wind damage. Hailstones greater than 2 inches in diameter will be
possible with intense supercell cores.

..Broyles/Weinman.. 05/16/2025

$$

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ACUS01 KWNS 161247
SWODY1
SPC AC 161246

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0746 AM CDT Fri May 16 2025

Valid 161300Z - 171200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EAST-CENTRAL AND SOUTHEAST MISSOURI...WESTERN AND CENTRAL
KENTUCKY...SOUTHERN ILLINOIS AND INDIANA...SOUTHWEST
OHIO...NORTHWEST TENNESSEE...AND NORTHEAST ARKANSAS...

...SUMMARY...
A regional outbreak of severe thunderstorms is likely this afternoon
into tonight across parts of the mid Mississippi, Ohio and Tennessee
Valleys. This will include intense supercells associated with
tornadoes, large hail and wind damage. Several strong tornadoes are
expected, and a long-track high-end tornado will be possible. From
the evening into the overnight, a bowing line segment is expected to
form with potential for tornadoes and damaging winds, some possibly
greater than 75 mph.

...Mid Mississippi and Ohio Valley/Tennessee Valley Region...
As an upper-level low near the MN/ND border shifts east today, a
mid-level jet streak will move from the Plains into the
mid-Mississippi Valley. A surface cold front will move east across
the Great Lakes, Midwest and OH/TN Valley region this afternoon and
tonight. An expansive warm/moist sector will destabilize during the
day, setting the stage for a regional severe weather outbreak this
afternoon and tonight.

Scattered severe thunderstorms, with a history of large hail, were
ongoing at 13z from northeast AR into eastern KY. Clusters of severe
storms, including supercells, will continue moving northeast within
this corridor through at least early afternoon. The eventual
longevity of these storms remains uncertain, however downstream
diurnal destabilization could allow storms with a severe hail/wind
threat to move into WV/western VA this afternoon.

In the wake of these morning storms, destabilization will occur as a
warm front lifts north, with strong instability (MLCAPE in excess of
2500 J/kg) developing from portions of eastern MO east into the
OH/TN Valley region, and south in advance of the front into eastern
TX. The presence of strong mid-level flow will contribute to
deep-layer shear averaging 50 kts or higher across a large area.

Vigorous redevelopment of severe storms is expected by early
afternoon across southern/eastern MO as height falls overspread the
area. More isolated development is expected southward along the cold
front towards 00Z. Initial storm development will strongly favor
supercell storm mode with all severe hazards possible, including the
potential for strong tornadoes across the Moderate/Enhanced Risk
areas where low-level shear will be strongest. Large to very large
hail will also be possible with mature supercells this afternoon
through early evening. As storms continue moving east across the
OH/TN Valley region, eventual upscale growth into multiple bowing
segments is expected. The tornado threat will continue, especially
with QLCS circulations, and significant severe gusts will also be
possible.

...Ark-La-Tex/Lower Mississippi Valley...
Warm mid-level temperatures will tend to delay thunderstorm
initiation along the southward-trailing cold front into northeast TX
until later in the day, however at least isolated development is
expected towards 22z-00z. MLCAPE in excess of 3000 J/kg and 45-55
kts of deep-layer shear oriented favorably relative to the front
suggests a supercell mode with large to very large hail, along with
damaging gusts. Although weaker low-level shear will be present in
this area, some potential for a tornado will exist with any mature
supercell. With time, storms may increase in coverage and begin to
cluster in an environment favorable for a continued severe wind/hail
threat.

...Portions of the Mid-Atlantic/northern DelMarVa Peninsula...
As the southern portion of the long-lived MCS over PA/NY continues
moving east/southeast today, the potential will exist for
re-development of organized storms, including supercells, over
portions of southeast PA/southern NJ and the northern DelMarVa
peninsula. With moderate west/northwest flow in place to the east of
the upper level ridge, RAP/HRRR forecast soundings depict sufficient
deep shear and moderate instability for a severe hail and wind risk.
Some consideration was given for higher severe probabilities in this
area, however uncertainty remains on the location of a corridor of
greater risk.

..Bunting/Marsh.. 05/16/2025

$$

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ACUS01 KWNS 161629
SWODY1
SPC AC 161628

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Fri May 16 2025

Valid 161630Z - 171200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING MIDDLE MISSISSIPPI AND LOWER OHIO VALLEYS...

...SUMMARY...
A regional outbreak of severe thunderstorms is likely this afternoon
into tonight across parts of the mid Mississippi, Ohio and Tennessee
Valleys. This will include intense supercells with strong,
potentially long-track tornadoes and very large hail. The threat for
damaging winds in excess of 75 mph will increase into this evening
as storms grow into larger clusters.

...Mid MS Valley to the Mid-Atlantic through tonight...
An occluded 984 mb cyclone will move slowly eastward toward the
upper Great Lakes and fill through tonight, as a trailing cold front
progresses across MO/IL/IN/MI. Ongoing thunderstorm clusters will
likely persist through the afternoon along the primary
moisture/buoyancy gradient into the northern Mid-Atlantic, and with
a developing cold pool from TN/KY into VA/NC within the warm sector.
MLCAPE increasing to 2000 J/kg or greater, steepening low-level
lapse rates, and sufficient deep-layer vertical shear (effective
bulk shear of 40-50 kt) will maintain a mix of embedded supercells
and bowing segments capable of producing very large hail (2 inch
diameter or larger), thunderstorm gusts of 60-75 mph, and a couple
of tornadoes.

Farther west and in the wake of the ongoing TN/KY storms, rapid
recovery is underway across southern MO where moisture advection and
strong surface heating will result in rapid destabilization.
Visible imagery shows evidence of ascent over northwest AR/southwest
MO that will soon interact with the destabilizing warm sector.
Supercell development is expected by midday into early afternoon
from south central into east central MO, and storms will
subsequently expand in coverage while spreading quickly
east-northeastward across southern/central IL this afternoon and
into IN late this afternoon/evening. The initial storms in MO will
likely remain semi-discrete with the potential to producing very
large hail (in excess of 3 inches in diameter) and a couple of
strong tornadoes given very long hodograph with sufficient low-level
shear. Gradual upscale growth into clusters/line segments is
expected through storm interactions, with an increase in the
potential for swaths of 65-85 mph gusts into this evening. More
isolated supercell development may also occur later this afternoon
along the modifying outflow boundary into KY, where all hazards are
expected.

...Northern IL into Lower MI this afternoon/evening...
An embedded speed max and associated zone of ascent now over
northern MO will eject quickly east-northeastward toward Lower MI by
early tonight. The degree of moistening/destabilization will be
modulated by how quickly storms form and how widespread coverage is
this afternoon farther to the south from IL into IN.

...AR into southeast OK and northeast/central TX this afternoon...
Despite some cloud cover, surface heating in cloud breaks is
allowing surface temperatures to warm into the 80s with low-mid 70s boundary-layer dewpoints, beneath midlevel lapse rates in excess of
8 C/km. Scattered thunderstorm development is expected this
afternoon along the primary wind shift from AR/southeast OK into
northeast and potentially central TX. MLCAPE of 3000-4000 J/kg and
long hodographs with strong deep-layer shear will favor supercells
capable of producing very large hail (3-4 inches in diameter) with
the initial discrete storms, and damaging gusts of 60-75 mph. The
tornado threat is less certain given relatively weak low-level shear
(as a result of the primary mass response/low-level jet into the
TN/OH Valleys), and will likely rely on favorable storm
interactions.

..Thompson/Grams.. 05/16/2025

$$

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ACUS01 KWNS 161932
SWODY1
SPC AC 161931

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 PM CDT Fri May 16 2025

Valid 162000Z - 171200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS THE
MIDDLE MISSISSIPPI AND LOWER OHIO VALLEYS...

...SUMMARY...
A regional outbreak of severe thunderstorms is likely this afternoon
into tonight across parts of the mid Mississippi, Ohio and Tennessee
Valleys. This will include intense supercells with strong,
potentially long-track tornadoes and very large hail. The threat for
damaging winds in excess of 75 mph will increase into this evening
as storms grow into larger clusters.

...20z Update...
No changes are needed to the current D1 Convective Outlook.

Supercells are ongoing across Missouri producing large hail (up to
3-4 in). These storms will continue eastward through time across the
Moderate Risk. The area ahead of these storms is continuing to warm
and destabilize rapidly, with some increase in low level shear
expected through the evening with an increase in the low level jet.
This will support increasing potential for tornadoes, a couple of
which may be intense and long-track across eastern Missouri into
southern Illinois, southern Indiana, and western Kentucky. See
MCD#817 for more information on the short term risk.

Elsewhere, a cluster of storms continue across portions of the
eastern US from West Virginia to eastern Kentucky which will slowly
move into Virginia and North Carolina. See MCD#816 for more
information on the short term risk.

For more information on the potential risk across southeast Oklahoma
into Texas this afternoon/evening, see previous discussion below.

..Thornton/Mosier.. 05/16/2025

.PREV DISCUSSION... /ISSUED 1128 AM CDT Fri May 16 2025/

...Mid MS Valley to the Mid-Atlantic through tonight...
An occluded 984 mb cyclone will move slowly eastward toward the
upper Great Lakes and fill through tonight, as a trailing cold front
progresses across MO/IL/IN/MI. Ongoing thunderstorm clusters will
likely persist through the afternoon along the primary
moisture/buoyancy gradient into the northern Mid-Atlantic, and with
a developing cold pool from TN/KY into VA/NC within the warm sector.
MLCAPE increasing to 2000 J/kg or greater, steepening low-level
lapse rates, and sufficient deep-layer vertical shear (effective
bulk shear of 40-50 kt) will maintain a mix of embedded supercells
and bowing segments capable of producing very large hail (2 inch
diameter or larger), thunderstorm gusts of 60-75 mph, and a couple
of tornadoes.

Farther west and in the wake of the ongoing TN/KY storms, rapid
recovery is underway across southern MO where moisture advection and
strong surface heating will result in rapid destabilization.
Visible imagery shows evidence of ascent over northwest AR/southwest
MO that will soon interact with the destabilizing warm sector.
Supercell development is expected by midday into early afternoon
from south central into east central MO, and storms will
subsequently expand in coverage while spreading quickly
east-northeastward across southern/central IL this afternoon and
into IN late this afternoon/evening. The initial storms in MO will
likely remain semi-discrete with the potential to producing very
large hail (in excess of 3 inches in diameter) and a couple of
strong tornadoes given very long hodograph with sufficient low-level
shear. Gradual upscale growth into clusters/line segments is
expected through storm interactions, with an increase in the
potential for swaths of 65-85 mph gusts into this evening. More
isolated supercell development may also occur later this afternoon
along the modifying outflow boundary into KY, where all hazards are
expected.

...Northern IL into Lower MI this afternoon/evening...
An embedded speed max and associated zone of ascent now over
northern MO will eject quickly east-northeastward toward Lower MI by
early tonight. The degree of moistening/destabilization will be
modulated by how quickly storms form and how widespread coverage is
this afternoon farther to the south from IL into IN.

...AR into southeast OK and northeast/central TX this afternoon...
Despite some cloud cover, surface heating in cloud breaks is
allowing surface temperatures to warm into the 80s with low-mid 70s boundary-layer dewpoints, beneath midlevel lapse rates in excess of
8 C/km. Scattered thunderstorm development is expected this
afternoon along the primary wind shift from AR/southeast OK into
northeast and potentially central TX. MLCAPE of 3000-4000 J/kg and
long hodographs with strong deep-layer shear will favor supercells
capable of producing very large hail (3-4 inches in diameter) with
the initial discrete storms, and damaging gusts of 60-75 mph. The
tornado threat is less certain given relatively weak low-level shear
(as a result of the primary mass response/low-level jet into the
TN/OH Valleys), and will likely rely on favorable storm
interactions.

$$

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ACUS01 KWNS 170048
SWODY1
SPC AC 170047

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0747 PM CDT Fri May 16 2025

Valid 170100Z - 171200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM EXTREME
NORTHEAST ARKANSAS INTO CENTRAL KENTUCKY...

...SUMMARY...
A regional outbreak of severe thunderstorms will continue tonight
across parts of the mid Mississippi, Ohio and Tennessee Valleys.
This will include intense supercells with strong, potentially
long-track tornadoes and very large hail. The threat for damaging
winds in excess of 75 mph will increase this evening as storms grow
into larger clusters.

...01z Update...

Seasonally deep cyclone is shifting east across the upper MS Valley
toward the upper Great Lakes region. Early-evening satellite imagery
supports this with the center of the upper low currently over
northern MN. Multiple short-wave troughs are rotating into/through
the base of the trough, but the primary zone of noteworthy ascent is
currently aiding an elongated corridor of deep convection from
central Indiana, southwest across northern Arkansas into central TX,
where only the southern influence of this upper trough is evident.

Multiple long-lived supercells have evolved along this corridor,
especially from southern Indiana into northeast Arkansas. This zone
is strongly sheared, strongly buoyant, and adequately forced for the continuation of severe supercells. Environmental conditions remain
favorable for intense updrafts, along with the potential for
long-track tornadoes. Very large hail and severe winds are also
likely with this activity. Through late evening, the primary
corridor for the most concentrated severe will extend from northeast
Arkansas into central Kentucky. Later tonight, some potential for
upscale growth may yield a forward propagating MCS. This activity
will move toward the central/southern Appalachians with an attendant
severe risk, including all severe hazards.

..Darrow.. 05/17/2025

$$

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ACUS01 KWNS 170545
SWODY1
SPC AC 170544

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1244 AM CDT Sat May 17 2025

Valid 171200Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
NORTH TEXAS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
SOUTHERN PLAINS AND OVER PORTIONS OF THE NORTHEAST...

...SUMMARY...
Severe thunderstorms producing large to very large hail, damaging
gusts and a couple of tornadoes are expected across the southern
Plains. Additional severe storms are possible across the Northeast.

...Southern Plains Region...

Strong southern-stream short-wave trough is clearly evident in
water-vapor imagery just west of the Baja Peninsula early this
morning. This feature appears to be handled well by latest model
guidance, and is forecast to advance into southern AZ/northwest
Mexico by sunrise, and to near the NM/TX border by 18/00z. There is
some indication that a weak disturbance will translate into far west
TX just ahead of the main trough, and this weak feature may prove to
be the more meaningful disturbance in regards to severe thunderstorm development later today...especially across north TX.

Latest surface analysis depicts a sharp demarcation in moisture
along a stalled surface front across TX. Surface dew points in the
lower 70s will easily advance north with this boundary as it returns
across the southern Plains today. Extreme buoyancy will develop
across the warm sector ahead of the aforementioned disturbance, and
more pronounced short wave. 00z model guidance is fairly consistent
regarding early-day convective initiation along the dry line.
Forecast soundings suggest negligible CINH from SJT-ABI by 17-18z,
and robust convection will likely develop by early afternoon.
Deep-layer flow is more than sufficient for supercells and cool,
steep lapse rates favor very large hail (>3 inches possible) with
the strongest storms. Given the strong, consistent signal in the 00z
model guidance, will increase severe probabilities across much of
north TX to account for scattered-numerous supercells/clusters
spreading toward the DFW Metroplex by late afternoon. While
low-level shear is not particularly strong, some tornado potential
will likely exist with the more organized supercells.

Farther north across OK into southern KS, substantial
destabilization is expected as 70s dew points spread rapidly north
as a warm front establishes itself across southern KS overnight.
Precip signal is not particularly noteworthy along the dry line over
OK, but weak CINH does cause concern for isolated supercell
development. Storm potential appears somewhat greater across
southern KS near/after sunset as moisture returns to this region.
Some consideration was given to higher tornado probabilities along a
narrow wedge of northwest OK into southwest KS near the boundary for
this possibility. This may need to be adjusted in later outlooks.


...Northeast...

Strong 12hr mid-level height falls will spread across much of the
northeastern U.S. today in response to the approaching Great Lakes
upper low. High-level diffluent flow aloft will overspread much of
NY into New England as the left-exit region of the 500mb jet
translates across PA. Scattered thunderstorms are expected to
develop along/ahead of the synoptic cold front across upstate NY,
with subsequent movement expected into western New England.
Wind/hail are the primary risks with this activity, though a brief
tornado can not be ruled out with stronger supercells.

..Darrow/Halbert.. 05/17/2025

$$

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ACUS01 KWNS 171249
SWODY1
SPC AC 171248

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0748 AM CDT Sat May 17 2025

Valid 171300Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTH
TEXAS AND SOUTHERN OKLAHOMA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
UPSTATE NEW YORK AND WESTERN NEW ENGLAND...

...SUMMARY...
Severe thunderstorms producing large to very large hail, damaging
gusts and a couple of tornadoes are expected across the southern
Plains. Additional severe storms are possible across the Northeast.

...Southern Plains Region...
Water vapor imagery depicts a pronounced southern stream upper-level
trough over the Baja Peninsula this morning, with evidence of a lead
impulse approaching southwest TX. This leading impulse will
contribute to ascent in the vicinity of a sharpening dryline across
Western North Texas/Oklahoma by early afternoon. To the east of the
dryline, extreme instability (MLCAPE in excess of 4000 J/kg) is
expected to develop given the moist low-level air mass and
relatively cool mid-level thermal profiles. With negligible CINH by
early/mid afternoon, thunderstorms are expected to develop along the
dryline and move east/northeast into North Texas and southern
Oklahoma. Supercells will be the dominant mode initially, with a
risk for very large hail (in excess of 3.5 inches), and damaging
gusts. Although low-level shear is not especially strong, some
tornado risk will exist given the magnitude of instability and
potential for storm-scale interactions. Eventual upscale growth into
a severe MCS is expected as storms continue to move across North
TX/southern OK this evening. Severe wind probabilities have been
increased across the Enhanced Risk area for the expectation of a
more concentrated corridor of damaging wind potential.

Across central/northwest OK, a narrowing plume of instability will
be present east of the dryline and south of an east-west oriented
frontal boundary. Within this moist sector, strong to extreme
instability and around 50 kts of deep-layer shear will support at
least isolated supercell storm development this afternoon over
central OK. Very large hail (3 inches or greater) will be possible,
in addition to damaging gusts. Tornado risk will be dependent on
storm interactions. Thunderstorm development over northwest OK is
more uncertain, however should a storm develop a supercell mode will
be favored with all hazards possible.

...Northeast...
Strong mid-level height falls will spread across much of the
northeastern U.S. today in response to the approaching Great Lakes
upper low. Large-scale ascent will increase with as the left-exit
region of the 500mb jet translates across PA. Scattered
thunderstorms, including supercells, are expected to develop
along/ahead of the synoptic cold front across upstate NY, with
subsequent movement expected into western New England. Multiple
rounds of thunderstorms are likely, with severe hail and winds as
the primary risks. A tornado or two cannot be ruled out with any
stronger and semi-discrete supercell. Please refer to Mesoscale
Discussion 836 for additional details on short-term expectations.

...Northern Utah Vicinity...
A Marginal Risk has been introduced across northern UT and vicinity
given expected higher concentration of storms within a deeply-mixed
boundary layer. Strong/severe gusts will be the primary severe risk.

...Lower Mississippi Valley/Southeast...
Thunderstorms continue from central MS into the western Carolinas at
13z, with occasional pulses of strong/severe cells. Isolated
stronger storms will remain possible as diurnal
heating/destabilization takes place in the presence of ample shear
for organized storms. However, with the line of convection oriented
generally parallel to the shear vector, any severe risk should be
isolated. Strong gusts will be the primary hazard.

..Bunting/Marsh.. 05/17/2025

$$

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ACUS01 KWNS 171618
SWODY1
SPC AC 171617

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1117 AM CDT Sat May 17 2025

Valid 171630Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
UPSTATE NEW YORK AND WESTERN NEW ENGLAND...

...SUMMARY...
Severe thunderstorms producing large to very large hail, damaging
gusts and a couple of tornadoes are expected across the southern
Plains. Additional severe storms are possible across the Northeast.

...Central TX/Southern OK into the ArkLaTex Region...
Morning water vapor loop shows a well-defined shortwave trough over
southern AZ tracking northeastward. Ahead of this system, southerly
low-level winds and steep lapse rates aloft have established a very
moist and extremely unstable air mass from southern OK into central
TX. Dewpoints in the low/mid 70s and ample daytime heating will
yield afternoon MLCAPE values over 4000 J/kg. As the upper system
and associated mid-level jet max approach the dryline, thunderstorms
are expected to rapidly develop by mid-afternoon. Splitting
supercells capable of very large hail will be the main initial
concern, along with damaging winds and a tornado or two. Most model
solutions suggest upscale growth of these storms into a bowing MCS
by evening, tracking eastward across the ArklaTex region. Have
extended the ENH a little farther east to accommodate this scenario,
with damaging winds and large hail being the main concerns. This
cluster of storms may persist overnight, tracking into
central/northern MS.

...Northwest OK...
The plume of dense cirrus ahead of the AZ shortwave trough will move
east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds
near a retreating warm front will provide a corridor of strong
instability and favorable low-level shear for supercell development.
The coverage of storms in this area is uncertain and varied between
the morning CAM solutions. However, the storms that form will pose
a risk of very large hail, damaging winds, and a tornado or two. It
is also unclear how far east this threat may persist, with some
concern for an MCS tracking into northeast OK overnight.

...NY/New England...
A progressive shortwave trough and associated mid-level jet is
tracking eastward across the Great Lakes region today. Cooling
temperatures aloft and strong daytime heating will lead to pockets
of moderate CAPE and steep low/mid level lapse rates. Storms are
beginning to form across NY and will move into a progressively more
favorable air mass for strong/severe convection (including a few
supercells) by mid-afternoon. Locally damaging winds are the main
concern, but the strongest cells could also produce hail and perhaps
a tornado or two. Refer to MCD #837 for further details.

..Hart/Moore.. 05/17/2025

$$

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ACUS01 KWNS 171956
SWODY1
SPC AC 171954

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0254 PM CDT Sat May 17 2025

Valid 172000Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA.......

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF
UPSTATE NEW YORK AND WESTERN NEW ENGLAND...

...SUMMARY...
Severe thunderstorms producing large to very large hail, damaging
gusts and a couple of tornadoes are expected across the southern
Plains. Additional severe storms are possible across the Northeast.

...20z Update...
Adjustments were made to the 20z to remove the Marginal risk across
portions of Georgia into South Carolina and across the northeast
behind morning convection.

The Slight Risk and Moderate Risk were nudged further south in far
southern Texas to account for potential for storms to come out of
Mexico this evening with potential for large hail and severe winds.


Otherwise, the risk areas across the main region of the
southern/central Plains were not changed. Thunderstorm development
has begun across the dryline from southern/central Texas to the Red
River in Oklahoma. See MCD#840 and MCD#838 for more information on
the short term risks in these areas.

..Thornton/Hart.. 05/17/2025

.PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/

...Central TX/Southern OK into the ArkLaTex Region...
Morning water vapor loop shows a well-defined shortwave trough over
southern AZ tracking northeastward. Ahead of this system, southerly
low-level winds and steep lapse rates aloft have established a very
moist and extremely unstable air mass from southern OK into central
TX. Dewpoints in the low/mid 70s and ample daytime heating will
yield afternoon MLCAPE values over 4000 J/kg. As the upper system
and associated mid-level jet max approach the dryline, thunderstorms
are expected to rapidly develop by mid-afternoon. Splitting
supercells capable of very large hail will be the main initial
concern, along with damaging winds and a tornado or two. Most model
solutions suggest upscale growth of these storms into a bowing MCS
by evening, tracking eastward across the ArklaTex region. Have
extended the ENH a little farther east to accommodate this scenario,
with damaging winds and large hail being the main concerns. This
cluster of storms may persist overnight, tracking into
central/northern MS.

...Northwest OK...
The plume of dense cirrus ahead of the AZ shortwave trough will move
east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds
near a retreating warm front will provide a corridor of strong
instability and favorable low-level shear for supercell development.
The coverage of storms in this area is uncertain and varied between
the morning CAM solutions. However, the storms that form will pose
a risk of very large hail, damaging winds, and a tornado or two. It
is also unclear how far east this threat may persist, with some
concern for an MCS tracking into northeast OK overnight.

...NY/New England...
A progressive shortwave trough and associated mid-level jet is
tracking eastward across the Great Lakes region today. Cooling
temperatures aloft and strong daytime heating will lead to pockets
of moderate CAPE and steep low/mid level lapse rates. Storms are
beginning to form across NY and will move into a progressively more
favorable air mass for strong/severe convection (including a few
supercells) by mid-afternoon. Locally damaging winds are the main
concern, but the strongest cells could also produce hail and perhaps
a tornado or two. Refer to MCD #837 for further details.

$$

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ACUS01 KWNS 180105
SWODY1
SPC AC 180103

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0803 PM CDT Sat May 17 2025

Valid 180100Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE SOUTHERN PLAINS INTO THE ARKLATEX REGION...

...SUMMARY...
Isolated severe thunderstorms producing large to very large hail,
damaging gusts and a couple of tornadoes remain possible across the
southern Plains into the Arklatex region.

...01z Update...

Early-evening water-vapor suggests a weak short-wave trough has
advanced into the high Plains, extending from southwest KS into the
eastern TX Panhandle. This feature is partly responsible for drawing
richer boundary-layer moisture into northwest OK. Latest surface
analysis suggests a well-defined warm front currently extends across south-central OK to near GAG in Ellis County. Low-level warm
advection is focused along/north of this wind shift, and some
nocturnal increase in 850mb flow could aid upscale growth to ongoing
convection over the northeast TX Panhandle. This activity should
propagate downstream within the warm-advection zone, primarily
across the northern half of OK.

Additional strong/severe thunderstorm clusters persist from
southeast OK into northeast TX. 00z sounding from SHV exhibits a
very buoyant air mass characterized by 0-6km bulk shear on the order
of 45kt. Organized convection should propagate in a general eastward
direction, along the warm advection corridor, across the Arklatex.
Hail/wind threat continues.

..Darrow.. 05/18/2025

$$

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ACUS01 KWNS 180542
SWODY1
SPC AC 180540

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Sun May 18 2025

Valid 181200Z - 191200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF KANSAS AND OKLAHOMA...

...SUMMARY...
Severe thunderstorms capable of all severe hazards are expected
later today across portions of the central and southern Plains. The
potential for a few strong tornadoes exists across parts of Kansas
and Oklahoma.

...Central/Southern Plains...

Strong upper trough is digging southeast across the Great Basin
early this morning. This feature is forecast to advance into the
Four Corners region by 18z as 500mb speed max translates across AZ
into NM. By early evening, strongest mid-level flow is forecast to
extend across northeast NM into western KS. This evolution will
suppress the height field across the central High Plains such that
large-scale forcing will likely influence the dry line as far south
as I-40 near the TX/OK border.

While several 00z models struggle to develop convection along the
dry line, strong boundary-layer heating is expected across the
southern High Plains. Zero-3km lapse rates will approach dry
adiabatic by late afternoon as surface temperatures soar through the
mid 90s across the eastern TX Panhandle into the TX South Plains. As
a result, deep thermals are expected and isolated thunderstorms
should develop as CINH will prove minimal.

Scattered convection is currently noted across northeast OK into
southeast KS/southwest MO. This activity will likely persist into
the early parts of the day1 period. Strongest low-level moisture
surge should be across western OK into extreme southwest KS as LLJ
will focus across this portion of the Plains early in the period.
While early-day convection may generate locally severe hail/wind,
the primary concern for severe will be with late-day convection.
Current thinking is strong heating along the dry line will prove
instrumental in thunderstorm development as convective temperatures
are breached, sometime after 22z. Primary corridor for initiation
should be across southwest KS into northwest OK. This activity will
be strongly sheared and supercells should mature quickly as they
move northeast toward/across the warm front draped downstream across
KS. Very large hail and tornadoes are certainly a concern with
surface-based convection, while hail is the primary concern with
elevated convection north of the warm front.

It's not entirely clear how much convection will develop along the
dry line south of I40, especially across TX. However, minimal
inhibition warrants concern, as any updrafts that evolve within a
strongly sheared and buoyant air mass should produce at least large
hail.

Farther north, left-exit region of mid-level jet will encourage a
secondary corridor of strong/severe thunderstorms from northeast CO
into western NE. Surface low is expected to track across eastern CO
into western KS which will maintain a moist/upslope component to
boundary layer across this portion of the High Plains. Strong
low-level warm advection will assist organized convection as it
spreads northeast during the overnight hours.

..Darrow/Halbert.. 05/18/2025

$$

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ACUS01 KWNS 181255
SWODY1
SPC AC 181253

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0753 AM CDT Sun May 18 2025

Valid 181300Z - 191200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR SOUTHWEST
AND CENTRAL KANSAS INTO FAR NORTHWEST OKLAHOMA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
LOWER MISSISSIPPI VALLEY AND PARTS OF ALABAMA AND GEORGIA...

...SUMMARY...
Severe thunderstorms capable of all severe hazards are expected
later today across portions of the central and southern Plains.
Several strong to intense tornadoes are possible.

...Central/Southern Plains...
Water-vapor imagery this morning shows a potent mid- to upper-level
trough over the Four Corners with a couple of downstream MCVs moving east-southeast over AR and AL this morning. A 500-mb speed max (60+
kt) is forecast to move through the base of this trough and eject
into the TX Panhandle/southwestern KS late this afternoon and
evening as the trough evolves into a negative tilt. Rich low-level
moisture was observed at both surface sites and raob sites over the
southern Great Plains this morning. Increasing moisture at 850 mb
was sampled beneath very steep 700-500 mb lapse rates on the Dodge
City raob.

Southerly low-level flow is forecast to increase today across the southern-central Great Plains as a composite frontal zone/outflow
over OK advances northward as a warm front into southern KS later
this afternoon. Models show surface dewpoints rising into the 60s
across western KS with lower 70s farther south near the OK/KS border
and locales southward along/east of the dryline later this
afternoon. Model guidance shows the strongest signal for scattered
storm development from parts of the central High Plains southeast
into southwest KS later this afternoon/evening as large-scale ascent overspreads the destabilizing moist/unstable sector.

Confidence is greatest in scattered supercells developing across western/southwest KS later this afternoon as CINH erodes amidst
strong boundary layer heating. A very to extremely unstable airmass
with long hodographs will rapidly promote supercell evolution with
any sustained/maturing updraft. The LLJ is forecast to intensify
during the late afternoon/evening and enlarge the hodographs,
supporting tornado potential. The combination of shear/buoyancy
will become very favorable for intense supercells capable of large
to giant hail (potentially 3-4+ inches in diameter) and strong to
intense tornadoes, especially from western OK northward into
south-central and western KS. It is within a focused corridor on
the northern periphery of the richer moisture over parts of
south-central and southwest KS where a potent environment and
expected higher storm coverage prompted an upgrade to Moderate Risk.
Lower storm coverage is expected farther south across western OK,
but a similar environment will exist.

Similar to previous forecast thinking, it remains uncertain how much
convection will develop along the dry line south of I40, especially
across TX. However, minimal inhibition warrants concern, as any
updrafts that evolve within a strongly sheared and buoyant air mass
should produce at least large hail.

Farther north, left-exit region of mid-level jet will encourage a
secondary corridor of strong/severe thunderstorms from northeast CO
into western NE. Surface low is expected to track across eastern CO
into western KS which will maintain a moist/upslope component to
boundary layer across this portion of the High Plains. Strong
low-level warm advection will assist organized convection as it
spreads northeast during the overnight hours.

...AR eastward into GA...
A pair of MCVs this morning are aiding in a couple of severe
thunderstorm clusters being sustained along a residual frontal zone
that serves as the northern periphery of richer low-level moisture.
Short-term model guidance has varied considerably in the depiction
of these MCS. Nonetheless, the 11 UTC BMX raob showed an very
unstable airmass (3300 J/kg MUCAPE) and 65-kt 500 mb flow. Current
thinking is both MCSs will pose a risk for mainly damaging gusts
through this morning.

..Smith/Marsh.. 05/18/2025

$$

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ACUS01 KWNS 181618
SWODY1
SPC AC 181616

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1116 AM CDT Sun May 18 2025

Valid 181630Z - 191200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR SOUTHWEST
AND CENTRAL KANSAS INTO FAR NORTHWEST OKLAHOMA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MISSISSIPPI...CENTRAL ALABAMA...AND SOUTHERN GEORGIA...

...SUMMARY...
Severe thunderstorms capable of all severe hazards are expected this
afternoon and evening across portions of the central and southern
Plains. Several strong to intense tornadoes are possible.

...KS/OK...
A large upper trough continues to deepen over the western US, with a
band of 60-70 knot southwesterly mid-level flow extending across NM
into western KS/OK. The surface dryline will mix eastward into
western KS and along the TX/OK border by mid-afternoon, with the air
mass to the east becoming extremely unstable with dewpoints in the
upper 60s and MLCAPE values over 4000 J/kg. Strong
southerly/southeasterly low-level winds throughout the warm sector
will provide a conditionally favorable environment for intense
supercells capable of very large hail, damaging winds, and
tornadoes. However, morning model guidance continues to show
diverse solutions regarding coverage of convection later today.

The area of greatest confidence in storm development and intensity
will be near the warm front/dryline triple point over south-central
KS. Discrete supercell development appears likely here, with
forecast soundings showing favorable hodograph structures to promote
a risk of strong tornadoes. The MDT risk has been extending
slightly eastward along the warm front. Farther south along the
dryline in western OK, confidence in initiation is lower. However,
any storm that can form will be capable of all hazards.

...Western North TX...
Another region of higher confidence in convective initiation will be
over western north TX along the dryline. Hot surface temperatures
in vicinity of a dryline bulge will aid in storm development. These
storms will likely expand eastward and into southwest OK through the
evening, with very large hail and damaging winds possible.

...MS/AL/GA...
A narrow corridor of SLGT risk has been added for this afternoon
from eastern MS across central AL and southern GA. Multiple MCSs
are ongoing in this corridor, with associated outflow boundaries
present. These boundaries may be the focus for further development
this afternoon, with sufficient CAPE/shear combinations to pose a
risk of damaging winds in the strongest cells.

..Hart/Moore.. 05/18/2025

$$

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ACUS01 KWNS 182007
SWODY1
SPC AC 182005

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0305 PM CDT Sun May 18 2025

Valid 182000Z - 191200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR SOUTHWEST
AND CENTRAL KANSAS INTO FAR NORTHWEST OKLAHOMA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MISSISSIPPI...CENTRAL ALABAMA...AND SOUTHERN GEORGIA...

...SUMMARY...
Severe thunderstorms capable of all severe hazards are expected this
afternoon and evening across portions of the central and southern
Plains. Several strong to intense tornadoes are possible.

...20z Update...
Adjustments were made to the current D1 Convective Outlook to the
Slight across the Southeast to account for latest trends in radar
and observations. A couple of broken line segments of thunderstorms
continue to pose a risk for damaging wind in these regions.

Elsewhere, the higher risk area across the central and southern
Plains continues to be where potential for all hazards will be
possible. The current plume of mid-level cloud cover extending from
central to eastern OK into southern KS continues to pose some
uncertainty on how the situation will unfold this afternoon.
Clearing across southwestern OK has allowed for heating and the
agitated cu field continues on visible satellite imagery. Further
into Kansas, clouds are more persistent but there is a narrow region
of warming from the Oklahoma Panhandle into Dodge City. CAM guidance
is spread on exactly how storms will evolve this afternoon, but it
appears supercell development is likely across the dryline in
western Oklahoma and Kansas this afternoon. Should a discrete mode
maintain, very large hail and tornadoes will be possible. As the afternoon/evening progresses, the low level jet will increase
through time with moisture advection increasing into central
Oklahoma and southern Kansas. Should supercells be maintained, this
could pose a risk for a strong tornado.

See previous discussion for more information.

..Thornton.. 05/18/2025

.PREV DISCUSSION... /ISSUED 1222 PM CDT Sun May 18 2025/

...KS/OK...
A large upper trough continues to deepen over the western US, with a
band of 60-70 knot southwesterly mid-level flow extending across NM
into western KS/OK. The surface dryline will mix eastward into
western KS and along the TX/OK border by mid-afternoon, with the air
mass to the east becoming extremely unstable with dewpoints in the
upper 60s and MLCAPE values over 4000 J/kg. Strong
southerly/southeasterly low-level winds throughout the warm sector
will provide a conditionally favorable environment for intense
supercells capable of very large hail, damaging winds, and
tornadoes. However, morning model guidance continues to show
diverse solutions regarding coverage of convection later today.

The area of greatest confidence in storm development and intensity
will be near the warm front/dryline triple point over south-central
KS. Discrete supercell development appears likely here, with
forecast soundings showing favorable hodograph structures to promote
a risk of strong tornadoes. The MDT risk has been extending
slightly eastward along the warm front. Farther south along the
dryline in western OK, confidence in initiation is lower. However,
any storm that can form will be capable of all hazards.

...Western North TX...
Another region of higher confidence in convective initiation will be
over western north TX along the dryline. Hot surface temperatures
in vicinity of a dryline bulge will aid in storm development. These
storms will likely expand eastward and into southwest OK through the
evening, with very large hail and damaging winds possible.

...MS/AL/GA...
A narrow corridor of SLGT risk has been added for this afternoon
from eastern MS across central AL and southern GA. Multiple MCSs
are ongoing in this corridor, with associated outflow boundaries
present. These boundaries may be the focus for further development
this afternoon, with sufficient CAPE/shear combinations to pose a
risk of damaging winds in the strongest cells.

$$

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ACUS01 KWNS 190102
SWODY1
SPC AC 190100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Sun May 18 2025

Valid 190100Z - 191200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE CENTRAL PLAINS...

...SUMMARY...
Severe thunderstorms capable of all severe hazards remain possible
this evening across portions of the central and southern Plains.
Several strong to intense tornadoes are possible.

...01z Update...

500mb speed max is translating across northeast NM into southwest KS
early this evening. Left-exit region of this feature appears largely
supportive of an extensive corridor of strong/severe thunderstorms
across the central High Plains from northwest KS into western NE.
Over the last hour or so, multiple storm mergers have evolved into
more of a north-south band of convection from Sheridan County
NE-north of GLD. This developing MCS should propagate east over the
next several hours with an attendant risk for hail, wind, and
perhaps a few tornadoes -- especially with embedded supercells.

Farther southeast, roughly a half dozen isolated supercells arc from
Sheridan County KS to Woods County OK. 1km VAD winds are quite
strong across northern OK into central KS with 50kt common. 0-3km
SRH at VNX/DDC/ICT exhibit more than 500 m2/s2. As LLJ is expected
to remain focused into this portion of the plains it seems
reasonable that ongoing supercells should remain organized as they
track northeast, albeit into a less unstable air mass due to earlier convection. Tornado threat remains highest across this corridor
until updrafts begin to decouple from the boundary layer.

Southwest-northeast corridor of strong/severe thunderstorms is
expected to linger across much of west-central into north-central TX
this evening as adequate 500mb flow remains supportive of organized
updrafts.

..Darrow.. 05/19/2025

$$

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ACUS01 KWNS 190600
SWODY1
SPC AC 190558

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Mon May 19 2025

Valid 191200Z - 201200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
CENTRAL AND EASTERN OKLAHOMA INTO THE WESTERN OZARKS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN APPALACHIANS...

...SUMMARY...
Significant severe weather is likely from the central/southern
Plains into the the Ozarks today into tonight. All severe weather
hazards are expected, to include tornadoes (some potentially strong
to intense), very large hail, and severe winds.

...Synopsis...
A highly amplified large-scale trough will move gradually eastward
from the Rockies across the Plains through the period. Within the
base of the trough, an embedded shortwave trough and accompanying
70-kt midlevel speed maximum will overspread the southern and
central Plains. In response, a surface cyclone will deepen over
north-central Oklahoma, while a focused low-level jet gradually
strengthens along/east of a dryline extending southward from the
surface cyclone (west of the I-35 corridor).

...Central/Southern Plains into the Mid Mississippi Valley...
Along/east of the dryline, rich boundary-layer moisture (lower 70s
dewpoints) beneath steep midlevel lapse rates accompanying an EML
will contribute to strong/extreme surface-based buoyancy -- aided by
diurnal heating within cloud breaks. Ascent along the dryline,
augmented by the increasing midlevel ascent, will support convective development during the early afternoon west of the I-35 corridor.
Storms should quickly intensify into a mix of supercells (from far
southern KS southward) and organized clusters/line segments (further
north) as they encounter the extreme instability and 50+ kt of
effective shear. All severe hazards will be possible with this
activity, including very large hail, damaging winds, and tornadoes
(some possibly strong to intense).

Similarly, warm-sector storm development is expected farther east
across eastern Oklahoma and vicinity, given weak inhibition, rich boundary-layer moisture, and the aforementioned large-scale ascent.
Despite the potential for scattered to numerous storms, the high-end environment will support long-track, semi-discrete supercells and
organized clusters capable of all severe hazards. While overall
convective evolution is somewhat uncertain, a 50-kt low-level jet
and related large clockwise-curved hodographs (200-300+ 0-1km SRH)
should support an increasing risk of strong/intense tornadoes during
the late afternoon into the evening hours. Storms will generally
spread/develop east-northeastward into the Mid-Mississippi Valley
into the overnight hours, and gradual upscale growth into several
organized clusters is possible -- with a continued all-hazards
severe risk.

...Southern Appalachians...
Along the northern periphery of shortwave ridging over the
Southeast, a midlevel jet streak will cross the southern
Appalachians during the afternoon. Here, an influx of steep midlevel
lapse rates atop rich boundary-layer moisture will yield strong
surface-based instability along/south of a warm front draped across
the region. Scattered thunderstorms will spread east-southeastward
along/south of the front from TN into the southern Appalachians,
where the favorable buoyancy and around 40-50 kt of effective shear
will promote organization into clusters and a couple splitting
supercell structures. Damaging winds and large hail will be possible
with the strongest storms.

..Weinman/Darrow.. 05/19/2025

$$

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ACUS01 KWNS 191253
SWODY1
SPC AC 191251

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 AM CDT Mon May 19 2025

Valid 191300Z - 201200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FAR NORTH
TEXAS...MUCH OF CENTRAL AND EASTERN OKLAHOMA...SOUTHEAST
KANSAS...AND THE OZARKS...

...SUMMARY...
Significant severe weather is likely from the central/southern
Plains into the the Ozarks today into tonight. All severe weather
hazards are expected, to include tornadoes (some potentially strong
to intense), very large hail, and severe winds.

... Synopsis ...

A large, amplified trough over the Rockies will shift slowly
eastward into the Plains today. Embedded within this longwave
trough, a complex evolution is expected. Downstream of the trough, a
negatively tilted shortwave trough will deepen and close off across
the northern Plains. Meanwhile, upstream, a closed low currently
over Idaho will dig southeastward, open up, and eject into the
central Plains.

As this evolution occurs, strong midlevel flow (in excess of 50
knots) will remain across much of the central and southern Plains
through the forecast period. By late in the afternoon, midlevel flow
will strengthen to perhaps 70 knots in response to the ejecting low
into the central Plains.

At the surface, the main synoptic low will be somewhat
diffuse/elongated over northwest Kansas into southwest Nebraska this
morning. Extending southward from this low, a dryline will stretch
through western Kansas into the Oklahoma and Texas Panhandles,
continuing into west Texas. A warm front will extend eastward near
the Kansas-Nebraska border before curving southeastward into
Missouri into the southern Appalachians.

The surface low is expected to gradually fill today as it slowly
moves east/northeast into south-central Nebraska, Despite this, rich
Gulf moisture will be maintained across the central and southern
Plains. Dewpoint temperatures at or above 70F will advect northward
from Texas through Oklahoma perhaps to as far north as northeast
Kansas.

During the afternoon, strong diurnal heating along the dryline may
result in a sub-synoptic low developing across northwest Oklahoma.
This low will slowly progress east along the Oklahoma-Kansas border
during the afternoon, weakening with time.

... Southern and Central Plains into the Ozarks ...

A strongly sheared atmosphere will already be in place at the start
of the forecast period. As diurnal heating commences and 70F
dewpoints advect northward, the atmosphere across much of the
central and southern Plains will become strongly to extremely
unstable as well, with surface-based CAPE values between 3000-5000
J/kg across the region.

Multiple rounds of storms are expected across the region today. One
such initiating mechanism looks to be a subtle shortwave trough
embedded in the larger scale flow currently across eastern New
Mexico. This wave should initiate thunderstorms across eastern
Oklahoma northward into eastern Kansas by midday. It is unclear if
these storms will initially be elevated, but as they move east and
the atmosphere destabilizes further ahead of the line, a transition
to more surface-based convection should occur. At the same time, the
low-level jet is forecast to strengthen/reorganize across eastern Oklahoma/western Arkansas into western Missouri. This will yield
ample low-level curvature to the hodograph. Thus, given the strongly
sheared environment in place, supercells capable of producing all
severe hazards, including strong tornadoes, will be possible with
this first round of storms.

By mid-to-late afternoon, 30-60 meter mid-level height falls should
overspread the dryline as it mixes east into central Kansas
southward into western north Texas. Rapid thunderstorm development
is expected along the dryline given the forecast extreme
instability. These thunderstorms should develop west of the better
low-level jet/flow, where the low-level flow is expected to be a
little more veered than across eastern Kansas/Oklahoma. This veered
low-level flow still will result in a strongly sheered environment,
but with more straight hodographs and less low-level curvature. The
result should be another round of supercells, albeit with a tendency
to split. These supercells will be capable of producing very large
hail and tornadoes. The number of supercells across the dryline
combined with a propensity to split, may result in destructive
interference and result in a more episodic hail and tornado threat.

In addition to the hail and tornado threat, the number of expected thunderstorms in the presence of a very moist and unstable
atmosphere with steep lapse rates may result in strong downdraft
winds. The most likely region for this will be across portions of
northeast Oklahoma, northwest Arkansas, southeast Kansas, and
southwest Missouri. A 45% wind area was included in this outlook.

... Southern Illinois into Southern Appalachians ...

Along the northern periphery of shortwave ridging over the
Southeast, a midlevel jet streak will cross the southern
Appalachians during the afternoon. Here, an influx of steep midlevel
lapse rates atop rich boundary-layer moisture will yield strong
surface-based instability along/south of a warm front draped across
the region. Scattered thunderstorms will spread east-southeastward
along/south of the front from TN into the southern Appalachians,
where the favorable buoyancy and around 40-50 kt of effective shear
will promote organization into clusters and a couple splitting
supercell structures. Damaging winds and large hail will be possible
with the strongest storms.

Overnight, additional thunderstorms may develop across southern
Illinois and western Kentucky in association with warm-air advection
ahead of the main area of thunderstorms to the west. These
thunderstorms will also pose the potential for small hail and
isolated wind damage.

..Marsh/Smith.. 05/19/2025

$$

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ACUS01 KWNS 191631
SWODY1
SPC AC 191630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Mon May 19 2025

Valid 191630Z - 201200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS FAR NORTH TEXAS...MUCH OF CENTRAL AND EASTERN OKLAHOMA...SOUTHEAST KANSAS...AND THE OZARKS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EAST
TENNESSEE INTO SOUTH CAROLINA...

...SUMMARY...
Significant severe weather is likely from the central/southern
Plains into the the Ozarks today into tonight. All severe weather
hazards are expected, to include tornadoes (some potentially strong
to intense), very large hail, and severe winds.

A powerful upper trough over the southern Rockies will eject into
the Plains today, with an associated 70-80 knot mid level jet nosing
into OK. Meanwhile, the primary surface low will deepen over
northwest OK and a southerly low-level jet will strengthen across
the warm sector. The resulting synoptic pattern is very favorable
for significant severe weather over portions of OK/AR/MO/KS, with
the potential for strong tornadoes, very large hail, and widespread
damaging winds. However, the mesoscale details of the forecast
result in considerable uncertainty regarding the corridors of
greatest risk.

...Eastern OK/Western AR/Southwest MO...
A southern stream shortwave trough over TX will track northeastward
today. Large scale ascent ahead of this feature will weaken the cap
and likely lead to rather widespread convective development by early
afternoon over much eastern OK and western AR. Forecast soundings
in this area show a very unstable air mass and favorable low and
deep layer shear profiles for supercell development. All severe
hazards are possible, including strong tornadoes. Refer to MCD #874
for further details.

...North TX/Central OK/Eastern KS/southeast NE...
Behind the aforementioned convective development, a pronounced
dryline will become established from west-central OK into central
KS. Strong heating along and west of the dryline, combined with
dewpoints near 70f to the east, will result in extreme instability
and only a weak cap. Large-scale mid-level height falls/forcing for
ascent associated with the approaching upper trough over the
southern Rockies will lead to discrete/intense supercell development
by mid/late afternoon - potentially along the entire length from
north TX into KS. These storms will pose a risk of very large hail
and strong tornadoes through the early evening.

Farther north in northeast KS and southeast NE, the Pacific cold
front will impinge on the dryline, aiding convective development but
perhaps leading to more linear forcing. Nevertheless, large hail
and tornadoes will still be possible.

..Hart/Moore.. 05/19/2025

$$

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ACUS01 KWNS 191953
SWODY1
SPC AC 191952

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0252 PM CDT Mon May 19 2025

Valid 192000Z - 201200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS FAR NORTH TEXAS...MUCH OF CENTRAL AND EASTERN OKLAHOMA...SOUTHEAST
KANSAS...NORTHWEST ARKANSAS...AND SOUTHWEST MISSOURI...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EAST
TENNESSEE INTO WESTERN SOUTH CAROLINA...

...SUMMARY...
Significant severe weather is likely from the central/southern
Plains into the the Ozarks today into tonight. All severe weather
hazards are expected, to include tornadoes (some potentially strong
to intense), very large hail, and severe winds.

...20Z Update...
A regional outbreak of severe thunderstorms is still anticipated
this afternoon and evening as a shortwave trough ejecting from the central/southern High Plains into the central/southern Plains, where
a very moist and unstable airmass is in place. Recent surface
analysis shows low 70s dewpoints across much of central and eastern
OK, with mid 60s dewpoints as far north as southeast NE. Both the
18Z OUN and OAX soundings sampled cold mid-level temperatures and
associated steep mid-level lapse rates. Ample moisture beneath these
steep lapse rates is supporting very strong buoyancy. 18Z OUN
sounding reported MLCAPE over 3500 J/kg.

Storms that developed earlier this afternoon across central OK are
now moving into southeast KS. These storms have maintained their
elevated character thus far, but some transition to a more
surface-based character is possible as destabilization continues
downstream. More surface-based, cellular development has initiated
across south-central OK and adjacent far northeast OK. Airmass
downstream is favorable for storm maintenance as they track
east-northeastward. All severe hazards are possible with these
storms, including very large hail, strong wind gusts, and strong to
intense tornadoes.

Convergence along the dryline is modest now, but will likely
increase later this afternoon and evening. Expectation is for
another round of supercells capable of all hazards (i.e. very large
hail, strong wind gusts, and strong to intense tornadoes) moving
from southwest OK/far northwest TX into central/south-central OK and
adjacent north-central TX. Large-scale ascent will increase across
eastern KS and southeast NE as well, with thunderstorms capable of
all hazards expected across this region as well.

By this evening, there will likely be a nearly continuous line of
thunderstorms from southeast NE/southwest IA into north-central TX.
A mix of supercells and bowing segments will maintain the risk of
significant severe weather throughout the evening and tonight,
continuing into early tomorrow morning from the Mid-MS Valley into
the Arklatex.

Guidance has trended towards more favorable environmental conditions
for a greater severe risk across southeast MO tonight, Wind and
tornado probabilities were increased across this region as a result.

..Mosier.. 05/19/2025

.PREV DISCUSSION... /ISSUED 1130 AM CDT Mon May 19 2025/

A powerful upper trough over the southern Rockies will eject into
the Plains today, with an associated 70-80 knot mid level jet nosing
into OK. Meanwhile, the primary surface low will deepen over
northwest OK and a southerly low-level jet will strengthen across
the warm sector. The resulting synoptic pattern is very favorable
for significant severe weather over portions of OK/AR/MO/KS, with
the potential for strong tornadoes, very large hail, and widespread
damaging winds. However, the mesoscale details of the forecast
result in considerable uncertainty regarding the corridors of
greatest risk.

...Eastern OK/Western AR/Southwest MO...
A southern stream shortwave trough over TX will track northeastward
today. Large scale ascent ahead of this feature will weaken the cap
and likely lead to rather widespread convective development by early
afternoon over much eastern OK and western AR. Forecast soundings
in this area show a very unstable air mass and favorable low and
deep layer shear profiles for supercell development. All severe
hazards are possible, including strong tornadoes. Refer to MCD #874
for further details.

...North TX/Central OK/Eastern KS/southeast NE...
Behind the aforementioned convective development, a pronounced
dryline will become established from west-central OK into central
KS. Strong heating along and west of the dryline, combined with
dewpoints near 70f to the east, will result in extreme instability
and only a weak cap. Large-scale mid-level height falls/forcing for
ascent associated with the approaching upper trough over the
southern Rockies will lead to discrete/intense supercell development
by mid/late afternoon - potentially along the entire length from
north TX into KS. These storms will pose a risk of very large hail
and strong tornadoes through the early evening.

Farther north in northeast KS and southeast NE, the Pacific cold
front will impinge on the dryline, aiding convective development but
perhaps leading to more linear forcing. Nevertheless, large hail
and tornadoes will still be possible.

$$

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ACUS01 KWNS 200101
SWODY1
SPC AC 200059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Mon May 19 2025

Valid 200100Z - 201200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN NORTHWEST ARKANSAS...SOUTHWEST MISSOURI...AND FAR EASTERN OKLAHOMA...

...SUMMARY...
A significant severe weather episode should continue tonight across
parts of the South-Central States. Strong tornadoes, scattered to
widespread damaging wind swaths, and very large hail remain
possible.

...TX/OK to the Mid-MS/Lower OH Valley...
While extensive overturning has already occurred, there are several
primary areas of concern for severe storms tonight. In the
near-term, the greatest tornado/wind potential should exist with a
pair of supercells embedded within a broad
southwest/northeast-oriented QLCS from the Ozark Plateau to the Red
River. With the most pronounced low-level shear ahead of this
portion of the QLCS, strong tornado and significant severe wind
potential should persist into late evening. Despite stronger
large-scale ascent focused west, the organized nature of the QLCS
suggests that embedded wind gusts of 60-75 mph could produce a
potentially widespread damaging wind swath that may persist
east-northeast overnight. Have expanded outlook categories farther
east across the Mid-MS/Lower OH Valley.

The trailing portion of the QLCS has been stubborn to accelerate
east, but should begin to do so in the next couple hours. Short-term
guidance has been insistent on additional convection developing back
west with strengthening ascent ahead of the primary shortwave trough
from central to eastern OK tonight. This could pose another round of
severe hail/wind threat persisting into the early morning.

...KS and the Lower/Mid-MO Valley...
Scattered severe storms should generally wane during the late
evening. But similar to the OK redevelopment, post-dryline/frontal
high-based convection should expand east-northeast and likely
impinge on lingering strong to severe storms across eastern KS. This
could maintain at least isolated severe storms lingering overnight.

..Grams.. 05/20/2025

$$

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ACUS01 KWNS 200556
SWODY1
SPC AC 200555

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Tue May 20 2025

Valid 201200Z - 211200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN THE MID/DEEP
SOUTH TO TN VALLEY AND CUMBERLAND PLATEAU...

...SUMMARY...
Multiple rounds of severe thunderstorms are expected today through
this evening, centered on the Mid/Deep South, Tennessee/Lower Ohio
Valleys, and Cumberland Plateau. Tornadoes, some of which could be
strong, along with scattered to widespread damaging winds, and large
to isolated significant severe hail will be possible.

...Synopsis...
Multiple shortwave impulses and attendant mid-level jetlets will
rotate through the southern to eastern portion of the broad
mid/upper trough over the central states. A belt of 60-75 kt 500-mb southwesterlies should be centered on the Ark-La-Tex to Lower OH
Valley by late afternoon. This should weaken thereafter, as the next
shortwave impulse strengthens flow across the central Great Plains
by evening. Primary surface cyclone should initially drift east from
the IA/MO border into IL through the day, before accelerating
eastward across IN/OH tonight.

...Mid/Deep South to the TN/Lower OH Valleys and Cumberland
Plateau...
An extensive swath of convection, currently from the Mid-MS Valley
to the Red River, will likely be ongoing across parts of KY to the
Ark-La-Miss at 12Z. The northern portion of this convective swath is consistently progged to persist into the diurnal heating cycle,
aided by low-level warm theta-e advection along with mid-level
height falls, and downstream destabilization. The latter is a
primary source of uncertainty given the outpacing of convection thus
far relative to 00Z CAM guidance. It does appear that there should
be at least modest surface-based buoyancy being maintained
downstream to warrant potential for a severe-producing QLCS into the
afternoon. All severe threats are possible, but damaging winds may
be the predominant coverage hazard. Tornado potential should peak
where the QLCS approaches the surface warm front, before an abrupt
drop-off in surface-based instability to its northeast.

Greater boundary-layer destabilization is expected to the
west-southwest of the early-day activity with relatively rapid
airmass recovery amid low 70s surface dew points. Mid-level lapse
rates will initially be steep over the Mid-MS Valley, but be more
muted with southern extent into the Lower MS Valley. Still, moderate
to large buoyancy with MLCAPE of 2000-3000 J/kg and minimal MLCIN
should be common by mid-late afternoon. During that time frame,
scattered supercells will likely develop along and just ahead of the eastward-moving cold front from the Lower OH Valley to the
Ark-La-Miss. The modest mid-level lapse rates will be a limiting
factor, but isolated significant severe hail (up to around tennis
ball-size) will be possible in the initial supercell corridor. A
broad swath of 30-40 kt low-level southwesterlies should be
sufficient for at least a few strong tornadoes as supercells mature,
most likely from western/southern KY across TN into northern
portions of MS/AL. Guidance is insistent on upscale growth by early
evening though, which would yield small-scale bows and potentially
multiple damaging wind swaths. Embedded supercells should still
persist well into the evening as storms spread east-southeast in the
Southeast and southern Appalachians. But the aforementioned relative
decrease in mid-level winds and muted lapse rates lower confidence
on significant severe wind and greater tornado probability
highlights.

...IL/IN...
Within the left-exit region of the aforementioned mid-level jetlet,
a dry slot and attendant corridor of steep lapse rates will likely
evolve across portions of MO to IL/IN from midday into the
afternoon. To the north of this, a cluster of sustained storm
development is initially anticipated towards mid-afternoon, centered
on central IL ahead of the surface low. Additional storms should
develop farther south in time towards the Lower OH Valley. A mix of
supercells and multicell clustering is anticipated, with isolated to
scattered coverage of severe and all hazards possible.

..Grams/Weinman.. 05/20/2025

$$

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