Forum: Too Lazy BBS

DAY1SVR: Day 1 Convective Outlook

From COD Weather Processor @1:2320/107 to All on Thu Aug 13 12:40:16 2026

ACUS01 KWNS 131240
SWODY1
SPC AC 131238

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0738 AM CDT Thu Aug 13 2026

Valid 131300Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL IOWA
INTO EAST-CENTRAL ILLINOIS...

...SUMMARY...
Isolated to scattered severe thunderstorms are possible today from
parts of the southern/central High Plains to the mid Mississippi and
lower Ohio Valleys. Severe gusts capable of wind damage should be
the main threat, but occasional hail may also occur.

...Iowa into Illinois/Indiana...
Radar mosaic/IR imagery loops show a long-lived MCS over central IA
moving east towards the MS River this morning. Widely scattered
severe gusts 60-70 mph are possible with the more intense bowing
structures and short-lived mesovortices embedded within the line,
along with a brief tornado risk (for short-term details, reference
MCD #1966). This activity will continue into IL but limited
confidence regarding its evolution and subsequent severe risk cast
uncertainty whether it will reinvigorate or additional strong/severe
storms will develop on the leading edge of outflow. Regardless, a
moist airmass across the eastern Corn Belt will destabilize amid a
veil of high clouds. Forecast model guidance shows 35-45 effective
shear supporting organized storms. Isolated to scattered damaging
gusts will be the primary severe hazard, although a brief tornado
and marginally severe hail are also possible through the early
evening.

...Southern/Central High Plains...
High-based thunderstorms are forecast to initially develop over the
higher terrain of the central Rockies/Front Range this afternoon,
with post-frontal low-level upslope flow persisting across the
central High Plains. Storm motions into slightly richer moisture
will favor some aggregation of outflow within a hot boundary layer
featuring steep lapse rates. Isolated to widely scattered severe
gusts 60-75 mph are possible, along with occasional hail with a few
of the stronger cores that develop. It seems possible a
smaller-scale area within this broad region may focus a slightly
more concentrated severe-wind threat. However, given the modest
large-scale forcing mechanisms and marginal deep-layer shear for
storm organization, will defer higher severe-wind probabilities for
the time being.

...Great Basin...
Modestly enhanced southwesterly mid-level flow will persist today
across the Great Basin downstream of a weak mid-level trough over
CA. Weak to locally moderate instability is forecast via diurnal
heating. Scattered to numerous thunderstorms are expected and some
of the stronger evaporatively cooled downdrafts will be capable of
60-75 mph gusts.

...Northeast...
Seasonably cool mid-level temperatures are forecast today across
parts of the Northeast, with a mid-level trough expected to move east-southeastward from Quebec into New England. While instability
is forecast to remain fairly limited, strong west-northwesterly flow
aloft may support a risk for isolated damaging winds (50-65 mph)
with thunderstorms that develop and spread southeastward through the
afternoon. Isolated hail may also occur with the stronger cells.

..Smith/Kerr.. 08/13/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 13 16:34:16 2026

ACUS01 KWNS 131634
SWODY1
SPC AC 131632

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1132 AM CDT Thu Aug 13 2026

Valid 131630Z - 141200Z

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

...SUMMARY...
Isolated to scattered severe thunderstorms are possible today from
parts of the southern/central High Plains to the Midwest. Severe
wind gusts should be the main threat, but some hail may also occur.

...Midwest including parts of eastern Iowa and Illinois/Indiana...
Supported by an MCV, a long-lived MCS continues to move
east-southeastward into west-central/northwest Illinois late this
morning. Greater stability initially precedes the MCS across
northern Illinois, but the remnant cluster and additional
redevelopment will likely tend to favor a more southeastward
progression in closer proximity to the front/instability gradient
that extends across Illinois/Indiana, with additional/renewed
development and intensification possible into the afternoon and
evening. Damaging wind gusts will be the primary severe hazard,
although a brief tornado and marginally severe hail are also
possible into this evening. While not certain, additional severe
redevelopment may also occur tonight farther west/northeastward
across areas potentially including eastern Iowa and northern/central
Illinois as a low-level jet nocturnally increases.

...Southern/Central High Plains...
High-based thunderstorms are expected to initially develop over the
higher terrain of the central Rockies/Front Range this afternoon,
with post-frontal low-level upslope flow persisting across the
central High Plains. Storm motions into slightly richer moisture
will favor some aggregation of outflow within a hot boundary layer
featuring steep lapse rates. Isolated to widely scattered severe
wind gusts 60-75 mph are possible, along with occasional hail with a
few of the stronger cores.

...Great Basin...
Modestly enhanced southwesterly mid-level flow will persist today
across the Great Basin downstream of a weak mid-level trough over
California. Weak to locally moderate instability is forecast via
diurnal heating. Scattered to numerous thunderstorms are expected
and some of the stronger evaporatively cooled downdrafts will be
capable of 60-75 mph gusts.

...Northeast...
Seasonably cool mid-level temperatures are forecast today across
parts of the Northeast, with a mid-level trough expected to move east-southeastward from Quebec into New England. While instability
is forecast to remain fairly limited, strong west-northwesterly flow
aloft may support a risk for isolated damaging winds (50-65 mph)
with thunderstorms that develop and spread southeastward through the
afternoon. Isolated hail may also occur with the stronger cells.

..Guyer/Chalmers.. 08/13/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 13 19:58:18 2026

ACUS01 KWNS 131958
SWODY1
SPC AC 131956

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0256 PM CDT Thu Aug 13 2026

Valid 132000Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE MIDWEST INTO THE OHIO VALLEY...

...SUMMARY...
Isolated to scattered severe thunderstorms remain possible today
from parts of the southern/central High Plains to the Midwest.
Severe wind gusts should be the main threat, but some hail may also
occur.

...20Z Update...
The main change made to the 20Z Day 1 Convective Outlook Update was
to add 5 percent hail probabilities across portions of central NV
given modestly cold temperatures aloft and accompanying 7.5-8 C/km
mid-level lapse rates. There were considerations to trim or remove
the Slight Risk across portions of the Midwest behind the ongoing
cluster of thunderstorms. However, recovery along a residual
baroclinic boundary, overspread by 2000+ J/kg MLCAPE and 40+ kts of
effective bulks shear, may support additional storm development
later this evening when the LLJ intensifies. Otherwise, the previous
forecast remains on track, with only minor changes made to ongoing
thunder and severe probabilities to account for the latest guidance
consensus.

..Squitieri.. 08/13/2026

.PREV DISCUSSION... /ISSUED 1132 AM CDT Thu Aug 13 2026/

...Midwest including parts of eastern Iowa and Illinois/Indiana...
Supported by an MCV, a long-lived MCS continues to move
east-southeastward into west-central/northwest Illinois late this
morning. Greater stability initially precedes the MCS across
northern Illinois, but the remnant cluster and additional
redevelopment will likely tend to favor a more southeastward
progression in closer proximity to the front/instability gradient
that extends across Illinois/Indiana, with additional/renewed
development and intensification possible into the afternoon and
evening. Damaging wind gusts will be the primary severe hazard,
although a brief tornado and marginally severe hail are also
possible into this evening. While not certain, additional severe
redevelopment may also occur tonight farther west/northeastward
across areas potentially including eastern Iowa and northern/central
Illinois as a low-level jet nocturnally increases.

...Southern/Central High Plains...
High-based thunderstorms are expected to initially develop over the
higher terrain of the central Rockies/Front Range this afternoon,
with post-frontal low-level upslope flow persisting across the
central High Plains. Storm motions into slightly richer moisture
will favor some aggregation of outflow within a hot boundary layer
featuring steep lapse rates. Isolated to widely scattered severe
wind gusts 60-75 mph are possible, along with occasional hail with a
few of the stronger cores.

...Great Basin...
Modestly enhanced southwesterly mid-level flow will persist today
across the Great Basin downstream of a weak mid-level trough over
California. Weak to locally moderate instability is forecast via
diurnal heating. Scattered to numerous thunderstorms are expected
and some of the stronger evaporatively cooled downdrafts will be
capable of 60-75 mph gusts.

...Northeast...
Seasonably cool mid-level temperatures are forecast today across
parts of the Northeast, with a mid-level trough expected to move east-southeastward from Quebec into New England. While instability
is forecast to remain fairly limited, strong west-northwesterly flow
aloft may support a risk for isolated damaging winds (50-65 mph)
with thunderstorms that develop and spread southeastward through the
afternoon. Isolated hail may also occur with the stronger cells.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 14 01:02:18 2026

ACUS01 KWNS 140102
SWODY1
SPC AC 140100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Thu Aug 13 2026

Valid 140100Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
NORTH-CENTRAL ILLINOIS INTO SOUTHWEST OHIO...

...SUMMARY...
Thunderstorms with severe wind gusts and hail will be possible
tonight from parts of north-central Illinois into southwest Ohio.
Severe gusts and hail will be possible in parts of the central
Plains. A few severe gusts may also occur in parts of the
Intermountain West.

...Mid Mississippi and Ohio Valleys/Southern Great Lakes...
The latest water vapor imagery shows a mid-level anticyclonic flow
pattern over the central U.S., with west-northwesterly flow located
over the eastern U.S. At the surface, a quasi-stationary front is
analyzed from northeast Missouri to northern Kentucky. Surface
dewpoints along and to the south of the front are in the 70s and low
80s F, which is contributing a west-northwest to east-southeast axis
of strong instability. The RAP has MLCAPE along this axis in the
3000 to 5000 J/kg range. To the north of the instability axis,
short-term model forecasts move a subtle shortwave trough
east-southeastward through the Midwest tonight. Large-scale ascent
associated with the trough coupled with increasing low-level flow
will likely result in the development of a line of strong storms.
This is forecast to take place late this evening, with the line
moving southeastward from north-central Illinois across central
Indiana and into southwest Ohio. Severe wind gusts will be possible
with this line segment.

...Central Plains...
Southwesterly mid-level flow is currently in place over much of the southwestern and central U.S. An embedded mid-level shortwave trough
appears to be moving into the central High Plains. Ahead of this
feature, the RAP has an axis of moderate instability located from
northern and western Kansas into northeastern Colorado, along which
MLCAPE is estimated in the 1500 to 2500 J/kg range. Scattered
thunderstorms were ongoing near the instability axis early this
evening in eastern Colorado with another cluster in central Kansas.
Increasing low-level flow from this evening into the overnight
period will likely sustain convective development. Hail and isolated
severe wind gusts will be possible with the stronger cells.

...Intermountain West...
On water vapor imagery, multiple shortwave troughs appear to be
moving through the Intermountain West. Ahead of these features,
scattered thunderstorms are ongoing across much of Nevada and Utah.
The RAP is currently analyzing an axis of instability from southeast
Nevada into north-central Utah along which MLCAPE is estimated to be
in the 750 to 1000 J/kg range. Near the instability axis, the RAP
also has low to mid-level lapse rates in the 7.5 to 8.5 C/km range.
This thermodynamic environment should support an isolated potential
for severe wind gusts this evening.

..Broyles.. 08/14/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 14 05:59:56 2026

ACUS01 KWNS 140559
SWODY1
SPC AC 140557

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1257 AM CDT Fri Aug 14 2026

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID MISSOURI AND MID MISSISSIPPI VALLEYS...

...SUMMARY...
Thunderstorms with severe wind gusts and hail will be possible this
afternoon and evening across parts of the mid Missouri and mid
Mississippi Valleys. Isolated severe gusts will also be possible in
parts of the central Plains and from the Ohio Valley to the
Mid-Atlantic.

...Mid Missouri and mid Mississippi Valleys...
A broad anticyclonic flow pattern will be in place over much of the
central U.S. today, as a subtle embedded shortwave trough moves
through the mid Missouri Valley. Ahead of this feature, a
quasi-stationary front will be in place from southern Iowa
east-southeastward into north-central Illinois. This boundary will
be the focus for convective development this afternoon. Surface
dewpoints along the boundary will be in the 70s F, which will result
in strong destabilization by afternoon. Surface-based convective
initiation is expected along the instability gradient during the
late afternoon to the south of Omaha. From these initial storms, a
line is expected to organize and move eastward across south-central
Iowa and far northern Missouri during the late afternoon and early
evening.

RAP forecast soundings ahead of the line at 00Z from Des Moines
southward into far northern Missouri have MLCAPE in the 2000 to 3500
J/kg range. Some directional shear is present in the low-levels, and
0-6 km shear is in the 30 to 35 knot range. This environment will be
favorable for bowing line segments capable of severe wind gusts. An
embedded supercell with a hail threat will also be possible. The
severe threat is expected to move eastward into northwest and
north-central Illinois during the evening.

...Central Plains...
Southwesterly mid-level flow will be in place today over much of the
western and central U.S. A subtle shortwave trough will move
northeastward into the central High Plains. Large-scale ascent
associated with the trough and topographic lift in the foothills of
the Rockies will be favorable for scattered convective initiation by
early afternoon. Thunderstorms will move northeastward into the
central High Plains and into a moderately unstable airmass. Some RAP
forecast soundings in east-central Colorado during the late
afternoon have 0-6 km shear around 25 knots with low to mid-level
lapse rates exceeding 7 C/km. This will likely support isolated
severe wind gusts and hail.

...Ohio Valley/Central Appalachians/Mid-Atlantic...
West-northwesterly mid-level flow will be in place today over much
of the northeastern U.S. At the surface, an axis of moderate
instability will develop by afternoon from the Ohio Valley
east-southeastward into the Mid-Atlantic. Along and near the
instability axis, low-level convergence will be the primary focus
for convective initiation. Near and downstream of these pockets of
convergence, isolated to scattered thunderstorms are expected to
develop. The moderate instability with precipitable water values in
the 2 to 2.2 inch range should support a threat for isolated severe
wet downbursts.

..Broyles/Lyons.. 08/14/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 14 12:49:20 2026

ACUS01 KWNS 141249
SWODY1
SPC AC 141247

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0747 AM CDT Fri Aug 14 2026

Valid 141300Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
MID MISSOURI AND MID MISSISSIPPI VALLEYS...

...SUMMARY...
Strong to severe thunderstorms will be possible this afternoon and
evening across parts of the mid Missouri and mid Mississippi
Valleys. Isolated severe gusts will also be possible in parts of the
central Plains and from the Ohio Valley to the Mid-Atlantic.

...Mid Missouri and mid Mississippi Valleys...
An extensive band of showers and thunderstorms currently extends
from northeast NE southeastward across central IA, central IL, and
central IN. These showers and thunderstorms have been supported by
warm-air advection across a relatively broad/diffuse frontal zone
extending from southeast NE east-southeastward across northern MO
and southern IL. Overall coverage and intensity of these showers and thunderstorms is forecast to gradually wane throughout the morning
as the low-level jet responsible for the warm-air advection weakens.

Primary severe risk across this region today will be linked to the
amount of air mass recovery and associated destabilization that
occurs along the southern periphery of this band, ahead of a
well-defined MCV generated by overnight convection across KS and NE.
Ample low-level moisture is in place, and differential heating
between the residual cloud debris from the early morning storms
could result in a warm-front-like zone across southern IA or
northern MO. Where this boundary sets up, its strength, and its
location all still remain uncertain this morning, largely due to the
limited predictability of how the ongoing precipitation evolves. The
airmass along and south of this boundary is forecast to destabilize
and become moderately to strongly unstable by the late afternoon.
Additionally, low-level convergence along this boundary should be
augmented by mesoscale ascent attendant to the MCV progressing
through the region. The resulting combination of lift and buoyancy
will support thunderstorm development. A belt of stronger mid-level
flow could accompany the MCV, resulting in enough deep-layer shear
to support organized storm structures with any persistent updrafts.
Strong gusts associated with water-loaded downdrafts, as well as
with any bowing segments, are the primary severe risk. Presence of
the boundary coupled with southeasterly low-level flow will also
support the potential for a brief tornado, particularly early in the
convective cycle when a more cellular mode is likely.

...Ohio Valley/Central Appalachians/Mid-Atlantic...
Showers and thunderstorms are ongoing from IL into OH. These showers
and thunderstorms will likely weaken this morning but associated
cloud cover could reinforce a modest baroclinic zone that extends
from southern IL across southern IN/southern OH and through central
WV/central VA. A modest vorticity max over central IL is forecast to
progress southeast within the west-northwesterly mid-level flow
along and north of this boundary today. Ascent attendant to this
vorticity maximum coupled with low-level convergence and afternoon
airmass destabilization will support renewed thunderstorm
development. Vertical shear will be weak, but strong updrafts and
ample moisture could result in a threat for wet microbursts.

...Central High Plains...
A shortwave trough currently moving through the Lower CO River
Valley is forecast to continue northeastward through the Four
Corners. Ascent associated with this wave will combine with
orographic lift in the foothills of the Rockies to support scattered
convective initiation by early afternoon. Thunderstorms will then
move northeastward into the moderately buoyant airmass over the
central High Plains. Deep-layer shear will be modest but sufficient
for a few organized updrafts capable of hail and damaging gusts.

...Southern NV Vicinity...
Dewpoints are in the 60s across southern CA, the Lower CO River
Valley, and southern AZ. Strong heating will support afternoon
airmass destabilization, combining with the moisture in place to
support moderate buoyancy. Slightly stronger mid-level flow is
anticipated over the southern NV vicinity, supporting the potential
for isolated strong gusts.

..Mosier/Dean.. 08/14/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 14 16:45:24 2026

ACUS01 KWNS 141645
SWODY1
SPC AC 141643

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1143 AM CDT Fri Aug 14 2026

Valid 141630Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
MIDWEST...

...SUMMARY...
Severe thunderstorms will be possible this afternoon and evening
across parts of the middle Missouri and middle Mississippi Valleys.
Isolated severe wind gusts will also be possible in parts of the
central Plains and from the Ohio Valley to the Mid-Atlantic, as well
as parts of the Northeast and Southwest.

...Mid Missouri and mid Mississippi Valleys...
Thunderstorms have largely weakened through the early morning across
the middle Missouri Valley, with more of a lingering persistence
across Illinois/Indiana. Scattered showers remain rather common,
however, regionally with semi-prevalent cloud cover. Multiple MCVs
persist regionally at midday, including across central Iowa, and
more prominently near the Nebraska/Iowa border. Regional WSR-88D
data from Omaha/Des Moines/Davenport continue to sample enhanced
westerlies (35-50 kt) between 4-8 km AGL in association with these
MCVs.

Primary severe risk across this region today will be linked to the
amount of air mass recovery and associated destabilization that
occurs along the southern periphery of the residual convection and
ahead of the aforementioned slow-moving MCVs. Ample low-level
moisture is in place, and differential heating between the residual
cloud debris may yield an effective warm-front-like zone across
southern Iowa or near the Iowa/Missouri border. The airmass along
and south of this is forecast to destabilize and become moderately
to strongly unstable by the late afternoon. This should result in
renewed thunderstorm development by late afternoon into evening,
with sufficient deep-layer shear to support organized updrafts and
potentially some initial supercells. Modestly enhanced low-level
winds/SRH could yield a tornado risk. Strong wind gusts will
otherwise be possible with water-loaded downdrafts, as well as with
any bowing segments through this evening.

...Ohio Valley/Central Appalachians/Mid-Atlantic...
Outflows/differential heating across the lower Ohio Valley will
influenced thunderstorm redevelopment this afternoon, while storms
are starting to develop/increase across the Appalachians vicinity.
Vertical shear will generally be weak, but strong updrafts and ample
moisture will yield the potential for wet microbursts regionally.

...Central High Plains...
A shortwave trough currently moving through the Lower Colorado River
Valley is forecast to continue northeastward through the Four
Corners. Ascent associated with this wave will combine with
orographic lift in the foothills of the Rockies to support scattered
convective initiation by early afternoon. Thunderstorms will then
move northeastward into the moderately buoyant airmass over the
central High Plains. Deep-layer shear will be modest but sufficient
for a few organized updrafts capable of hail and damaging gusts.

...Northeast States...
Influenced by strong northwesterly flow aloft, a few stronger to
locally severe relatively low-topped storms may occur this afternoon
across northern/upstate New York into southern New England, with
strong/gusty winds as the primary hazard as convection progresses southeastward.

...Lower Colorado River ...
With a moist air mass across the region, strong heating will support
afternoon airmass destabilization, yielding moderate buoyancy this
afternoon. Slightly stronger mid-level flow is anticipated over the
southern Nevada vicinity, supporting the potential for isolated
strong wind gusts.

..Guyer/Chalmers.. 08/14/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 14 19:56:56 2026

ACUS01 KWNS 141956
SWODY1
SPC AC 141955

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Fri Aug 14 2026

Valid 142000Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
MIDWEST...

...SUMMARY...
Severe thunderstorms remain possible this afternoon and evening
across parts of the middle Missouri and middle Mississippi Valleys.
Isolated severe wind gusts may also still occur in parts of the
central Plains and from the Ohio Valley to the Mid-Atlantic, as well
as parts of the Northeast and Southwest.

...20Z Update...
The previous forecast (see below) remains on track, with only minor
changes made to thunder and severe probabilities to reflect
observations and the latest guidance consensus.

..Squitieri.. 08/14/2026

.PREV DISCUSSION... /ISSUED 1143 AM CDT Fri Aug 14 2026/

...Mid Missouri and mid Mississippi Valleys...
Thunderstorms have largely weakened through the early morning across
the middle Missouri Valley, with more of a lingering persistence
across Illinois/Indiana. Scattered showers remain rather common,
however, regionally with semi-prevalent cloud cover. Multiple MCVs
persist regionally at midday, including across central Iowa, and
more prominently near the Nebraska/Iowa border. Regional WSR-88D
data from Omaha/Des Moines/Davenport continue to sample enhanced
westerlies (35-50 kt) between 4-8 km AGL in association with these
MCVs.

Primary severe risk across this region today will be linked to the
amount of air mass recovery and associated destabilization that
occurs along the southern periphery of the residual convection and
ahead of the aforementioned slow-moving MCVs. Ample low-level
moisture is in place, and differential heating between the residual
cloud debris may yield an effective warm-front-like zone across
southern Iowa or near the Iowa/Missouri border. The airmass along
and south of this is forecast to destabilize and become moderately
to strongly unstable by the late afternoon. This should result in
renewed thunderstorm development by late afternoon into evening,
with sufficient deep-layer shear to support organized updrafts and
potentially some initial supercells. Modestly enhanced low-level
winds/SRH could yield a tornado risk. Strong wind gusts will
otherwise be possible with water-loaded downdrafts, as well as with
any bowing segments through this evening.

...Ohio Valley/Central Appalachians/Mid-Atlantic...
Outflows/differential heating across the lower Ohio Valley will
influenced thunderstorm redevelopment this afternoon, while storms
are starting to develop/increase across the Appalachians vicinity.
Vertical shear will generally be weak, but strong updrafts and ample
moisture will yield the potential for wet microbursts regionally.

...Central High Plains...
A shortwave trough currently moving through the Lower Colorado River
Valley is forecast to continue northeastward through the Four
Corners. Ascent associated with this wave will combine with
orographic lift in the foothills of the Rockies to support scattered
convective initiation by early afternoon. Thunderstorms will then
move northeastward into the moderately buoyant airmass over the
central High Plains. Deep-layer shear will be modest but sufficient
for a few organized updrafts capable of hail and damaging gusts.

...Northeast States...
Influenced by strong northwesterly flow aloft, a few stronger to
locally severe relatively low-topped storms may occur this afternoon
across northern/upstate New York into southern New England, with
strong/gusty winds as the primary hazard as convection progresses southeastward.

...Lower Colorado River ...
With a moist air mass across the region, strong heating will support
afternoon airmass destabilization, yielding moderate buoyancy this
afternoon. Slightly stronger mid-level flow is anticipated over the
southern Nevada vicinity, supporting the potential for isolated
strong wind gusts.

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 15 01:02:00 2026

ACUS01 KWNS 150101
SWODY1
SPC AC 150059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Fri Aug 14 2026

Valid 150100Z - 151200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
THE CENTRAL PLAINS INTO THE MID MISSISSIPPI VALLEY...MID-ATLANTIC
AND INTERMOUNTAIN WEST...

...SUMMARY...
Thunderstorms with isolated severe wind gusts and hail will be
possible this evening into the overnight across parts of the mid
Missouri and mid Mississippi Valleys. Isolated severe gusts and hail
will also be possible in parts of the Mid-Atlantic, central Plains
and Intermountain West.

...Mid Missouri and Mid Mississippi Valleys...
The latest water vapor imagery shows a broad anticyclonic flow
pattern in place from the Great Plains to the Appalachians. An
embedded mid-level shortwave trough appears to be located from
south-central Iowa into far northwest Missouri. Ahead of this
feature, surface dewpoints across far southern Iowa and northern
Missouri are in the upper 70s F. The RAP currently has an
east-to-west corridor of strong instability in north-central
Missouri, where MLCAPE is estimated to be in the 3000 to 4000 J/kg
range. Along the instability gradient in northern Missouri,
low-level flow will increase this evening, fueling the development
of numerous thunderstorms. Some RAP forecast soundings near the
instability gradient this evening have effective shear in the 25 to
30 knot range with 850 to 500 mb lapse rates around 6.5 C/km. This
should support a hail threat with the stronger elevated storms. An
isolated potential for severe gusts may also develop if any of the
cells can remain surface-based. The severe threat is expected to
continue into the overnight period.

...Mid-Atlantic...
West-northwesterly mid-level flow is evident on water vapor imagery
over the eastern U.S. At the surface, dewpoints are in the 70s F
from the Mid-Atlantic southward into the Carolinas, where the RAP
has MLCAPE in the 2000 to 3000 J/kg range. Scattered thunderstorms
are ongoing along the northern edge of the stronger instability over
eastern Virginia. Near this convection, the WSR-88D VWP at Wakefield
has 0-6 km shear of 30 to 35 knots which could support a marginal
severe threat for another hour or two this evening. Severe wind
gusts and hail will be possible.

...Central Plains...
Southwesterly mid-level flow is currently in place over much of the
central U.S. At the surface, a quasi-stationary front is located
from eastern Colorado into central Kansas. Surface dewpoints near
the front are from the mid 60s to mid 70s F, and the RAP has MLCAPE
in the 2000 to 3000 J/kg range. Along the western edge of the
stronger instability, scattered thunderstorms are ongoing across
eastern Colorado. RAP forecast soundings just ahead of the storms
near the Colorado-Kansas state line this evening have 0-6 km shear
around 40 knots with 700-500 mb lapse rates around 7 C/km. This will
support a marginal severe threat. A few severe wind gusts and hail
will be possible with the stronger cells.

...Intermountain West...
Water vapor imagery currently shows southwesterly mid-level flow
over the Intermountain West with a subtle shortwave trough moving
into the region from the southwest. Ahead of this feature, an axis
of moderate instability is located from northwestern Arizona into
southeast Nevada, along which the RAP has MLCAPE in the 1000 to 1500
J/kg range. Scattered thunderstorms are ongoing near the instability
axis early this evening. RAP forecast soundings just downstream from
the storms early this evening have 0-6 km shear around 30 knots
along with 700-500 mb lapse rates near 7.5 C/km suggesting a
potential for isolated severe wind gusts.

..Broyles.. 08/15/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 15 06:01:58 2026

ACUS01 KWNS 150601
SWODY1
SPC AC 150559

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Sat Aug 15 2026

Valid 151200Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
OHIO VALLEY SOUTHEASTWARD INTO THE CAROLINAS...AND IN THE CENTRAL
HIGH PLAINS...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible from late afternoon into the evening across the central
High Plains. Severe wind gusts will also be possible this afternoon
into the early evening from parts of the Ohio Valley southeastward
into the Carolinas.

...Mid Mississippi and Ohio Valleys/Central
Appalachians/Carolinas...
At mid-levels today, a broad anticyclonic flow pattern will be in
place over the eastern U.S. Within the flow, a shortwave trough will
move eastward into the lower Ohio Valley. Ahead of this feature, a
moist and unstable airmass will be located from the mid Mississippi
Valley east-southeastward into the Ohio Valley and southern
Appalachians. In the morning, a convective complex is forecast to
move eastward into the southern Great Lakes, and will likely be
associated with a potential for severe wind gusts. To the south of
this complex, a quasi-stationary front and moist axis will be
located from the lower Ohio Valley southeastward into the southern Appalachians, along which moderate instability will develop by
afternoon. Low-level convergence near the front will be the focus
for convective development. A new complex of surface-based
thunderstorms appears likely to form near the front and move
east-southeastward from western Ohio into the Virginias during the
afternoon. Additional storms will develop along and near the
instability axis over the western Carolinas due to topographical
forcing.

Model forecasts in the moist air suggest that MLCAPE will peak in
the 2000 to 3000 J/kg range in most areas. Near the instability
axis, precipitable water values in the 1.8 to 2 inch range and
moderate deep-layer shear will likely support a threat for severe
wet downbursts. This threat should persist into the early evening
with any line segments that become sustained over the higher terrain
of the southern and central Appalachians.

...Central Plains...
West-southwesterly mid-level flow will be in place over the
southwestern and central U.S. today. At the surface, a moist airmass
will be located from the foothills of the Rockies eastward into the
central Plains. By afternoon, moderate instability will develop over
much of the region. Scattered thunderstorms will form in the higher
terrain and move eastward into the lower elevations during the mid
to late afternoon. Some RAP forecast soundings at 21Z from eastern
Colorado northward into western Nebraska have 0-6 km shear near 35
knots with steep low to mid-level lapse rates exceeding 7 C/km. This environment will support a mixed mode with supercells and multicell
line segments possible. Supercells should be capable of isolated
large hail, while severe wind gusts will be possible with supercells
and organized multicells. The severe threat should persist into the
early to mid evening as a complex of storms moves eastward through
the central High Plains.

..Broyles/Lyons.. 08/15/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 15 12:51:46 2026

ACUS01 KWNS 151251
SWODY1
SPC AC 151249

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0749 AM CDT Sat Aug 15 2026

Valid 151300Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL HIGH PLAINS AS WELL AS THE MIDDLE OHIO VALLEY...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible from late afternoon into the evening across the central
High Plains. Severe wind gusts will also be possible this afternoon
into the early evening across parts of the Ohio Valley.

...Central High Plains...
Relatively moist southwesterly flow aloft coupled with strong
daytime heating and lift both from orographic effects and a weak
vorticity maximum will support another day of thunderstorms across
the central Rockies. These thunderstorms should gradually move off
the higher terrain into the central High Plains, where a moderately
buoyant airmass will be in place. Around 30 to 35 kt of effective
bulk shear is expected over the region as well, which is strong
enough to support a mixed mode with supercells and multicell line
segments. Isolated large hail is possible with any supercells, while
severe wind gusts will be possible with both supercells and line
segments. The severe threat should persist into the early to mid
evening as this complex of storms moves eastward through the central
High Plains.

...Central OH Valley...
An expansive, slow-moving MCS, characterized by widespread showers
and sub-severe thunderstorms, is centered over central IL this
morning. This MCS has been supported overnight by a southwesterly
low-level jet that extends from the southern High Plains into the
Mid MS Valley. This low-level jet is forecast to wane throughout the
morning, with a subsequent decrease in coverage and intensity of the
showers and thunderstorms within the MCS. Even so, the vorticity
maximum associated with this system will gradually drift eastward,
likely supporting renewed thunderstorm development across the
middle/upper OH Valley as it interacts with a diurnally
destabilizing airmass. Lapse rates will be poor, but dewpoints in
the 70s will still support moderate buoyancy, particularly in areas
where cloud cover does not overly inhibit diurnal heating. This
currently appears most likely from far southeast IN into southern OH
and northern KY. Strong updrafts and high precipitable water will
support the potential for wet microbursts capable of producing
damaging gusts.

...Central Appalachians into the Carolinas and GA...
A very moist airmass, characterized by dewpoints in the low to mid
70s, is in place from the GA and Carolinas into the central
Appalachians. Strong heating is forecast to destabilize this airmass
by the early afternoon, resulting in a large reservoir of moderate
buoyancy. Thunderstorm development is anticipated within this
destabilized airmass across the higher terrain of the central
Appalachians as well as any area of low-level convergence across the
remainder of the region. Vertical shear will be weak, and limited
storm organization is anticipated. Even so, the moderate buoyancy
could still support updrafts/downdrafts strong enough to produce
occasional damaging gusts.

...Central Plains/Mid MO Valley into the Mid MS Valley...
Elevated thunderstorms are expected again this evening through
tonight, initiated by both an approaching cold front and warm-air
advection. Ample low-level moisture and moderate buoyancy will be in
place, but vertical shear will be marginal. Isolated strong to
severe storms are expected, but a predominantly elevated and
clustered storm mode should limit the overall severe potential.

..Mosier/Dean.. 08/15/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 15 16:37:04 2026

ACUS01 KWNS 151636
SWODY1
SPC AC 151635

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1135 AM CDT Sat Aug 15 2026

Valid 151630Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE/CENTRAL HIGH PLAINS AND MIDDLE OHIO VALLEY...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail are
possible from late afternoon into the evening across the central
High Plains. Severe wind gusts may also occur this afternoon through
early evening across parts of the Ohio Valley and Southeast.

...Front Range/Central High Plains...
Modestly strong southwesterly flow aloft coupled with strong
daytime heating, low-level upslope flow, and orographic lift will
support another day of thunderstorms regionally. These thunderstorms
should gradually move off the higher terrain into the central High
Plains later this afternoon, where a moderately
buoyant airmass will be in place. Around 30-35 kt of effective
bulk shear is expected over the region, which will support a mixed
mode with supercells and multicell line segments. Isolated large
hail is possible with any supercells, while severe wind gusts will
be possible with both supercells and line segments. The severe
threat should persist into the evening as this complex of storms
moves eastward through the central High Plains including
west/southwest Kansas.

...Midwest/Middle Ohio Valley...
Thunderstorms have generally weakened since the overnight, although
scattered showers/some thunderstorms and plentiful cloud cover
continue in areas progressively north of the Ohio River. An MCV is
readily apparent in observational data as it continues to move into
northwest Indiana, with an enhanced belt (40+ kt) of westerly winds
associated with the MCV per regional WSR-88D VWP data.

As clouds thin/abate, a gradual increase in renewed thunderstorm
coverage and intensity is expected later this afternoon. Mid-level
lapse rates will be poor, but dewpoints in the 70s F will support
moderate buoyancy, particularly in areas where cloud cover does not
overly inhibit diurnal heating, which will tend to generally be
southward toward the Ohio River. Strong updrafts and high
precipitable water will support the potential for wet microbursts
capable of producing damaging gusts, and some enhancement to the
low-level winds could also yield a brief tornado.

...Central Appalachians/Carolinas/Georgia...
A very moist airmass, characterized by dewpoints in the low to mid
70s, is in place regionally. Strong heating will destabilize the
airmass by the early afternoon, resulting in a large reservoir of
moderate buoyancy. Thunderstorm development is anticipated within
this destabilized airmass across the higher terrain of the central
Appalachians as well as any area of low-level convergence across the
remainder of the region. Vertical shear will be weak, and limited
storm organization is anticipated. Even so, the moderate buoyancy
could still support updrafts/downdrafts strong enough to produce
occasional damaging gusts.

...Central Plains/Mid Missouri Valley to Mid Mississippi Valley...
Elevated thunderstorms are expected again tonight, initiated by both
an approaching cold front and warm-air advection. Ample low-level
moisture and moderate buoyancy will be in place, but vertical shear
will be marginal. Isolated strong to severe storms are expected, but
a predominantly elevated and clustered storm mode should limit the
overall severe potential.

..Guyer/Chalmers.. 08/15/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 15 19:43:10 2026

ACUS01 KWNS 151942
SWODY1
SPC AC 151941

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0241 PM CDT Sat Aug 15 2026

Valid 152000Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
OHIO VALLEY AND PARTS OF THE CENTRAL HIGH PLAINS...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail remain
possible from late afternoon into the evening across the central
High Plains. Severe wind gusts may also still occur this afternoon
through early evening across parts of the Ohio Valley and Southeast.

...20Z Update...
The previous forecast (see below) remains generally on track, with
only minor changes made to the 20Z Day 1 Convective Outlook Update
to reflect the latest observations and latest guidance consensus.
There were considerations to add a Category 1/Marginal Risk for
severe wind/hail over portions of the Pacific Northwest into the
northern Rockies given appreciable cool temperatures aloft
overspreading a heated boundary layer. Nonetheless, vertical wind
shear should remain quite weak. Therefore, while a 50+ kt gust or
instance of 1+ inch hail may occur with any of the stronger storms,
the severe threat should be very sparse, precluding severe
probabilities this outlook.

..Squitieri.. 08/15/2026

.PREV DISCUSSION... /ISSUED 1135 AM CDT Sat Aug 15 2026/

...Front Range/Central High Plains...
Modestly strong southwesterly flow aloft coupled with strong
daytime heating, low-level upslope flow, and orographic lift will
support another day of thunderstorms regionally. These thunderstorms
should gradually move off the higher terrain into the central High
Plains later this afternoon, where a moderately
buoyant airmass will be in place. Around 30-35 kt of effective
bulk shear is expected over the region, which will support a mixed
mode with supercells and multicell line segments. Isolated large
hail is possible with any supercells, while severe wind gusts will
be possible with both supercells and line segments. The severe
threat should persist into the evening as this complex of storms
moves eastward through the central High Plains including
west/southwest Kansas.

...Midwest/Middle Ohio Valley...
Thunderstorms have generally weakened since the overnight, although
scattered showers/some thunderstorms and plentiful cloud cover
continue in areas progressively north of the Ohio River. An MCV is
readily apparent in observational data as it continues to move into
northwest Indiana, with an enhanced belt (40+ kt) of westerly winds
associated with the MCV per regional WSR-88D VWP data.

As clouds thin/abate, a gradual increase in renewed thunderstorm
coverage and intensity is expected later this afternoon. Mid-level
lapse rates will be poor, but dewpoints in the 70s F will support
moderate buoyancy, particularly in areas where cloud cover does not
overly inhibit diurnal heating, which will tend to generally be
southward toward the Ohio River. Strong updrafts and high
precipitable water will support the potential for wet microbursts
capable of producing damaging gusts, and some enhancement to the
low-level winds could also yield a brief tornado.

...Central Appalachians/Carolinas/Georgia...
A very moist airmass, characterized by dewpoints in the low to mid
70s, is in place regionally. Strong heating will destabilize the
airmass by the early afternoon, resulting in a large reservoir of
moderate buoyancy. Thunderstorm development is anticipated within
this destabilized airmass across the higher terrain of the central
Appalachians as well as any area of low-level convergence across the
remainder of the region. Vertical shear will be weak, and limited
storm organization is anticipated. Even so, the moderate buoyancy
could still support updrafts/downdrafts strong enough to produce
occasional damaging gusts.

...Central Plains/Mid Missouri Valley to Mid Mississippi Valley...
Elevated thunderstorms are expected again tonight, initiated by both
an approaching cold front and warm-air advection. Ample low-level
moisture and moderate buoyancy will be in place, but vertical shear
will be marginal. Isolated strong to severe storms are expected, but
a predominantly elevated and clustered storm mode should limit the
overall severe potential.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Aug 16 00:53:12 2026

ACUS01 KWNS 160052
SWODY1
SPC AC 160051

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 PM CDT Sat Aug 15 2026

Valid 160100Z - 161200Z

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

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible this evening across parts of the central Plains. Isolated
severe wind gusts may also occur this evening into tonight across
parts of the lower Missouri and Ohio Valleys.

...Central Plains/Lower Missouri Valley...
A mid-level shortwave trough is evident on water vapor imagery over
eastern Colorado within west-southwesterly flow. Ahead of this
feature, a moist airmass is present across the central Plains.
Surface dewpoints in eastern Colorado and western Kansas are in the
60s F, and the RAP has MLCAPE in the 1500 to 3000 J/kg range. Along
the western edge of moderate instability, scattered thunderstorms
are ongoing from western Nebraska southward into the Oklahoma
Panhandle. In addition to moderate instability, RAP forecast
soundings early this evening downstream from the storms near Dodge
City and Hill City and have 0-6 km shear around 30 knots with 0-3 km
lapse rates near 7.5 C/km. The steep low to mid-level lapse rates
are evident on the Dodge City 00Z sounding. This environment should
support an isolated severe threat for several more hours this
evening as the storms move across the central Plains. Severe wind
gusts and hail will be the primary threats...see MCD 1992. During
the overnight period, a convective cluster or line segment is
forecast to move east-northeastward across northern Kansas and
southern Nebraska, potentially reaching far northwest Missouri late
in the period. Isolated severe gusts will be possible with these
storms.

...Ohio Valley...
A mid-level shortwave trough is evident on water vapor imagery over
the Ohio Valley within west-northwesterly flow. At the surface, a
moist axis is located from central Illinois southeastward into
eastern Kentucky, along which surface dewpoints are in the 70s F.
Near the moist axis, the RAP has MLCAPE in the 2500 to 3500 J/kg
range. To the east and northeast of the strongest instability,
scattered thunderstorms are currently ongoing ahead of the shortwave
trough in western Ohio and northern Kentucky. The Wilmington, Ohio
00Z sounding has 0-6 km shear around 30 knots with a surface
dewpoint in the mid 70s F, and precipitable water near 2.15 inches.
This moist and unstable environment should support a potential for
isolated severe wet downbursts with the stronger multicells early
this evening.

..Broyles.. 08/16/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Aug 16 05:58:06 2026

ACUS01 KWNS 160557
SWODY1
SPC AC 160556

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1256 AM CDT Sun Aug 16 2026

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY...CENTRAL APPALACHIANS...MID-ATLANTIC AND CENTRAL
HIGH PLAINS...

...SUMMARY...
Thunderstorms with severe wind gusts will be possible from this
afternoon into early evening over parts of the Ohio Valley and
Mid-Atlantic. Large hail and isolated severe wind gusts will also be
possible in parts of the central High Plains.

...Ohio Valley/Mid-Atlantic...
A mid-level shortwave trough, embedded in west-northwesterly flow,
will move through the Ohio Valley today. Ahead of the shortwave
trough, a moist airmass will be in place from the Ohio Valley
southeastward to the Mid-Atlantic Coast. Surface dewpoints along
this west-northwest to east-southeast corridor will be in the 70s F,
which will contribute to the development of moderate instability by
midday. At the surface, a cold front will advance eastward into the
Ohio Valley, as a pre-frontal trough moves into the central
Appalachians. These two features will focus convective development
during the day. A complex of storms appears likely to form over the
higher terrain in West Virginia, and move east-southeastward into
the lower elevations of Virginia and Maryland during the mid to late
afternoon.

RAP forecast soundings from West Virginia into the Virginia in the
late afternoon have 0-6 km shear in the 25 to 30 knot range. Some
directional shear is present in the low-levels and 0-3 km lapse
rates are steep approaching 7 C/km. This environment will support a
wind-damage threat with organized multicells. Isolated supercells
with severe gusts will also be possible. The threat may continue
into the early evening across parts of the Mid-Atlantic.

Further west into parts of the lower Ohio Valley, a very moist
airmass will also be in place. Surface dewpoints in the 70s F will
contribute to the development of moderate instability. Scattered
thunderstorms are expected to form along zones of low-level
convergence during the afternoon. Although large-scale ascent will
be weaker further west, the thermodynamic environment will be
sufficient for isolated severe gusts.

...Central High Plains...
At mid-levels, a ridge will move through the Intermountain West
today as flow remains westerly over much of the central U.S. As
surface temperatures warm, scattered thunderstorms will develop in
the foothills of the central Rockies. These storms will move
eastward into the lower elevations of eastern Colorado and western
Nebraska. RAP forecast soundings across the central High Plains by
late afternoon have moderate instability (MLCAPE around 2500 J/kg),
0-6 km shear near 35 knots and 700 to 500 mb lapse rates in the 7 to
7.5 C/km range. This should support a threat for large hail and
isolated severe gusts with rotating storms and organized line
segments. The threat will likely persist into the evening across
parts of the central High Plains.

..Broyles/Lyons.. 08/16/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Aug 16 12:44:38 2026

ACUS01 KWNS 161244
SWODY1
SPC AC 161242

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0742 AM CDT Sun Aug 16 2026

Valid 161300Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY...CENTRAL APPALACHIANS...MID-ATLANTIC...AND CENTRAL
HIGH PLAINS...

...SUMMARY...
Thunderstorms with damaging wind gusts will be possible from this
afternoon into early evening over parts of the Ohio Valley and
Mid-Atlantic. Large hail and isolated severe wind gusts will also be
possible in parts of the central High Plains.

...Lower MO Valley through the OH Valley into the Mid-Atlantic...
Satellite and regional radar imagery shows several vorticity maxima
embedded within the moderate westerly flow aloft that extends from
the central Plains across the OH Valley and into the Mid-Atlantic.
The strongest vorticity maximum is currently moving through
north-central KS and south-central NE, while more subtle maxima
exist across western IL, southwestern Lower MI/far northern IN, and
western PA. Each of these features will likely contribute to showers
and thunderstorms later today. The most consequential of these
storms will likely occur in tandem with the western IL and
southwestern Lower MI waves as they interact with a moist and
diurnally destabilized airmass from the middle OH Valley into the
Mid-Atlantic. Airmass destabilization appears likely by the early
afternoon, with renewed thunderstorm development anticipated from
southeast Lower MI into southern IN. Moderate vertical shear will be
in place, supporting a predominantly multicellular mode. Mid-level
winds may increase slightly throughout the afternoon, and a
supercell or two is possible over southern OH. A trend towards
clustering and the development of linear segments is anticipated
over time, with damaging gusts as the primary risk throughout the
day.

These storms will continue eastward across WV into Mid-Atlantic
during the late afternoon/early evening. Moderate buoyancy will
support storm persistence and the potential for continued damaging
gusts. Additional thunderstorm development is possible ahead of
these clusters in areas of low-level convergence during the
afternoon. Moderate vertical shear could support a few more
organized storms, with water-loaded downbursts as the primary severe
risk. A tornado or two is also possible, particularly across
northern VA where southerly surface winds could result in adequate
low-level hodograph curvature.

Farther west (across the Lower MO Valley), the well-defined
vorticity maximum currently over north-central KS/southern-central
NE is forecast to be east of the region by the late afternoon, but
airmass destabilization in its wake is uncertain. If the airmass can
recover, additional thunderstorms are likely along a cold front
moving into the region this evening. Strong buoyancy will support
robust updrafts, but modest vertical shear will keep storm
organization limited. If thunderstorms form, a few strong gusts are
possible across this region this evening.

...Northern/Central High Plains...
Scattered thunderstorm development in anticipated this afternoon
across the northern and central High Plains. Thunderstorms over the
northern High Plains will be supported by low-level convergence
along the western edge of the moist airmass over the Plains.
Moderate vertical shear could support a few supercells capable of
hail and strong gusts, but modest buoyancy should keep the overall
severe threat isolated.

Thunderstorm development farther south across the central High
Plains will result from a combination of moist low-level easterlies,
westerly flow aloft and orographic effects. Here, more cellular
development over the high terrain and immediate foothills could pose
a risk for large hail before transitioning towards more linear
structures with strong gusts as the primary severe risk.

..Mosier/Dean.. 08/16/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 17 13:16:20 2026

ACUS01 KWNS 171256
SWODY1
SPC AC 171254

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 AM CDT Mon Aug 17 2026

Valid 171300Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN AND CENTRAL PLAINS...AND THE SOUTHERN APPALACHIANS INTO
THE NORTH CAROLINA PIEDMONT...

...SUMMARY...
Thunderstorms with severe wind gusts and hail will be possible this
afternoon and evening across parts of the central and northern
Plains. Damaging gusts will also be possible in parts of the
southern Appalachians into the North Carolina Piedmont, Oklahoma and
Arkansas.

...Northern/Central Plains...
Modest height falls are expected across the northern Plains as
troughing over central Canada deepens. As it does, an associated
surface low will shift eastward and an attendant cold front will
push southward/southeastward across eastern MT, ND, and northwest
MN. The airmass preceding this front will be moist and strongly
unstable, with dewpoints likely in the upper 60s and MLCAPE over
2500 J/kg. Several different areas of initial development appear
possible, including along the front from eastern ND into
northwestern MN, in the vicinity of the pre-frontal trough over the
NE Panhandle vicinity, and south of the front across eastern MT.

Development across eastern ND/northwestern MN and the NE Panhandle
should progress southeastward into the corridor of greater buoyancy.
Even so, weak ascent and relatively warm mid-levels could limit both
overall storm coverage and updraft longevity. That being said,
vertical shear will be strong enough to support updraft organization
and supercell structures with any deep updrafts. Steep low-level
lapse rates and high cloud bases suggest strong gusts are the
primary severe risk, but some isolated large hail is also possible.
Widely scattered nature of the storms casts doubt regarding upscale
growth into a coherent MCS, but several separate bowing clusters
appear probable.

Thunderstorm coverage is expected to remain isolated from central
into eastern MT as well, with modest ascent attendant to a shortwave
trough progressing through the northern periphery of the western
CONUS ridging acting as the primary impetus for initiation.
Predominantly outflow-dominant storm structures are anticipated,
with strong gusts as the primary severe risk through the evening.
Convective evolution is uncertain, but these storms could continue
eastward through SD and NE overnight, reintensifying as they
interact with the stronger buoyancy expected to be in place. In
addition to strong gusts, large hail would be possible with these
storms if reintensification occurs.

...Central/Southern Appalachians into the Piedmont...
Early-morning satellite and regional radar imagery show a decaying
MCS progressing across central KY, well ahead of weak cold front
that extends from far northwest OH southwestward through far
southeast MO and northern AR. This MCS is forecast to continue
eastward throughout the day, moving through the central Appalachians
and eventually central VA. The airmass over this region is very
moist, with recent surface analysis sampling upper 60s dewpoints
over the higher terrain and low to mid 70s farther east from central
VA into the Carolina Piedmont.

General expectation is for renewed thunderstorm development along
the southern flank of the MCS, likely from far southeast KY into
Middle TN. Some reintensification is also possible farther north
over WV and downstream in northern/central VA, but buoyancy will be
lower than farther south, suggesting predominantly muted/transient
updrafts. Currently, the highest storm coverage appears most likely
across far western WV, eastern TN, and western NC. Vertical shear
will be weak, but moderate/strong buoyancy and steep low-level lapse
rates will still support the potential for damaging gusts. These
strong outflows could promote the development of several
forward-propagating line segments, where updrafts/downdrafts along
the outflows could result in additional damaging gusts.

...Oklahoma/Arkansas...
An MCS continues to progress eastward into northeast OK this
morning, with a well-defined MCV noted in radar imagery back across
far northwest OK. An associated outflow boundary currently arcs from
the leading edge of the MCS in Osage County back southwestward
through southwest OK. This MCS is forecast to weaken as it
progresses eastward this morning, with weakening outflow also moving southeastward. A composite outflow/cold front will likely extend
from southern OK into central AR this afternoon. Low-level
convergence near this boundary will likely result in widely
scattered thunderstorms by the late afternoon. Vertical shear will
be weak, limiting storm organization. However, moderate instability,
high cloud bases, and steep low-level lapse rates will still support
the potential for isolated severe downbursts.

..Mosier/Dean.. 08/17/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 17 13:41:02 2026

ACUS01 KWNS 162002
SWODY1
SPC AC 162000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sun Aug 16 2026

Valid 162000Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITHIN THE FRONT
RANGE AND PARTS OF THE CENTRAL/NORTHERN HIGH PLAINS...AND PORTIONS
OF THE OHIO VALLEY INTO THE MID-ATLANTIC...

...SUMMARY...
Thunderstorms with damaging wind gusts will be possible this
afternoon and early evening over parts of the Ohio Valley and
Mid-Atlantic. Large hail and isolated severe wind gusts will also be
possible across the Front Range and central/northern High Plains.

...20Z Update...
Ongoing convection within the Upper Ohio Valley vicinity continues
eastward this afternoon. Behind this convection, buoyancy has been
reduced. Wind probabilities have also been reduced, though isolated
strong to marginally severe storms are possible where some airmass
recovery has occurred. Elsewhere, the forecast remains on track with
only minor changes to the general thunderstorm forecast.

..Wendt.. 08/16/2026

.PREV DISCUSSION... /ISSUED 1144 AM CDT Sun Aug 16 2026/

...Upper Ohio Valley to Appalachians and Mid-Atlantic/Carolinas...
An MCV persists at midday across far southeast Michigan and northern
Ohio, with some recent uptick in convection ahead of it across
northern Ohio. Reference Mesoscale Discussion 1195 for short-term
details regarding a further increase in severe potential through early/mid-afternoon within this regional corridor.

While storms have weakened, showers/cloud cover remain prevalent
near/east of the Appalachians at midday across the Mid-Atlantic
region. This will tend to limit/delay destabilization in many areas
(especially with north-northeastward extent). That said, air mass recovery/advection is expected from the west, with ample upstream
clearing per visible satellite imagery across the Cumberland Plateau
into parts of the Allegheny Plateau. Pending the timing/location of destabilization, some terrain/lee trough-related development may
diurnally occur, although the most prevalent/more certain scenario
may be for potentially severe storms to spread into the region this
evening. Damaging winds will be the most common hazard regionally,
although a tornado could occur, attributable to MCV-enhanced flow
and/or with any storms interacting with the effective warm front
across the Mid-Atlantic region.

...Middle Mississippi Valley including Missouri/Illinois...
An MCV over the Nebraska/Kansas/Iowa/Missouri border vicinity late
this morning will likely continue generally eastward, while probably
largely maintaining its related belt of enhanced mid-level flow as
observed from regional WSR-88D VWP data. A key downstream
uncertainty is the midday persistence of weak convection across
eastern Missouri into west/southwest Illinois, and that mid-level
lapse rates are rather poor to its north aside from some lingering
cloud cover.

More certain/greater destabilization may occur to the west across
Missouri, with the southeastward-advancing front being a focus for
renewed thunderstorm development later this afternoon and evening
amidst moderate/locally strong buoyancy. Deep-layer shear will tend
to be limited to around 30 kt in most areas, although somewhat
stronger MCV-related winds aloft may support upwards of 35-40 kt
effective shear for any storms across northern Missouri into west-central/southwest Illinois. Bouts of damaging winds are the
most likely hazard regionally.

...Front Range/Raton Mesa and northern/central High Plains...
A relatively similar pattern/scenario as prior few days will
continue regionally, except a somewhat more northward-extent of the
severe risk (such as Black Hills vicinity) and a trend toward a more
northerly component to the flow aloft across the north-central High
Plains. At least widely scattered thunderstorm development is
expected into mid/late afternoon spanning the Front Range/Raton Mesa
vicinity northward across eastern Wyoming/southeast Montana and the
Black Hills vicinity. In the presence of upwards of 1500-2000 J/kg
MLCAPE, moderate vertical shear (30-40 kt) could support a few
supercells capable of severe hail. Isolated damaging winds will be
possible. This includes the most probable zone for gradual
upscale-growing linear cluster(s) across the south-central High
Plains/Raton Mesa vicinity including southeast Colorado/northeast
New Mexico toward the Oklahoma/Texas Panhandles and far southwest
Kansas. A couple of southeastward-moving thunderstorm clusters
capable of wind/damage may also emerge this evening out of the Black
Hills vicinity/western Nebraska.

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 17 13:46:10 2026

ACUS01 KWNS 161645
SWODY1
SPC AC 161644

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1144 AM CDT Sun Aug 16 2026

Valid 161630Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT
RANGE AND CENTRAL/NORTHERN HIGH PLAINS AND OHIO
VALLEY/MID-ATLANTIC...

...SUMMARY...
Thunderstorms with damaging wind gusts will be possible this
afternoon and early evening over parts of the Ohio Valley and
Mid-Atlantic. Large hail and isolated severe wind gusts will also be
possible across the Front Range and central/northern High Plains.

...Upper Ohio Valley to Appalachians and Mid-Atlantic/Carolinas...
An MCV persists at midday across far southeast Michigan and northern
Ohio, with some recent uptick in convection ahead of it across
northern Ohio. Reference Mesoscale Discussion 1195 for short-term
details regarding a further increase in severe potential through early/mid-afternoon within this regional corridor.

While storms have weakened, showers/cloud cover remain prevalent
near/east of the Appalachians at midday across the Mid-Atlantic
region. This will tend to limit/delay destabilization in many areas
(especially with north-northeastward extent). That said, air mass recovery/advection is expected from the west, with ample upstream
clearing per visible satellite imagery across the Cumberland Plateau
into parts of the Allegheny Plateau. Pending the timing/location of destabilization, some terrain/lee trough-related development may
diurnally occur, although the most prevalent/more certain scenario
may be for potentially severe storms to spread into the region this
evening. Damaging winds will be the most common hazard regionally,
although a tornado could occur, attributable to MCV-enhanced flow
and/or with any storms interacting with the effective warm front
across the Mid-Atlantic region.

...Middle Mississippi Valley including Missouri/Illinois...
An MCV over the Nebraska/Kansas/Iowa/Missouri border vicinity late
this morning will likely continue generally eastward, while probably
largely maintaining its related belt of enhanced mid-level flow as
observed from regional WSR-88D VWP data. A key downstream
uncertainty is the midday persistence of weak convection across
eastern Missouri into west/southwest Illinois, and that mid-level
lapse rates are rather poor to its north aside from some lingering
cloud cover.

More certain/greater destabilization may occur to the west across
Missouri, with the southeastward-advancing front being a focus for
renewed thunderstorm development later this afternoon and evening
amidst moderate/locally strong buoyancy. Deep-layer shear will tend
to be limited to around 30 kt in most areas, although somewhat
stronger MCV-related winds aloft may support upwards of 35-40 kt
effective shear for any storms across northern Missouri into west-central/southwest Illinois. Bouts of damaging winds are the
most likely hazard regionally.

...Front Range/Raton Mesa and northern/central High Plains...
A relatively similar pattern/scenario as prior few days will
continue regionally, except a somewhat more northward-extent of the
severe risk (such as Black Hills vicinity) and a trend toward a more
northerly component to the flow aloft across the north-central High
Plains. At least widely scattered thunderstorm development is
expected into mid/late afternoon spanning the Front Range/Raton Mesa
vicinity northward across eastern Wyoming/southeast Montana and the
Black Hills vicinity. In the presence of upwards of 1500-2000 J/kg
MLCAPE, moderate vertical shear (30-40 kt) could support a few
supercells capable of severe hail. Isolated damaging winds will be
possible. This includes the most probable zone for gradual
upscale-growing linear cluster(s) across the south-central High
Plains/Raton Mesa vicinity including southeast Colorado/northeast
New Mexico toward the Oklahoma/Texas Panhandles and far southwest
Kansas. A couple of southeastward-moving thunderstorm clusters
capable of wind/damage may also emerge this evening out of the Black
Hills vicinity/western Nebraska.

..Guyer/Chalmers.. 08/16/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 17 14:01:04 2026

ACUS01 KWNS 170101
SWODY1
SPC AC 170059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Sun Aug 16 2026

Valid 170100Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
OHIO VALLEY INTO THE MID-ATLANTIC...AND ACROSS THE CENTRAL HIGH
PLAINS...

...SUMMARY...
Thunderstorms with severe wind gusts will be possible this evening
from parts of the Ohio Valley into the Mid-Atlantic. Thunderstorms
with isolated severe gusts and hail will be possible in parts of the
High Plains.

...Ohio Valley/Central Appalachians/Mid-Atlantic...
On water vapor imagery, a mid-level shortwave trough is evident in
the Ohio Valley within west-northwest flow. This feature is moving
into the central Appalachians where surface dewpoints are mostly in
the upper 60s and lower 70s F. Moderate instability is analyzed by
the RAP across much of the region. Low-level convergence is
maximized along a pre-frontal trough in the Mid-Atlantic where
isolated strong thunderstorms are ongoing. A secondary max of
convergence is located from central Kentucky into western West
Virginia, along which an organized line segment is ongoing. These
storm clusters are expected to persist for a few more hours.

Ahead of the ongoing storms, the WSR-88D VWPs at Jackson, Kentucky
and Blacksburg, Virginia have 0-6 km shear of about 30 knots with
nearly unidirectional west to northwesterly winds in the low to
mid-levels. The 00Z sounding at Roanoke, Virginia has MLCAPE around
2200 J/kg, with 0-3 km lapse rates near 7.5 C/km. This environment
will support a potential for severe wind gusts with the stronger
cells this evening.

Further west into the mid Mississippi Valley, strong thunderstorms
are currently ongoing along a gradient of moderate to strong
instability, analyzed by the RAP in eastern Missouri. The unstable thermodynamic environment along with sufficient deep-layer shear
will support an isolated wind-damage threat for a few more hours
this evening.

...High Plains...
Mid-level flow is west-northwesterly over the High Plains this
evening. According to water vapor imagery, a shortwave trough is
located over eastern Colorado. Ahead of this feature, a moist
airmass is present over much of the central Plains, where surface
dewpoints are mostly in the 60s F. An axis of moderate instability
is analyzed by the RAP from the northern Texas Panhandle northward
into northwestern Nebraska. Along and near this axis, multiple small
clusters of strong to severe storms are ongoing. The strongest
deep-layer shear is analyzed by the RAP from east-central Colorado
northward into western Nebraska, where 0-6 km shear is estimated to
be in the 30 to 40 knot range. Within this zone, low to mid-level
lapse rates are estimated to be around 7 C/km. This environment will
be sufficient for an isolated severe threat this evening. Severe
wind gusts and hail will be the primary threats.

..Broyles.. 08/17/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 17 14:20:52 2026

ACUS01 KWNS 170604
SWODY1
SPC AC 170602

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0102 AM CDT Mon Aug 17 2026

Valid 171200Z - 181200Z

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

...SUMMARY...
Thunderstorms with severe wind gusts and hail will be possible this
afternoon and evening across parts of the central and northern
Plains. Severe gusts will also be possible in parts of the southern Appalachians. Isolated severe gusts may occur in parts of Oklahoma
and Montana.

...Central and Northern Plains...
At mid-levels, a subtle shortwave trough will move across the
northern Plains today, within west-northwesterly flow. Ahead of this
feature, a broad corridor of low-level moisture will be in place
over the central and northern Plains. A moist axis, with surface
dewpoints in the upper 60s and lower 70s F, will setup from
northwest Kansas north-northeastward into central Nebraska and
eastern South Dakota. Along and near the moist axis, moderate to
strong instability will develop by midday with MLCAPE likely
increasing into the 2000 to 3000 J/kg range. At the surface, a cold
front will move southeastward across the Dakotas during the day.
Low-level convergence will become maximized ahead of the front
across central Nebraska and southeast South Dakota. This will lead
to scattered convective initiation, with thunderstorms forming and
moving southeastward into the stronger instability during the late
afternoon and early evening.

RAP forecast soundings near the instability axis at 00Z from
northeastern Nebraska into eastern South Dakota have 0-6 km shear
near 40 knots with low to mid-level lapse rates in the 7 to 7.5 C/km
range. This will support supercell development and isolated large
hail production in areas that have the best overall environment.
However, a mixed mode is expected. Supercells and multicells will be
capable of severe wind gusts. The severe threat will likely continue
into the mid evening, as a somewhat large convective cluster moves southeastward into the mid Missouri and upper Mississippi Valleys.

...Southern Appalachians...
A mid-level shortwave trough will move east-southeastward across the
Ohio and Tennessee Valleys today, reaching the southern Appalachians
by early evening. Ahead of this feature, a moist and unstable
airmass will be in place. Surface dewpoints in the 70s F will lead
to the development of moderate to strong instability by midday. At
the surface, a cold front will advance southeastward into the
southern Appalachians. Low-level convergence along the front, along
with topographic forcing, will result in scattered thunderstorm
development in the afternoon. These storms are expected to move east-southeastward across the higher terrain of the southern
Appalachians and into the lower elevations by early evening. The
very moist and unstable air, along with 0-6 km shear in the 20 to 30
knot range will support a wind-damage threat. Severe gusts will be
most likely with short organized line segments. The severe threat
could persist into the early evening.

...Southern Plains...
At the surface, a quasi-stationary front will remain in place across
southern and western Oklahoma today. Within the post-frontal air,
surface dewpoints will be from the mid 60s to the mid 70s F. As
surface temperatures warm, moderate to strong instability will
develop along and near the most axis. The instability, combined with
sufficient deep-layer shear and 0-3 km lapse exceeding 8 C/km will
be favorable for isolated severe wet downbursts.

...Northern High Plains...
West-northwest mid-level flow will be in place in the northern High
Plains over the top of a post-frontal airmass. Surface dewpoints in
parts of central and eastern Montana will be around 50 F. MLCAPE
will increase into the 500 to 1000 J/kg range over parts of the
northern High Plains. As temperatures warm during the day,
thunderstorms are expected to form in the higher terrain of central
Montana, with isolated cells moving eastward across the upper
Missouri Valley. Very steep low to mid-level lapse rates could
support an isolated potential for severe wind gusts during the late
afternoon and early evening.

..Broyles/Thornton.. 08/17/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 17 16:58:36 2026

ACUS01 KWNS 171654
SWODY1
SPC AC 171652

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1152 AM CDT Mon Aug 17 2026

Valid 171630Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTH-CENTRAL PLAINS/UPPER MIDWEST AND SOUTHERN APPALACHIANS...

...SUMMARY...
Thunderstorms with severe wind gusts and large hail are expected
this afternoon and evening across parts of the central and northern
Plains. Damaging gusts will also be possible in parts of the
southern Appalachians to the North Carolina Piedmont, and possibly
across portions of the Mid-South and southern Plains.

...Northern/Central Plains...
Weak height falls are expected regionally with a seasonally
prominent strengthening of northwesterly flow aloft. A surface low
will shift eastward and an attendant cold front will push southward/southeastward across eastern Montana, North Dakota and
toward west/northwest Minnesota. The airmass preceding this front
will be moist and strongly unstable, with dewpoints in the upper 60s
and MLCAPE over 2500 J/kg. Multiple areas of initial development are
expected, including along the front from eastern Dakotas into
western Minnesota, and in the vicinity of the pre-frontal trough
and/or front over the NE Panhandle vicinity, southern South Dakota,
and southeast Montana/far eastern Wyoming.

Mid/Late-afternoon storm development in each of these areas will
progress into zones of greater buoyancy by evening. Some initial
supercells capable of large hail are expected, especially given the
strength of the deep-layer wind profiles, while steep low-level
lapse rates and high cloud bases will support strong wind gust
potential, especially with the possibility that storms may
cluster/organize this evening across Nebraska/southern South Dakota,
and possibly across Siouxland and western Minnesota.

...Central/Southern Appalachians into the Piedmont...
Within a very moist airmass, renewed thunderstorm development is
expected along the southern flank of a remnant thunderstorm cluster
and in vicinity of the higher terrain/mountains this afternoon.
Vertical shear will not be overly strong, but moderate/strong
buoyancy and steep low-level lapse rates will still support the
potential for damaging wind gusts. These strong outflows could
promote the development of several
forward-propagating/southeast-moving line segments with a persistent
potential for wind damage, at least through early evening.

...Oklahoma/Arkansas to Mid-South...
Aided by an MCV, a small cluster of storms with a morning history of
occasional severe-caliber winds continues at midday across northwest
Arkansas. For additional short-term details, see Mesoscale
Discussion 2010. While not certain or perhaps likely, a general eastward-persistence of this cluster could occur. Additional
isolated storm development may occur regionally later this afternoon
along the remnant outflow and/or front, with steep low-level lapse
rates and ample buoyancy supportive of damaging downburst potential
through around sunset.

..Guyer/Chalmers.. 08/17/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Mon Aug 17 20:07:14 2026

ACUS01 KWNS 172005
SWODY1
SPC AC 172003

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0303 PM CDT Mon Aug 17 2026

Valid 172000Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITHIN PARTS OF
THE NORTH-CENTRAL PLAINS/UPPER MIDWEST...AND SOUTHERN
APPALACHIANS...

...SUMMARY...
Thunderstorms with severe wind gusts and large hail are expected
this afternoon and evening across parts of the central and northern
Plains. Damaging gusts will also be possible in parts of the
southern Appalachians to the North Carolina Piedmont, and possibly
across portions of the Mid-South and southern Plains.

...20Z Update...
Given the earlier than expected development within western South
Dakota/eastern Wyoming, the Slight Risk has been expanded
northwestward. See MD 2012 for additional information. One or more
organized clusters may eventually develop out of this activity as
the low-level jet increases into northern Nebraska/southern South
Dakota. Confidence on where a greater corridor of wind risk exists
is still too low for a categorical upgrade. Elsewhere, the forecast
remains on track.

..Wendt.. 08/17/2026

.PREV DISCUSSION... /ISSUED 1152 AM CDT Mon Aug 17 2026/

...Northern/Central Plains...
Weak height falls are expected regionally with a seasonally
prominent strengthening of northwesterly flow aloft. A surface low
will shift eastward and an attendant cold front will push southward/southeastward across eastern Montana, North Dakota and
toward west/northwest Minnesota. The airmass preceding this front
will be moist and strongly unstable, with dewpoints in the upper 60s
and MLCAPE over 2500 J/kg. Multiple areas of initial development are
expected, including along the front from eastern Dakotas into
western Minnesota, and in the vicinity of the pre-frontal trough
and/or front over the NE Panhandle vicinity, southern South Dakota,
and southeast Montana/far eastern Wyoming.

Mid/Late-afternoon storm development in each of these areas will
progress into zones of greater buoyancy by evening. Some initial
supercells capable of large hail are expected, especially given the
strength of the deep-layer wind profiles, while steep low-level
lapse rates and high cloud bases will support strong wind gust
potential, especially with the possibility that storms may
cluster/organize this evening across Nebraska/southern South Dakota,
and possibly across Siouxland and western Minnesota.

...Central/Southern Appalachians into the Piedmont...
Within a very moist airmass, renewed thunderstorm development is
expected along the southern flank of a remnant thunderstorm cluster
and in vicinity of the higher terrain/mountains this afternoon.
Vertical shear will not be overly strong, but moderate/strong
buoyancy and steep low-level lapse rates will still support the
potential for damaging wind gusts. These strong outflows could
promote the development of several
forward-propagating/southeast-moving line segments with a persistent
potential for wind damage, at least through early evening.

...Oklahoma/Arkansas to Mid-South...
Aided by an MCV, a small cluster of storms with a morning history of
occasional severe-caliber winds continues at midday across northwest
Arkansas. For additional short-term details, see Mesoscale
Discussion 2010. While not certain or perhaps likely, a general eastward-persistence of this cluster could occur. Additional
isolated storm development may occur regionally later this afternoon
along the remnant outflow and/or front, with steep low-level lapse
rates and ample buoyancy supportive of damaging downburst potential
through around sunset.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Aug 18 01:01:54 2026

ACUS01 KWNS 180101
SWODY1
SPC AC 180059

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Mon Aug 17 2026

Valid 180100Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL AND NORTHERN PLAINS...AND FROM NORTHEASTERN ALABAMA INTO
WESTERN NORTH CAROLINA...

...SUMMARY...
Thunderstorms with severe wind gusts and large hail are expected
this evening across parts of the central and northern Plains.
Isolated severe gusts will also be possible from parts of the
northern Gulf Coast States into the southern Appalachians and
Carolinas.

...Central and Northern Plains...
The latest water vapor imagery shows west-northwesterly flow over
much of the northern U.S., with a low-amplitude shortwave trough
moving through the flow in the northern Plains. At the surface, a
cold front is advancing southeastward through the Dakotas. Ahead of
the front, surface dewpoints are in the 60s F. The RAP has an axis
of moderate to strong instability located from central Nebraska
northeastward into eastern South Dakota, along which MLCAPE is
estimated in the 2500 to 3500 J/kg range. Isolated thunderstorms are
ongoing near the instability axis with scattered storms ongoing to
the west of the instability max in western Nebraska and southwestern
South Dakota.

These storms are located along the eastern edge of an elevated mixed
layer extending eastward from the central Rockies. Near the storms,
the RAP is estimating 700-500 mb lapse rates in the 7.5 to 8.5 C/km
range. In addition, the North Platte WSR-88D VWP has 0-6 km shear
near 50 knots with significant directional shear evident in the
lowest 3 km above ground level. This environment will support
supercells with large hail and severe wind gusts this evening. The
more intense storms could produce hailstones exceeding 2 inches in
diameter. Short-term model forecast suggest that the storms will
continue to move east-southeastward toward the instability axis this
evening, remaining relatively discrete. However, a transition to a
broken line segment should eventually occur, which would result in a
greater wind-damage threat. A few severe gusts above 75 mph will be
possible. The severe threat should persist into the mid to late
evening...See MCD 2019.

...Northern Gulf Coast States/Southern Appalachians/Carolinas...
The latest surface analysis shows a distinct outflow boundary from
northern Alabama eastward into the western Carolinas. Strong to
severe thunderstorms are ongoing near the outflow boundary. To the
south of the boundary, surface dewpoints are in the 70s F and the
RAP is estimating MLCAPE in the 2000 to 3500 J/kg range. Within the
most unstable air, RAP forecast soundings early this evening have
0-3 km lapse rate in the 7.5 to 8 C/km range, with precipitation
water above 2 inches. In addition, the WSR-88D VWP in northeast
Alabama has 0-6 km shear in the 20 to 25 knot range. This
environment will support a potential for severe wet downbursts for a
couple more hours this evening.

..Broyles.. 08/18/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Aug 18 05:58:54 2026

ACUS01 KWNS 180558
SWODY1
SPC AC 180556

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1256 AM CDT Tue Aug 18 2026

Valid 181200Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS AND LOWER MISSOURI VALLEY...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible this afternoon and evening from the central Plains into the
lower Missouri Valley. Isolated severe gusts and hail will also be
possible from the Northern High Plains eastward into the Midwest and
southern Great Lakes.

...Central and Northern Plains...
At mid-levels, a broad cyclonic flow pattern will be in place over
the northern U.S. A shortwave trough will move across the central
and northern Plains. At the surface, a cold front will advance
southward into Nebraska by afternoon. To the south of the front, an
outflow boundary from morning convection will move southward into
northern Kansas. A moist airmass will exist between the two
boundaries with surface dewpoints in the upper 60s to lower 70s F.
Within the moist air, moderate to strong instability will develop by
afternoon. The outflow boundary will be a focus for convective
initiation during the day, while additional storms are expected to
develop further west across the central High Plains in the late
afternoon. Increasing convective coverage during the early evening
should result in the development of a line segment.

RAP forecast soundings at 00Z from Salina to Kansas City have MLCAPE
in the 1500 to 2500 J/kg range with 0-6 km shear around 40 knots.
700-500 mb lapse rates are forecast to be in the 7 to 8 C/km range.
This environment will support supercells with isolated large hail.
The large hail threat will extend west-northwestward into southwest
Nebraska during the late afternoon where mid-level lapse rates will
be steeper and cells will likely remain discrete. The greatest
wind-damage potential is forecast from northern and eastern Kansas
into far western Missouri, where the development of an organized
bowing line segment will be possible in the early evening. Wind
gusts above 75 mph will be possible along the path of any intense
line segment. The severe threat may impact parts of lower Missouri
Valley and Ozarks by mid to late evening.

...Midwest/Great Lakes...
A mid-level shortwave trough will move across the north-central U.S.
today, as a cold front advances southeastward across the Midwest and
Great Lakes. To the south of the front, surface dewpoints in the 60s
F will contribute to moderate instability along an west-northwest-to-east-northeast axis from the mid Mississippi
Valley into the southern Great Lakes. Isolated to scattered
thunderstorms appear likely to form along and south of the front in
the late afternoon and early evening. MLCAPE in the 1000 to 2000
J/kg range, 0-6 km shear around 40 knots and precipitable water in
the 1.7 to 1.9 inch range will be favorable for isolated severe
storms capable of severe wet downbursts.

...Northern High Plains...
Northwesterly mid-level flow will be in place today from the
Northern Rockies into the Northern High Plains. At the surface,
dewpoints along the moist axis from northeastern Wyoming into
central Montana will be around 50 F. As surface temperatures warm
during the day, MLCAPE is expected to increase to around 1000 J/kg
in parts of the northern High Plains. Thunderstorms are expected to
form in the higher terrain in the afternoon, moving
east-southeastward into the lower elevations. Due to the instability
and steep low to mid-level lapse rates, isolated severe wind gusts
will be possible with the stronger cells.

..Broyles/Jirak.. 08/18/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Aug 18 12:49:24 2026

ACUS01 KWNS 181249
SWODY1
SPC AC 181247

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0747 AM CDT Tue Aug 18 2026

Valid 181300Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
KANSAS INTO CENTRAL MISSOURI...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible this afternoon and evening from the central Plains into the
lower Missouri Valley. Isolated severe gusts and hail will also be
possible from the Northern Rockies into the central High Plains, and
eastward into the Midwest and southern Lower Michigan. Damaging
gusts could also occur across parts of Mississippi and Alabama.

...Central Plains into Lower MO Valley...
Warm-air advection showers and thunderstorms are currently ongoing
across south-central/southeast NE. This activity is likely
reinforcing an outflow boundary from an earlier MCS that extends
from northwest KS into the NE/KS/MO border vicinity. These showers
and thunderstorms are expected to continue southeastward over the
next few hours, while gradually diminishing in coverage and
intensity. How this outflow modifies will influence the thunderstorm
potential across northern KS this afternoon. If the boundary does
not wash out, there could be a region of notable convergence that
develops across in the northwestern/north-central KS between the
outflow (reinforced by an approaching cold front) and a heat-driven
surface low that develops across western KS. Even with this
potential convergence, convective initiation is uncertain. Most
guidance maintains warm low/mid level temperatures, with the
resultant capping suppressing any thunderstorm development. Steep
lapse rates, moderate deep-layer vertical shear, and strong buoyancy
are expected north of the boundary, and there is a conditional risk
for large to very large hail and strong downdrafts if any updrafts
can mature.

A more certain scenario is expected farther east across eastern KS,
where evening thunderstorm development is anticipated as the
low-level jet increases. Steep lapse rates and moderate vertical
shear support the potential for thunderstorms capable of large hail
during the initially more cellular mode. These storms will likely
cluster quickly, with a trend towards upscale growth into a
forward-propagating MCS which then moves into MO. Damaging gusts
will become the primary risk once this occurs.

...Northern Rockies through the Central High Plains...
A shortwave trough is forecast to progress southeastward from
British Columbia/Alberta into the northern Rockies. Thunderstorm
development is anticipated across the northern Rockies as this wave
interacts with the destabilized and buoyant airmass across the
region. Moderate westerly flow will accompany this wave as well,
supporting the potential for more organized storm structures and the development of several line segments. These widely scattered
thunderstorms are forecast to progress eastward/southeastward this afternoon/evening, with additional development possible from WY into
the central High Plains. The moderate westerly flow aloft, high
storm bases, and steep low-level lapse rates support the potential
for strong to severe wind gusts as these storms progress eastward/southeastward.

...Southern WI/northern IL into Lower MI...
Low-level moisture is expected to increase across the Midwest ahead
of an approaching cold front, resulting in moderate buoyancy by the
late afternoon. Convergence along the front will be weak but still
sufficient for convective initiation, with the combination of
moderate buoyancy and moderate westerly flow aloft supporting strong
to severe storms. An initially more cellular mode could yield large
hail within the strongest storms. A quick transition towards more
linear modes is anticipated, with damaging gusts becoming the
primary severe risk within any strong line segments.

...MS/AL...
Afternoon thunderstorm development is anticipated across MS and AL
as a weak vorticity maximum progresses southeastward into the warm,
moist, and unstable environment in place across the region. Vertical
shear will be weak, and an outflow-dominant, multicellular mode is
expected. Even so, some clustering into one or more line segments
appears probable, resulting in scattered thunderstorm coverage.
Steep low-level lapse rates and relatively high cloud bases support
the potential for strong downdrafts with any more robust convection.

..Mosier/Bunting.. 08/18/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Aug 18 16:52:52 2026

ACUS01 KWNS 181652
SWODY1
SPC AC 181651

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1151 AM CDT Tue Aug 18 2026

Valid 181300Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL PLAINS/LOWER MISSOURI VALLEY AND UPPER MIDWEST...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible this afternoon and evening from the central Plains into the
lower Missouri Valley, as well as the Upper Midwest. Other storms
capable of severe wind gusts and hail will also be possible from the
Northern Rockies into the central High Plains this afternoon into
tonight.

...Central Plains into Lower Missouri Valley...
Scattered weakening thunderstorms continue across northeast
Kansas/southeast Nebraska into northern Missouri, reinforcing a
convective boundary that extends across the region. Thunderstorm redevelopment/intensification is conditionally possible through the
diurnal heating cycle near the boundary, which would carry with it
the potential for at least isolated hail/damaging winds.

A more certain scenario is expected this evening, when thunderstorm development/re-invigoration is more probable as the low-level jet
increases. Steep lapse rates and moderate vertical shear support the
potential for thunderstorms capable of large hail during the
initially more cellular mode. These storms will likely cluster
quickly, with a trend towards upscale growth into a
forward-propagating MCS with an increasing damaging wind potential
as it spreads toward/across Missouri.

...Northern Rockies through the Central High Plains...
A shortwave trough will progress southeastward from British
Columbia/Alberta into the northern Rockies. Thunderstorm development
is anticipated across the northern Rockies as this wave interacts
with the destabilized and buoyant airmass across the region.
Moderate westerly flow aloft with support the potential for more
organized storm structures and the development of several line
segments. These widely scattered thunderstorms are forecast to
progress east-southeastward this afternoon/evening, with additional
development possible from Wyoming into the central High Plains. The
moderate westerly flow aloft, high storm bases, and steep low-level
lapse rates support the potential for strong to severe wind gusts
and possibly some increased hail potential through evening/early
overnight as these storms progress east-southeastward toward the
richer reservoir of moisture/buoyancy across the central High
Plains, including western Nebraska/northeast Colorado/northwest
Kansas.

...Upper Midwest including portions of Iowa/Wisconsin/Michigan...
Low-level moisture is expected to increase across the Midwest ahead
of an approaching cold front, resulting in moderate buoyancy by late
afternoon. Near-frontal convergence will influence convective
initiation, with the combination of moderate buoyancy and seasonally
strong westerly flow aloft supporting strong to severe storms
including some initial/semi-discrete supercells, which could yield
large hail. A transition into linear segments is expected by
evening, with damaging wind gusts becoming the more prevalent severe
risk as storms spread generally southeastward.

...Mississippi/Alabama to northern Florida...
Scattered thunderstorm development is expected this afternoon,
particularly across portions of Mississippi into western/southern
Alabama and northern Florida. These storms will develop amidst a
very moist and unstable environment. Vertical shear will be weak,
with an outflow-dominant/multicellular mode expected. Some
clustering into one or more line segments appears probable,
resulting in scattered thunderstorm coverage. Steep low-level lapse
rates and relatively high cloud bases support the potential for
strong downdrafts capable of locally damaging winds.

..Guyer/Wendt.. 08/18/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Aug 18 17:14:26 2026

ACUS01 KWNS 181714
SWODY1
SPC AC 181712

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1212 PM CDT Tue Aug 18 2026

Valid 181630Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL PLAINS/LOWER MISSOURI VALLEY AND UPPER MIDWEST...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible this afternoon and evening from the central Plains into the
lower Missouri Valley, as well as the Upper Midwest. Other storms
capable of severe wind gusts and hail will also be possible from the
Northern Rockies into the central High Plains this afternoon into
tonight.

...Central Plains into Lower Missouri Valley...
Scattered weakening thunderstorms continue across northeast
Kansas/southeast Nebraska into northern Missouri, reinforcing a
convective boundary that extends across the region. Thunderstorm redevelopment/intensification is conditionally possible through the
diurnal heating cycle near the boundary, which would carry with it
the potential for at least isolated hail/damaging winds.

A more certain scenario is expected this evening, when thunderstorm development/re-invigoration is more probable as the low-level jet
increases. Steep lapse rates and moderate vertical shear support the
potential for thunderstorms capable of large hail during the
initially more cellular mode. These storms will likely cluster
quickly, with a trend towards upscale growth into a
forward-propagating MCS with an increasing damaging wind potential
as it spreads toward/across Missouri.

...Northern Rockies through the Central High Plains...
A shortwave trough will progress southeastward from British
Columbia/Alberta into the northern Rockies. Thunderstorm development
is anticipated across the northern Rockies as this wave interacts
with the destabilized and buoyant airmass across the region.
Moderate westerly flow aloft with support the potential for more
organized storm structures and the development of several line
segments. These widely scattered thunderstorms are forecast to
progress east-southeastward this afternoon/evening, with additional
development possible from Wyoming into the central High Plains. The
moderate westerly flow aloft, high storm bases, and steep low-level
lapse rates support the potential for strong to severe wind gusts
and possibly some increased hail potential through evening/early
overnight as these storms progress east-southeastward toward the
richer reservoir of moisture/buoyancy across the central High
Plains, including western Nebraska/northeast Colorado/northwest
Kansas.

...Upper Midwest including portions of Iowa/Wisconsin/Michigan...
Low-level moisture is expected to increase across the Midwest ahead
of an approaching cold front, resulting in moderate buoyancy by late
afternoon. Near-frontal convergence will influence convective
initiation, with the combination of moderate buoyancy and seasonally
strong westerly flow aloft supporting strong to severe storms
including some initial/semi-discrete supercells, which could yield
large hail. A transition into linear segments is expected by
evening, with damaging wind gusts becoming the more prevalent severe
risk as storms spread generally southeastward.

...Mississippi/Alabama to northern Florida...
Scattered thunderstorm development is expected this afternoon,
particularly across portions of Mississippi into western/southern
Alabama and northern Florida. These storms will develop amidst a
very moist and unstable environment. Vertical shear will be weak,
with an outflow-dominant/multicellular mode expected. Some
clustering into one or more line segments appears probable,
resulting in scattered thunderstorm coverage. Steep low-level lapse
rates and relatively high cloud bases support the potential for
strong downdrafts capable of locally damaging winds.

..Guyer/Wendt.. 08/18/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Tue Aug 18 19:54:28 2026

ACUS01 KWNS 181954
SWODY1
SPC AC 181952

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0252 PM CDT Tue Aug 18 2026

Valid 182000Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
UPPER MISSISSIPPI VALLEY INTO THE GREAT LAKES...ACROSS PORTIONS OF
THE PLAINS...AND ACROSS PARTS OF THE NORTHERN AND CENTRAL HIGH
PLAINS...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail will be
possible this afternoon and evening from the central Plains into the
lower Missouri Valley, as well as the Upper Midwest. Other storms
capable of severe wind gusts and hail will also be possible from the
Northern Rockies into the central High Plains this afternoon into
tonight.

...20z Update...
The primary adjustment for this update was the introduction of
additional 15% wind probabilities across southern Montana into
northern Wyoming and far western South Dakota. Latest GOES imagery
and lightning trends show deepening convection within the higher
terrain of southern to central MT. An approaching shortwave trough
will promote additional ascent and east/southeastward propagation
off the terrain through late afternoon and early evening. As this
occurs, thunderstorms will spread into a warm and deeply-mixed
environment featuring 0-3 km lapse rates on the order of 8-9 C/km
and sufficient buoyancy to sustain convection. Given this favorable thermodynamic profile and ample shear across the region (sampled by
18 UTC RAOBs from RIW and UNR), the potential for severe winds
appears higher than previously anticipated. Recent HRRR/RRFS
time-lagged ensemble guidance appears to be capturing this trend and
depicts higher severe wind potential than earlier solutions.

...Southeast Wyoming into Colorado and Nebraska...
The early stages of deepening convection is noted near the Casper,
WY area ahead of a weak mid-level disturbance and where daytime
heating has resulted in surface temperatures climbing into the low
80s. While this initial activity will likely remain sub-severe, the
potential for intensification should steadily increase as it spreads
southeast into a more moist air mass. Similarly, cumulus is noted
across north-central CO on the western fringe of the higher-quality
moisture. Guidance continues to show considerable spread regarding
convective coverage and evolution across both regions, but given
these observed trends and a fairly supportive environment downstream
of emerging convection, expanding hail and wind risk probabilities
appeared prudent.

...Northeast Kansas/western Missouri...
Latest guidance continues to show additional thunderstorm
development later tonight within a warm advection regime across
northeast KS into west/northwest MO. However, there has been a
notable northward trend in recent HRRR/RRFS solutions compared to
12z guidance. 15% hail and wind probabilities have been adjusted
northward to account for this trend.

..Moore.. 08/18/2026

.PREV DISCUSSION... /ISSUED 1212 PM CDT Tue Aug 18 2026/

...Central Plains into Lower Missouri Valley...
Scattered weakening thunderstorms continue across northeast
Kansas/southeast Nebraska into northern Missouri, reinforcing a
convective boundary that extends across the region. Thunderstorm redevelopment/intensification is conditionally possible through the
diurnal heating cycle near the boundary, which would carry with it
the potential for at least isolated hail/damaging winds.

A more certain scenario is expected this evening, when thunderstorm development/re-invigoration is more probable as the low-level jet
increases. Steep lapse rates and moderate vertical shear support the
potential for thunderstorms capable of large hail during the
initially more cellular mode. These storms will likely cluster
quickly, with a trend towards upscale growth into a
forward-propagating MCS with an increasing damaging wind potential
as it spreads toward/across Missouri.

...Northern Rockies through the Central High Plains...
A shortwave trough will progress southeastward from British
Columbia/Alberta into the northern Rockies. Thunderstorm development
is anticipated across the northern Rockies as this wave interacts
with the destabilized and buoyant airmass across the region.
Moderate westerly flow aloft with support the potential for more
organized storm structures and the development of several line
segments. These widely scattered thunderstorms are forecast to
progress east-southeastward this afternoon/evening, with additional
development possible from Wyoming into the central High Plains. The
moderate westerly flow aloft, high storm bases, and steep low-level
lapse rates support the potential for strong to severe wind gusts
and possibly some increased hail potential through evening/early
overnight as these storms progress east-southeastward toward the
richer reservoir of moisture/buoyancy across the central High
Plains, including western Nebraska/northeast Colorado/northwest
Kansas.

...Upper Midwest including portions of Iowa/Wisconsin/Michigan...
Low-level moisture is expected to increase across the Midwest ahead
of an approaching cold front, resulting in moderate buoyancy by late
afternoon. Near-frontal convergence will influence convective
initiation, with the combination of moderate buoyancy and seasonally
strong westerly flow aloft supporting strong to severe storms
including some initial/semi-discrete supercells, which could yield
large hail. A transition into linear segments is expected by
evening, with damaging wind gusts becoming the more prevalent severe
risk as storms spread generally southeastward.

...Mississippi/Alabama to northern Florida...
Scattered thunderstorm development is expected this afternoon,
particularly across portions of Mississippi into western/southern
Alabama and northern Florida. These storms will develop amidst a
very moist and unstable environment. Vertical shear will be weak,
with an outflow-dominant/multicellular mode expected. Some
clustering into one or more line segments appears probable,
resulting in scattered thunderstorm coverage. Steep low-level lapse
rates and relatively high cloud bases support the potential for
strong downdrafts capable of locally damaging winds.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Aug 19 01:02:30 2026

ACUS01 KWNS 190102
SWODY1
SPC AC 190100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Tue Aug 18 2026

Valid 190100Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS AND LOWER MISSOURI VALLEY...

...SUMMARY...
Thunderstorms with severe wind gusts and hail will be possible this
evening from parts of the central Plains into the lower Missouri
Valley. Isolated severe gusts and hail will also be possible in
parts of the central and northern High Plains, and from the Midwest
into the Great Lakes.

...Central Plains/Lower Missouri Valley...
The latest water vapor imagery shows west-northwesterly mid-level
flow over the central U.S. with a shortwave trough embedded in the
flow over western Kansas. At the surface, a moist airmass is located
from the mid Mississippi Valley westward into the central Plains,
where surface dewpoints are mostly from the upper 60s and lower 70s
F. Low-level convergence is maximized along and near a well-defined
outflow boundary located across central Kansas. Isolated severe
thunderstorms are ongoing near this boundary. In this area, moderate
deep-layer shear and steep low to mid-level lapse rates will be
favorable for isolated large hail and severe wind gusts over the
next few hours.

Further to the north across northern Kansas and southern Nebraska,
the RAP has strong instability analyzed with MLCAPE in the 3000 to
3500 J/kg range. Thunderstorms are currently ongoing in western
Nebraska and northeastern Colorado. These storms will move toward
the stronger instability over the next few hours. As this happens,
the storms may increase in intensity. If this were to occur, the
strong instability and moderate deep-layer shear over northwest
Kansas and southwest Nebraska would support a threat for hail and
isolated severe wind gusts. A second severe threat area is expected
to become active further east from northeast Kansas into
west-central Missouri as low-level flow increases this evening.
Thunderstorms are now developing in north-central Kansas and this
convection should expand in coverage over the next couple of hours.
The primary threat would be wind damage, especially if a short
intense line segment can become organized. Along its path, severe
wind gusts could exceed 70 mph...see MCD 2031.

...Midwest/Great Lakes...
The latest water vapor imagery shows a distinct shortwave trough
over the mid Mississippi Valley within west-northwesterly flow
aloft. At the surface, a moist airmass is located from the mid
Missouri Valley east-northeastward into the lower Michigan, where
surface dewpoints are mostly in the upper 60s and lower 70s F. An
axis of low-level convergence is located from northern Iowa into far
southern Wisconsin, along which thunderstorms are ongoing. A couple
of cells have remained discrete across northwestern Iowa, where an
axis of moderate instability is analyzed. As these cells move
southeastward into north-central Iowa this evening, isolated large
hail and a few severe wind gusts will be possible. Further east, the
storms have organized into a line segment over far southern
Wisconsin. These storms will have an isolated wind-damage threat
over the next couple of hours. A marginal severe threat may also
continue over parts of lower Michigan early this evening.

...Central and Northern High Plains...
West-northwesterly mid-level flow is currently located across the
northern Rockies and northern High Plains, with a distinct shortwave
trough moving through Montana. At the surface, an axis of low-level
moisture is present from eastern Wyoming into eastern Montana, along
which surface dewpoints are near 60 F. This is contributing to
MLCAPE around 1000 J/kg along parts of the moist axis. Isolated
strong to severe storms are ongoing near the moist axis in far
northeast Wyoming and in northeast Montana. Moderate deep-layer
shear and steep low to mid-level lapse rates will support a
potential for isolated severe gusts and hail this evening.

..Broyles.. 08/19/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Aug 19 05:59:40 2026

ACUS01 KWNS 190559
SWODY1
SPC AC 190557

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1257 AM CDT Wed Aug 19 2026

Valid 191200Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID MISSISSIPPI VALLEY...

...SUMMARY...
Thunderstorms with severe wind gusts and hail will be possible this
afternoon across the mid Mississippi Valley. Isolated severe gusts
and hail will also be possible from the lower to mid Missouri Valley
westward into the Great Plains. A few severe gusts could also occur
in southern Arizona and in the Southeast.

...Mid Mississippi Valley...
At mid-levels, a shortwave trough and an associated speed max will
move southeastward into the mid Mississippi Valley today. At the
surface, an outflow boundary associated with morning convection will
move southward into southern Missouri by midday. To the north of the
boundary, surface dewpoints will be in the 70s F. Moderate
instability is expected to develop in areas that are not impacted by
morning outflow. As low-level convergence becomes focused near the
boundary during the late afternoon and early evening, isolated to
scattered convective initiation is expected. From this convection, thunderstorms will likely develop and move eastward across the mid
Mississippi. One or two organized line segments will be possible
during the evening.

Early evening RAP forecast soundings in south-central Missouri,
where the strongest instability is expected, have 0-6 km shear
around 40 knots with precipitable water near 2 inches. MLCAPE is
expected to peak in the 2500 to 3000 J/kg range with 0-3 km lapse
rates around 7.5 C/km. This environment will support a severe threat
with supercells and multicell line segments. Severe wind gusts and
hail will be the primary hazards. The severe threat could persist
into the mid to late evening, with storms that are maintained by a
low-level jet that is forecast to strengthen in southeast Missouri.

...Great Plains...
Mid-level northwesterly flow will be in place across the Great
Plains today. At the surface, dewpoints in the 60s and 70s F will
contribute to moderate destabilization over much of the region.
During the afternoon, isolated storm development will be possible
within the unstable airmass from the lower to mid Missouri Valley
southwestward into the central Plains. A few severe gusts and hail
will be possible but the storms will remain isolated due to limited
large-scale ascent. The greater convective coverage is expected
further south in the higher terrain of eastern Colorado and
northeast New Mexico. Thunderstorms will likely form due to
topographic forcing during the mid to late afternoon and move east-southeastward into the lower elevations. Ahead of these storms,
RAP forecast soundings at 00Z in the northern Texas Panhandle and
southwest Kansas have 0-6 km shear around 40 knots with 0-3 km lapse
rates near 8 C/km, and surface-temperature dewpoint spreads
exceeding 30 degrees. This environment will support an isolated
potential for severe gusts.

...Southern Arizona...
Low-level moisture will be in place today across southern Arizona,
where surface dewpoints will be mostly in the 50s F. As surface
temperature warm, isolated to scattered convective initiation will
occur in the higher terrain of southeastern Arizona. These storms
will move west-southwestward toward an axis of instability. Steep
low to mid-level lapse rates and large temperature-dewpoint spreads
will support and isolated potential for severe gusts late this
afternoon into early evening.

...Southeast...
A very moist airmass will be in place today across the Southeast,
where surface dewpoints will be in the 70s F. As surface
temperatures warm, moderate instability will develop over much of
the region. Scattered thunderstorms are expected to develop and move
southward across parts of Mississippi and western Alabama. The deep
low-level moisture combined with steep low-level lapse rates will
support an isolated wind-damage threat during the mid to late
afternoon.

..Broyles/Thornton.. 08/19/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Aug 19 12:57:38 2026

ACUS01 KWNS 191255
SWODY1
SPC AC 191254

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 AM CDT Wed Aug 19 2026

Valid 191300Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS
INTO THE MID MS VALLEY AND SOUTHERN AZ....

...SUMMARY...
Thunderstorms with severe wind gusts and hail will be possible this
afternoon across the mid Mississippi Valley. Isolated severe gusts
and hail will also be possible from the lower to mid Missouri Valley
westward into the Great Plains. A few severe gusts could also occur
in southern Arizona and in the Southeast.

...Mid MO Valley...
Early-morning satellite imagery depicts a low-amplitude shortwave
trough moving through western SD/NE. Showers and thunderstorms are
ongoing downstream of this wave across central/eastern SD and north-central/northeast NE. Recent surface analysis place a corridor
of moderate low-level moisture (i.e. upper 60s dewpoints) from
eastern NE northwestward to a weak surface low over central SD.
Instability will likely build within this corridor as the shortwave
continues eastward, potential resulting increasing thunderstorm
coverage and intensity later this morning into the afternoon across
eastern NE. Vertical shear will be strong enough for organized storm
structures and the potential for a few supercells. This potential
will be largely dictated by how much the airmass can destabilize
amid the cloud cover and limited heating. Large hail is possible
within the initially more cellular activity, but a transition to a
more linear mode results in damaging gusts becoming the primary
hazard with eastward/southeastward extent.

...Ozarks into the Mid MS Valley...
Regional radar imagery shows a large cluster of showers and
thunderstorms progressing across the region. A few stronger updrafts
are possible within this cluster, but limited buoyancy downstream
and a weakening low-level jet are forecast to result in gradually
diminishing storm strength over the next few hours. The airmass is
forecast to gradually recover in the wake of this cluster, with
strong buoyancy (i.e. MLCAPE over 2000 J/kg) in place by the late
afternoon. The shortwave trough mentioned in the preceding paragraph
is forecast to continue southeastward, and ascent attendant to this
wave coupled with weak low-level convergence along the cold front
will support thunderstorm development within this destabilized
airmass this evening. Strengthening mid-level flow will result in
moderate to strong deep-layer vertical shear supportive of
supercells. Large hail and damaging gusts are the primary hazards,
but a strengthening low-level jet will result in enough low-level
shear to support the potential for a few tornadoes as well. Storms
will tend to cluster with eastward extent, with the threat for
damaging gusts persisting within these bowing line segments.

...Ohio Valley...
A somewhat secondary area of late afternoon/early evening
thunderstorm development is anticipated from central IL into central
IN and central OH. Moderate buoyancy and strong westerly flow aloft
support the potential for isolated supercells capable of large hail
and isolated damaging gusts.

...Central/Southern High Plains...
Surface analysis places 60s dewpoints into the Colorado Foothills
this morning, increasing into the upper 60s farther east/southeast
into southwest KS. Strong heating/mixing of this airmass is
anticipated this afternoon, promoting the development of moderate
buoyancy. Thunderstorm development is expected across the high
terrain before then progressing eastward into the lower elevations.
Moderate northwesterly flow aloft will be support organized storms
structures, and large hail is possible along the Foothill.
Thereafter, a trend towards an outflow-dominant storm mode will
result in strong to severe gusts across portions of the
central/southern High Plains. Higher probabilities may be needed in
later outlooks if guidance continues to indicate increased coverage.

...AZ...
The presence of monsoon moisture will support moderate buoyancy
across the lower elevations of south-central AZ during the late
afternoon. This should allow for storms that develop over the high
terrain to maintain intensity as they process southwestward into the
lower elevations this afternoon/evening. Steep low to mid-level
lapse rates and large temperature-dewpoint spreads will support the
potential for severe gusts.

...Southeast into northern FL...
A very moist airmass (i.e. dewpoints in the 70s) will be in place
today from MS into FL. Strong heating is anticipated, with high
temperatures in the upper 90s across much of the region. As surface temperatures warm, moderate instability will develop, with scattered thunderstorms expected amid modest low-level convergence from MS
into western/southern AL and across the FL Panhandle into northern
FL. The deep low-level moisture combined with steep low-level lapse
rates will support an isolated wind-damage threat during the mid to
late afternoon.

..Mosier/Bunting.. 08/19/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Wed Aug 19 16:36:44 2026

ACUS01 KWNS 191636
SWODY1
SPC AC 191634

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1134 AM CDT Wed Aug 19 2026

Valid 191630Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE MID AND LOWER MISSOURI VALLEY...THE MID MISSISSIPPI VALLEY...AND
SOUTHERN ARIZONA...

...SUMMARY...
Thunderstorms capable of severe wind gusts and hail will be possible
this afternoon across the lower to mid Missouri Valley, the mid
Mississippi Valley, and southern Arizona.

...Mid MO Valley...
Radar/visible satellite mosaic imagery depicts a small cluster of
severe thunderstorms immediately ahead of a migratory shortwave
trough moving southeast over the mid MO Valley. Some heating
downstream of this activity will result in temperatures warming and
the airmass gradually destabilizing amid filtered sunshine. Gradual
upscale growth is underway and should continue into the early
afternoon. Large hail and severe gusts 60-70 mph will be the
primary severe hazards as this cluster moves into adjacent portions
of NE/MO/IA later this afternoon.

...Ozarks into the Mid MS Valley...
Residual showers/thunderstorms from an overnight MCS over the
southeast MO into western KY vicinity will slowly dissipate this
afternoon with greater heating ensuing in the wake of these storms.
Models continue to show moderate destabilization by late this
afternoon ahead of the MO Valley upper vort. Weak low-level
convergence along an upstream cold front will support thunderstorm
development within this destabilized airmass this evening.
Strengthening mid-level flow will result in moderate to strong
deep-layer vertical shear supportive of supercells. Models vary
regarding the propensity for cellular mode to be maintained beyond
the initial storm development phase, casting doubt on supercell
longevity and tornado potential. Nonetheless, some strengthening of
850-mb flow during the evening may enable some mesocyclone potential
to persist, and an accompanying isolated risk for a tornado or two.
Otherwise, storms will tend to cluster with eastward extent, with
the threat for damaging gusts persisting within these bowing line
segments.

...Ohio Valley...
A somewhat secondary area of late afternoon/early evening
thunderstorm development is anticipated from central IL into central
IN and central OH. Moderate buoyancy and strong westerly flow aloft
supports the potential for isolated supercells capable of large hail
and isolated damaging gusts.

...Central/Southern High Plains...
A seasonably moist airmass will undergo strong heating/mixing and
result in moderate buoyancy by mid-late afternoon. Thunderstorm
development is expected across the higher terrain before then
progressing eastward into the lower elevations. Moderate
northwesterly flow aloft will support organized storms
structures, and large hail is possible along the Foothills.
Steep lapse rates and large temperature-dewpoint depressions will
lead to outflow-dominant storms capable of severe gusts with the
more intense cores/outflow.

...AZ...
The presence of monsoon moisture will support moderate buoyancy
across the lower elevations of south-central AZ during the late
afternoon. Scattered storms are expected to eventually develop
towards the early evening. Trends in model guidance showing a
cluster potentially evolving within an adequately moist/inverted-V
environment lend confidence in introducing a level 1 intensity
highlight for peak gusts in the 70-80 mph range.

...Southeast into northern FL...
A very moist airmass analyzed late this morning (mid to upper 70s F
surface dewpoints) will remain in place along the Gulf Coast. Strong
heating is anticipated, with high temperatures in the upper 90s
across much of the region. As surface temperatures warm, moderate
instability will develop, with scattered thunderstorms expected amid
modest low-level convergence from MS into western/southern AL and
across the FL Panhandle into northern FL. The deep low-level
moisture combined with steep low-level lapse rates will support an
isolated wind-damage threat during the mid to late afternoon.

..Smith/Wendt.. 08/19/2026

$$

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From COD Weather Processor @1:2320/107 to All on Wed Aug 19 19:59:38 2026

ACUS01 KWNS 191959
SWODY1
SPC AC 191957

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Wed Aug 19 2026

Valid 192000Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE LOWER MISSOURI VALLEY...THE MID MISSISSIPPI VALLEY...AND
SOUTHERN ARIZONA...

...SUMMARY...
Thunderstorms capable of severe wind gusts and hail will be possible
this afternoon across the lower Missouri Valley, the mid Mississippi
Valley, and southern Arizona.

...20z Update...
A compact, but severe, MCS has begun tracking eastward along a
residual/diffuse frontal zone into southeast NE. Based on the recent
18 UTC OAX RAOB, the MCS is beginning to orient more orthogonal to
the deep-layer bulk shear vector, which should continue to promote
storm organization and intensity. The potential for severe winds,
including winds near 75 mph, should continue through late afternoon
and early evening hours before moving into more stable air mass
across north-central MO. See MCD #2041 for additional short-term
details.

...Mid-Mississippi Valley/lower Ohio Valley...
Recent GOES visible imagery and surface observations show
temperatures rebounding into the low to mid 80s as skies clear ahead
of an approaching mid-level wave. This destabilization appears to be
on track with recent guidance, which suggests that initially discrete/semi-discrete storm development should begin by around
22-00 UTC across south-central MO on the western fringe of the
residual cold pool. Forecast soundings from this region depict
elongated hodographs conducive for large hail, including the
potential for hail up to 2 inches in diameter (based on sounding
analogs and hodograph structure). Given a favorable kinematic
environment, adequate buoyancy, and a signal in recent high-res
ensemble guidance for strong convection, a CIG 1 hail contour has
been introduced to portions of southern Missouri.

Elsewhere, only minor modifications were made based on recent
convective trends. See the discussion below and MCD #2040 for
additional details.

..Moore.. 08/19/2026

.PREV DISCUSSION... /ISSUED 1134 AM CDT Wed Aug 19 2026/

...Mid MO Valley...
Radar/visible satellite mosaic imagery depicts a small cluster of
severe thunderstorms immediately ahead of a migratory shortwave
trough moving southeast over the mid MO Valley. Some heating
downstream of this activity will result in temperatures warming and
the airmass gradually destabilizing amid filtered sunshine. Gradual
upscale growth is underway and should continue into the early
afternoon. Large hail and severe gusts 60-70 mph will be the
primary severe hazards as this cluster moves into adjacent portions
of NE/MO/IA later this afternoon.

...Ozarks into the Mid MS Valley...
Residual showers/thunderstorms from an overnight MCS over the
southeast MO into western KY vicinity will slowly dissipate this
afternoon with greater heating ensuing in the wake of these storms.
Models continue to show moderate destabilization by late this
afternoon ahead of the MO Valley upper vort. Weak low-level
convergence along an upstream cold front will support thunderstorm
development within this destabilized airmass this evening.
Strengthening mid-level flow will result in moderate to strong
deep-layer vertical shear supportive of supercells. Models vary
regarding the propensity for cellular mode to be maintained beyond
the initial storm development phase, casting doubt on supercell
longevity and tornado potential. Nonetheless, some strengthening of
850-mb flow during the evening may enable some mesocyclone potential
to persist, and an accompanying isolated risk for a tornado or two.
Otherwise, storms will tend to cluster with eastward extent, with
the threat for damaging gusts persisting within these bowing line
segments.

...Ohio Valley...
A somewhat secondary area of late afternoon/early evening
thunderstorm development is anticipated from central IL into central
IN and central OH. Moderate buoyancy and strong westerly flow aloft
supports the potential for isolated supercells capable of large hail
and isolated damaging gusts.

...Central/Southern High Plains...
A seasonably moist airmass will undergo strong heating/mixing and
result in moderate buoyancy by mid-late afternoon. Thunderstorm
development is expected across the higher terrain before then
progressing eastward into the lower elevations. Moderate
northwesterly flow aloft will support organized storms
structures, and large hail is possible along the Foothills.
Steep lapse rates and large temperature-dewpoint depressions will
lead to outflow-dominant storms capable of severe gusts with the
more intense cores/outflow.

...AZ...
The presence of monsoon moisture will support moderate buoyancy
across the lower elevations of south-central AZ during the late
afternoon. Scattered storms are expected to eventually develop
towards the early evening. Trends in model guidance showing a
cluster potentially evolving within an adequately moist/inverted-V
environment lend confidence in introducing a level 1 intensity
highlight for peak gusts in the 70-80 mph range.

...Southeast into northern FL...
A very moist airmass analyzed late this morning (mid to upper 70s F
surface dewpoints) will remain in place along the Gulf Coast. Strong
heating is anticipated, with high temperatures in the upper 90s
across much of the region. As surface temperatures warm, moderate
instability will develop, with scattered thunderstorms expected amid
modest low-level convergence from MS into western/southern AL and
across the FL Panhandle into northern FL. The deep low-level
moisture combined with steep low-level lapse rates will support an
isolated wind-damage threat during the mid to late afternoon.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 20 01:02:50 2026

ACUS01 KWNS 200102
SWODY1
SPC AC 200100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Wed Aug 19 2026

Valid 200100Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MID
MISSISSIPPI AND OHIO VALLEYS AND SOUTHERN ARIZONA...

...SUMMARY...
Thunderstorms capable of severe wind gusts and hail remain possible
this evening across the mid Mississippi and lower Ohio Valleys and
southern Arizona. More isolated strong storms are possible through
the evening across parts of the central/southern High Plains and
parts of the Southeast.

...Mid MS Valley to the lower OH Valley.
Evening water vapor imagery showed a broad trough and enhanced
northwesterly mid-level flow stretching from the southern Dakotas
into the mid MS Valley. Downstream of a flattened upper ridge over
the Southwest, this trough and stronger flow aloft should continue
eastward this evening aiding in thunderstorm development across
parts of the Mid MS and lower OH valleys this evening.

Several clusters of storms are already ongoing this evening near a
diffuse frontal zone across MO and into southern IL and western KY.
As the upper trough approaches, ascent form a 30+ kt southwesterly
low-level jet may support an increase in storm coverage, possibly
along the flank of the exist cluster in MO and farther south along
the frontal zone later this evening. Moderate, and likely somewhat
elevated buoyancy (2000-3000 J/kg MUCAPE), and 40-50 kt of
deep-layer shear will favor organized clusters or supercell
structures. Hail is possible, along with some damaging winds and
perhaps a tornado, especially if storms can develop into a more
coherent MCS. These storms should spread eastward overnight into the
lower OH Valley with a continued severe risk.

...Central and southern High Plains...
Scattered thunderstorms, including a few supercells are ongoing
across the central and southern High Plains within a broad upslope
flow regime. Aided by an upper trough with moderate northwesterly
flow aloft, organized storms structures capable of large hail should
continue along the Foothills and adjacent high plains this evening.
Steep lapse rates and large temperature-dew point depressions may
also favor a few severe gusts with the more intense cores/clusters
that can develop.

...AZ...
Scattered storms across the higher terrain of southern AZ should
continue to move toward the southwest into the Lower Deserts this
evening. Adequate monsoon moisture amid very hot temperatures (100
F+) and steep low-level lapse rates will support strong downdrafts
with severe gusts of 60-75 mph possible.

...Southeast...
Scattered thunderstorms are ongoing early this evening from MS into western/southern AL and across the FL Panhandle in association with
a weak MCV. A warm boundary layer and seasonably high moisture
content should continue to support scattered strong storms through
this evening. PWATs over 2 inches will favor strong water-loaded
downdrafts with isolated damaging gusts potential. Storms should
gradually diminish in coverage and intensity tonight as the boundary
layer stabilizes.

..Lyons.. 08/20/2026

$$

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From COD Weather Processor @1:2320/107 to All on Thu Aug 20 06:02:36 2026

ACUS01 KWNS 200602
SWODY1
SPC AC 200600

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Thu Aug 20 2026

Valid 201200Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE MID ATLANTIC...THE MIDWEST AND CENTRAL PLAINS....

...SUMMARY...
Scattered severe storms are possible today and tonight across parts
of the Mid Atlantic, posing a risk for damaging wind gusts. Large
hail and isolated wind damage will be possible with severe storms
from Nebraska into northwest Wisconsin.

...Mid Atlantic and central Appalachians...
A shortwave trough embedded within broader northwesterly flow aloft
is forecast to move eastward from the OH valley into the Mid
Atlantic through today. Embedded within a broader upper trough over
the eastern Great Lakes, this shortwave perturbation will serve as a
focus for convective development across the Mid Atlantic and central Appalachians this afternoon. As ascent overspreads the area, a warm
front is forecast to lift northward across southern PA, northern MD
into NJ and southern NY.

South of the front, a very moist air mass (dewpoints in the 70s F)
will lift northward. Despite poor low and mid-level lapse rates,
moderate buoyancy is expected south of the front and ahead of a
trailing lee trough into southern VA. Ongoing storms from a remnant
morning cluster may reintensify as they cross the Appalachians late
morning and early afternoon. Additional, possibly discrete,
development may occur east of the Blue Ridge and across the higher
terrain of southern PA and northern MD near the front by late
morning. 40-50 kt of deep-layer shear ahead of the front is forecast
to support a mix of supercells and line segments. Damaging winds and
isolated severe gusts appear probable. Enlarged low-level hodographs
near the front may also support a couple of tornadoes and marginally
severe hail with any more robust QLCS segments or supercells.

...Central Plains...
Strong northwesterly flow aloft will overspread a cold front moving
southward from the western Great Lakes into the central Plains.
Ahead of the front, warm temperatures and dewpoints in the mid to
upper 60s F will support moderate to large buoyancy by mid
afternoon. A shortwave impulse within the broader trough should
overspread the destabilizing air mass and aide in convective
development along the front across MN and SD, and farther south near
the front and surface trough intersection in central NE.

Forecast soundings show supercell wind profiles, with
elongated/straight hodographs aloft. Isolated to widely scattered
storms will develop by late afternoon/early evening, posing a risk
for large hail, severe wind gusts and perhaps a tornado. Some
significant hail (greater than 2 inch diameter) is possible across
the southern risk area given steeper mid-level lapse rates/cool
temperatures aloft and somewhat deeper low-level moisture. Some risk
for isolated damaging gusts may persist into the early overnight
across southern NE and northern KS if clustering can occur.

...Southeast...
South of the primary upper wave over parts of the Western Carolinas
and TN Valley, a surface trough in the lee of the Appalachians may
focus convective development during the afternoon. A few stronger
clusters with damaging gusts are possible, though weaker flow aloft
suggests more limited storm organization.

Additional scattered thunderstorms are expected again this afternoon
within a seasonably hot and humid air mass across the southeast and
lower MS Valley. Convective coverage is likely to focus along a
weakening cold front sagging southward across parts of AR/LA and
western MS and near a weak MCV across the central Gulf Coast. With
PWATs upwards of 2 inches, some potential for wet microbursts are
possible with the stronger storm clusters through early evening.

...AZ...
Strong heating beneath a prominent upper ridge will support another
round of scattered thunderstorms this afternoon and evening.
Seasonably rich monsoon moisture (dewpoints in the upper 50s to 60s
F) will support moderate destabilization amid modest easterly
mid-level flow. A few high-based clusters are possible, initially
over the higher terrain, before expanding west and south into the
lower elevations. This could support a few severe gusts given steep
lapse rates.

..Lyons/Thornton.. 08/20/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 20 12:48:12 2026

ACUS01 KWNS 201248
SWODY1
SPC AC 201246

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0746 AM CDT Thu Aug 20 2026

Valid 201300Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE MID-ATLANTIC...AND FROM THE CENTRAL PLAINS INTO THE UPPER
MISSISSIPPI VALLEY...

...SUMMARY...
Scattered severe storms are possible today and tonight across parts
of the Mid Atlantic, posing a risk for damaging wind gusts. Large
hail and isolated wind damage will be possible with severe storms
from Nebraska into northwest Wisconsin.

...Central Appalachians into the Mid-Atlantic...
Broad upper troughing currently extends from the northern Plains
through New England, with an embedded shortwave trough progressing
across the Mid MS Valley into the Lower OH Valley. Showers and
thunderstorms are ongoing ahead of this shortwave, and the
expectation is that these showers and thunderstorms will continue
weakening this morning. A moist airmass is in place downstream of
this wave (i.e. from the central Appalachians and upper OH Valley
into the Mid-Atlantic), and reintensification and/or new development
is expected ahead of this wave as it continues northeastward into
this diurnally destabilized region.

Surface low associated with this wave is currently over the IN/OH/KY
border vicinity. This low is forecast to deepen slightly as it moves northeastward just ahead of the parent shortwave trough. Modest
low-level moisture advection will precede this low, and a warm front
is forecast to lift northward across southern PA, northern MD, and
most of NJ. Despite poor lapse rates, ample low-level moisture south
of the front will support moderate buoyancy. Reintensification
and/or new thunderstorm development is expected first near the Blue
Ridge and across the higher terrain of southern PA and northern MD
before increasing in coverage and intensity with eastward extent. A
belt of slightly stronger mid-level flow will precede the shortwave,
resulting 40 to 50 kt of effective bulk shear. This is more than
sufficient to support a mix of supercells and organized line
segments. Damaging wind gusts will be the primary risk, but
southerly winds will enlarge low-level hodographs from the Delmarva
into central NJ, supporting the potential for a couple of tornadoes.

...Carolinas into the Southeast...
Ample low-level moisture and strong heating will result in an
unstable airmass from the Carolinas into much of the Southeast.
Low-level convergence along a cold front that will extend from the
western Carolinas into AR this afternoon will result in scattered
thunderstorm coverage. Vertical shear will be weak, and an
outflow-dominant storm structure is anticipated. Even so, moderate
to strong buoyancy and ample moisture (PW around 2") will support
occasionally strong water-loaded downbursts, particularly from
western TN into AL and MS where high temperatures in the upper 90s
are anticipated.

...Central Plains into the Upper MS Valley...
A reservoir of greater low-level moisture (i.e. dewpoints in the
upper 60s) currently extends from AR/eastern OK northwestward across
much of KS and into NE. Modest low-level moisture advection is
anticipated throughout this corridor today, as a tightening surface
pressure gradient results in stronger southerly surface winds. Mid
60s dewpoints could reach as far north as southwest MN. Moderate to
strong buoyancy will develop within this corridor, with the greatest
buoyancy likely from the CO/KS/NE border vicinity northeastward into
southeast SD. At the same time, a cold front will progress
southeastward across western MN, central SD and western NE,
interacting with this buoyancy to support thunderstorm development. Thunderstorm initiation is anticipated first across the Upper MS
Valley before expanding southwestward.

Moderate northwesterly flow aloft will support supercell wind
profiles, with elongated/straight hodographs, and the threat for all
severe hazards. Large to very large hail (i.e. greater than 2 inch
diameter) will be the primary severe hazard, particularly during the
early evening as the storms move into greater instability. Isolated
strong to severe gusts (i.e. 55 to 75 mph) are possible as well.
Given the supercellular storm mode and low-level southerly flow, a low-probability tornado risk also exists.
Some risk for isolated damaging gusts may persist into the early
overnight across southern NE and northern KS if clustering can
occur.

...AZ...
Another round of scattered thunderstorms this afternoon and evening
amid seasonably rich monsoon moisture (dewpoints in the upper 50s to
60s F) and moderate buoyancy. The lower elevations will be
characterized by greater convective inhibition than yesterday, with
the overall buoyancy slightly lower as well. Consequently, despite a
similar upper pattern, the overall potential for strong gusts is
expected to be lower than yesterday. Even so, isolated gusts are
still possible as storms move off the high terrain into the deeply
mixed airmass over the lower elevations.

..Mosier/Bunting.. 08/20/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 20 16:35:24 2026

ACUS01 KWNS 201635
SWODY1
SPC AC 201633

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1133 AM CDT Thu Aug 20 2026

Valid 201630Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE MID-ATLANTIC...PARTS OF THE SOUTHEAST...AND FROM THE CENTRAL
PLAINS INTO THE UPPER MISSISSIPPI VALLEY...

...SUMMARY...
Scattered severe storms are possible this afternoon into this
evening across parts of the Mid Atlantic, posing a risk for a couple
of tornadoes and damaging wind gusts. Large hail and isolated wind
damage will be possible late today into tonight with severe storms
from Nebraska into northwest Wisconsin. Scattered damaging gusts
are possible over parts of the Deep South this afternoon into the
early evening.

...Central Appalachians into the Mid-Atlantic...
Radar mosaic late this morning showed a couple of weak convectively
related vorticity maxima moving east across the central and southern Appalachians (i.e., southwest PA, eastern KY). One of these lead
disturbances was sampled by the WSR-88D VAD at Jackson, KY, with an
upstream shortwave trough over the OH Valley moving towards the
Mid-Atlantic states.

The airmass across the Mid-Atlantic into the Carolinas will continue
to heat amid patchy but thinning cloud cover. Model guidance shows
moderate buoyancy developing by early to mid afternoon from the
southern Appalachians northward into the northern Mid-Atlantic
region. A belt of stronger 700-500 mb westerly flow (30-45 kt) will
overspread the northern half of VA northward into PA/NJ. Beneath
this stronger flow, southerly low-level flow veering and
strengthening with height will support hodographs favorable for
organized severe storms, including supercells and organized line
segments. The latest model guidance shows a few simulated
supercells developing in the area centered over MD and the upper
Chesapeake Bay vicinity during the 20-00z timeframe. This scenario
seems plausible given some low-level enlargement to the hodograph
and effective shear around 40 kt. A tendency for upscale growth
into a line segment is expected as this activity moves east towards
the coast during the evening. A couple of supercell tornadoes are
possible with this activity, in addition to a line-embedded
mesovortex and scattered damaging gusts.

...Carolinas into the TN Valley and lower MS Valley...
Ample low-level moisture and strong heating will result in an
unstable airmass from the Carolinas into much of the Southeast.
Low-level convergence along a cold front that will extend from the
western Carolinas into AR this afternoon will result in scattered
thunderstorm coverage as 2500-4000 J/kg MLCAPE develops by mid
afternoon. High PW (in excess of 2 inches) and steep 0-3 km lapse
rates and modest westerly to west-northwesterly flow will favor
damaging downbursts with the stronger southeast-moving clusters.

...Central Plains into the Upper MS Valley...
A tongue of relatively rich low-level moisture (mainly 60s F surface
dewpoints) will extend from the central Great Plains northward ahead
of a cold front, which is forecast to be draped from western MN into
western NE this afternoon. Thunderstorm initiation is anticipated
first across the Upper MS Valley before expanding southwestward.

Moderate northwesterly flow aloft will support supercell wind
profiles, with elongated/straight hodographs, and the threat for all
severe hazards. Large to very large hail (i.e. greater than 2 inch
diameter) will be the primary severe hazard, particularly during the
early evening as the storms move into greater instability. Isolated
strong to severe gusts (i.e. 55 to 75 mph) are possible as well.
Given the supercellular storm mode and low-level southerly flow, a low-probability tornado risk also exists. Some risk for isolated
damaging gusts may persist into the early overnight across southern
NE and northern KS if clustering can
occur.

...AZ...
Not much change from prior forecast thinking in that isolated to
widely scattered storms are forecast but a generally lower risk for
severe gusts is anticipated later today into this evening. Steep
lapse rates and inverted-V profiles will support an isolated risk
for severe gusts with the more intense downdrafts.

..Smith/Wendt.. 08/20/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Thu Aug 20 19:57:46 2026

ACUS01 KWNS 201957
SWODY1
SPC AC 201955

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Thu Aug 20 2026

Valid 202000Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE MID-ATLANTIC...PARTS OF THE SOUTHEAST...AND FROM THE CENTRAL
PLAINS INTO THE UPPER MISSISSIPPI VALLEY...

...SUMMARY...
Scattered severe storms are possible this afternoon into this
evening across parts of the Mid Atlantic, posing a risk for a couple
of tornadoes and damaging wind gusts. Large hail and isolated wind
damage will be possible late today into tonight with severe storms
from Nebraska into northwest Wisconsin. Scattered damaging gusts
are possible over parts of the Deep South this afternoon into the
early evening.

...20z Update...
The previous forecast largely remains on track with only minor
adjustments made based on recent convective trends and recent
guidance. Regional radar mosaics show the development of discrete
and semi-discrete supercells across the northern MD into southern PA
ahead of a mid-level perturbation and weak cold front. The recent 18
UTC IAD sounding sampled modest buoyancy (around 1000 J/kg MLCAPE),
which seems to be more marginal compared to recent RAP mesoanalysis
MLCAPE depictions. Nonetheless, strong shear was sampled by this
RAOB, including just under 200 m2/s2 effective SRH. This environment
likely exists downstream into far southeast PA and western NJ and
warranted a slight northward expansion of the CIG1 tornado contour.
Confidence in convective coverage with southwestward extent into
southern VA and NC remains limited based on trends in
radar/satellite trends and latest high-res guidance. Other forecast
thoughts outlined in the previous discussion below remain on track.

...Northern MS/AL...
Convection is developing along/ahead of a weak surface front and
mid-level wave across southeast AR into northern MS. This aligns
well with recent guidance, especially RRFS solutions, which depict
increasing thunderstorm coverage through early evening. Wind and
hail probabilities have been adjusted slightly across northern
AL/southern TN to reflect these solutions and capture areas where
air mass recovery continues.

...Northern MN...
A surface low is becoming apparent in surface observations and GOES
visible imagery across northern MN with early stages of convection
noted over the past 45 minutes. With 64-66 F dewpoints spreading
north towards north-central MN, some potential exists for more
robust convection than previously depicted by guidance. Recent
RRFS/HRRR time-lagged ensembles have also trended slightly north
with the strongest UH signals, which matches these recent
observations and warranted a northward expansion of probabilities.

Elsewhere, the forecast outlined below remains on track. See MCD
#2053 for additional short-term details regarding the near-term
severe threat across north-central NE.

..Moore.. 08/20/2026

.PREV DISCUSSION... /ISSUED 1133 AM CDT Thu Aug 20 2026/

...Central Appalachians into the Mid-Atlantic...
Radar mosaic late this morning showed a couple of weak convectively
related vorticity maxima moving east across the central and southern Appalachians (i.e., southwest PA, eastern KY). One of these lead
disturbances was sampled by the WSR-88D VAD at Jackson, KY, with an
upstream shortwave trough over the OH Valley moving towards the
Mid-Atlantic states.

The airmass across the Mid-Atlantic into the Carolinas will continue
to heat amid patchy but thinning cloud cover. Model guidance shows
moderate buoyancy developing by early to mid afternoon from the
southern Appalachians northward into the northern Mid-Atlantic
region. A belt of stronger 700-500 mb westerly flow (30-45 kt) will
overspread the northern half of VA northward into PA/NJ. Beneath
this stronger flow, southerly low-level flow veering and
strengthening with height will support hodographs favorable for
organized severe storms, including supercells and organized line
segments. The latest model guidance shows a few simulated
supercells developing in the area centered over MD and the upper
Chesapeake Bay vicinity during the 20-00z timeframe. This scenario
seems plausible given some low-level enlargement to the hodograph
and effective shear around 40 kt. A tendency for upscale growth
into a line segment is expected as this activity moves east towards
the coast during the evening. A couple of supercell tornadoes are
possible with this activity, in addition to a line-embedded
mesovortex and scattered damaging gusts.

...Carolinas into the TN Valley and lower MS Valley...
Ample low-level moisture and strong heating will result in an
unstable airmass from the Carolinas into much of the Southeast.
Low-level convergence along a cold front that will extend from the
western Carolinas into AR this afternoon will result in scattered
thunderstorm coverage as 2500-4000 J/kg MLCAPE develops by mid
afternoon. High PW (in excess of 2 inches) and steep 0-3 km lapse
rates and modest westerly to west-northwesterly flow will favor
damaging downbursts with the stronger southeast-moving clusters.

...Central Plains into the Upper MS Valley...
A tongue of relatively rich low-level moisture (mainly 60s F surface
dewpoints) will extend from the central Great Plains northward ahead
of a cold front, which is forecast to be draped from western MN into
western NE this afternoon. Thunderstorm initiation is anticipated
first across the Upper MS Valley before expanding southwestward.

Moderate northwesterly flow aloft will support supercell wind
profiles, with elongated/straight hodographs, and the threat for all
severe hazards. Large to very large hail (i.e. greater than 2 inch
diameter) will be the primary severe hazard, particularly during the
early evening as the storms move into greater instability. Isolated
strong to severe gusts (i.e. 55 to 75 mph) are possible as well.
Given the supercellular storm mode and low-level southerly flow, a low-probability tornado risk also exists. Some risk for isolated
damaging gusts may persist into the early overnight across southern
NE and northern KS if clustering can
occur.

...AZ...
Not much change from prior forecast thinking in that isolated to
widely scattered storms are forecast but a generally lower risk for
severe gusts is anticipated later today into this evening. Steep
lapse rates and inverted-V profiles will support an isolated risk
for severe gusts with the more intense downdrafts.

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 21 00:54:46 2026

ACUS01 KWNS 210054
SWODY1
SPC AC 210052

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 PM CDT Thu Aug 20 2026

Valid 210100Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
THE UPPER MIDWEST TO THE CENTRAL PLAINS...THE SOUTHEAST AND MID
ATLANTIC TO THE SOUTHERN APPALACHIANS...

...SUMMARY...
Scattered severe storms remain likely this evening across parts of
the southern Mid Atlantic and Appalachians with a risk for damaging
wind gusts and a brief tornado. Large hail and isolated damaging
winds are expected with severe storms from Nebraska into Wisconsin
and Minnesota. Scattered damaging gusts are possible over parts of
the Deep South this evening.

...Mid Atlantic into the TN valley and the Carolinas...
Evening water vapor imagery showed a shortwave trough moving across
southern PA and the DelMarVa toward the Atlantic Coast this evening.
Numerous thunderstorms were ongoing ahead of the upper wave near a
frontal zone from southern NY and PA southward into VA. As the wave
moves offshore through the remainder of this evening, the front will
begin to surge eastward with the associated moist and unstable air
mass eventually moving offshore with it. Damaging gusts and a brief
tornado will remain possible with a mix of supercells and line
segments ahead of the front before moving offshore late this
evening.

Farther south, more isolated convection remains ongoing across
southern VA and the western Carolinas. Displaced from the stronger
ascent of the passing shortwave trough and flow aloft, storm
coverage should remain lower here. However, moderate buoyancy and
25-35 kt of deep-layer shear will support some risk for organized storms/clusters with damaging gusts into the early overnight hours
across eastern TN, northern AL and the western Carolinas.

...Midwest and central Plains...
Isolated to widely scattered strong/severe thunderstorms have
developed and should continue to do so ahead of a cold front and
surface trough from northern MN, the eastern Dakotas and into NE
this evening. Moderate to large buoyancy and strong northwesterly
flow will remain favorable for organized supercells with hail and
severe gusts. An isolated tornado and very large hail are also
possible, particularly from eastern SD into NE where locally
stronger buoyancy may support maximum diameters of 2-3 inches.

Some clustering and a local increase in the damaging wind risk may
occur across southern NE and northern KS this evening as storms move
nearly due south. Very hot surface temperatures and steep lapse
rates in low-levels could support few gusts of 65-75+ mph before
convection slowly weakens after sunset.

...Southeast...
Scattered thunderstorms are ongoing ahead of a weak cold front from southeastern OK, into southern AR and LS/MS this evening. Additional
scattered storms were noted near a weak MCV along the central Gulf
Coast. Modestly enhanced northwesterly flow may maintain a few
stronger clusters through this evening within a warm and seasonably
moist air mass. While mid-level lapse rates are generally poor,
2000-3000 J/kg of MLCAPE and PWATs over 2 inches will support some
potential for damaging gusts with stronger downdrafts and storm
clusters.

...AZ...
Beneath the upper ridge, scattered thunderstorms are ongoing this
evening mostly over the higher terrain of central AZ. Expectations
are for these storms to persist this evening owing to very hot
surface temperatures and a seasonably moist boundary layer. Steep
lapse rates and inverted-V profiles will support an isolated risk
for severe gusts with the more intense downdrafts this evening.

..Lyons.. 08/21/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 21 05:59:00 2026

ACUS01 KWNS 210558
SWODY1
SPC AC 210556

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1256 AM CDT Fri Aug 21 2026

Valid 211200Z - 221200Z

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

...SUMMARY...
Scattered damaging hail (some greater than 2 inch diameter) and
severe wind gusts may occur over parts of the central Plains this
afternoon and evening. Scattered storms, some with severe wind gusts
and hail, also are possible across parts of the Midwest. Scattered
to numerous storms with damaging wind guts are possible over the
Carolinas and Southeast.

...Central Plains...
Mid-level ridging over the western US is forecast to intensify,
strengthening northwesterly flow aloft over much of the central US.
Several embedded disturbances will pass overhead with the enhanced northwesterlies through the day. A surface low will move
southeastward through the Great Lakes as a weak trailing cold front
moves southward through the central Plains and Midwest.

Ahead of the front, a plume of steep mid-level lapse rates will
shift eastward across the central Plains toward the Mid-MO Valley
atop a corridor of rich low-level moisture. Diurnal destabilization
should result in 3000-4000 J/kg of MLCAPE from SD to NE. Isolated to
widely scattered thunderstorm development is expected from the Black
Hills southeastward along the cold front. Elongated/straight
hodographs and 45+ kt effective shear will favor initial supercells.
Large to very large hail (some greater than 2 inches diameter) will
be possible. With time, a forward propagating cluster or two may
develop and move southeast across parts of NE and KS with the
potential for severe gusts (a few near 70-80 mph). It is unclear
exactly how far southeast any storms will persist overnight, but any
more substantial clustering could allow at least an isolated severe
threat to continue into early Saturday.

A much drier and hotter environment over the High Plains to the west
could also support isolated to widely scattered high-based storms
from eastern CO into western KS. Very steep lapse rates in the
lowest 2-3 km with modest buoyancy aloft could allow a few severe
gusts.

...Midwest...
Beneath the upper trough over the western Great Lakes, cool
mid-level temperatures and robust surface moisture should result in
moderate destabilization from WI into eastern IA and northwest IL.
Scattered thunderstorms by mid afternoon ahead of the cold front
spreading southeastward. Enhanced northwesterly flow with deep-layer
shear of 30-40 kt will promote a mix of organized clusters and
supercells. The large buoyancy will support a risk for damaging
gusts and some hail.

...Southeast and Gulf Coast...
A broad upper trough will move across the central US into parts of
the southern Appalachians while a weak cold front moves southward
from the mid Atlantic today and tonight. Weak ascent from the upper
trough and near the front should focus diurnal thunderstorm activity
across the Carolians and southern Appalachians. Warm surface
temperatures and plentiful boundary-layer moisture will support
large buoyancy (3000+ J/kg MLCAPE) through the afternoon and evening
despite modest mid-level lapse rates. With scattered to numerous
storms expected, a few organized clusters may emerge with a risk
primarily for damaging wind gusts. Slight enhancement of the
westerly flow aloft could also support some isolated hail with the
stronger updrafts.

Farther south and west, a very humid and warm air mass is forecast
to become strongly unstable by early afternoon across the lower MS
Valley and Gulf Coast. Scattered to numerous thunderstorms are
expected along prior outflows and a weak, southward moving cold
front from East TX into LA/MS. The very strong buoyancy and high
PWAT content will support clustering and strong downdrafts with
sporadic damaging gust potential. Otherwise, weak vertical shear
will limit overall organization.

..Lyons/Weinman.. 08/21/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 21 12:44:50 2026

ACUS01 KWNS 211244
SWODY1
SPC AC 211242

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0742 AM CDT Fri Aug 21 2026

Valid 211300Z - 221200Z

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

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail (some
2+ inches) and severe winds may occur over parts of the central
Plains into the Midwest this afternoon and evening. Damaging winds
will also be possible with scattered to numerous thunderstorms
across portions of the Carolinas and Southeast.

...Central Plains into the Midwest...
Elevated and widely spaced thunderstorms have developed this morning
from far southwest SD into central NE, and separately across eastern
OK. Weak low-level warm/moist advection is aiding this activity, and
ascent associated with a northwesterly mid/upper-level jet may also
be supporting the central Plains convection. Evolution of the
ongoing thunderstorms across NE remains unclear, as the airmass
downstream into southeast NE/northern KS will gradually destabilize
through the day. One possibility is for convection to slowly
strengthen and eventually develop into a bowing cluster this
afternoon across these areas, with an associated risk for
severe/damaging winds.

Another scenario is for this morning activity to weaken, and then
for isolated supercells to potentially develop later today in a
rather unstable airmass and strongly sheared mid/upper-level
northwesterly flow regime along/south of a front. Large hail (some
2+ inches) would be a threat with any sustained supercells, and
severe gusts could also occur as lapse rates become steepened.
Either scenario appears plausible, with recent high-resolution
guidance varying on possible solutions, including the potential for
one or more clusters to develop and persist tonight. Have therefore
maintained the Slight Risk across the central Plains with minimal
changes.

Thunderstorms are also occurring this morning over parts of WI to
the east of a weak surface low and associated mid-level
perturbation. While effective bulk shear is forecast to remain
fairly modest (around 20-30 kt), a mix of multicells and marginal
supercells is expected to develop later this afternoon across parts
of southern WI into northern/central IL along and ahead of a weak
front. Severe hail may occur with any persistent cells, while the
threat for damaging winds should increase as small clusters form and
spread east-southeastward through the early evening. While low-level
flow is not forecast to become overly strong, sufficient veering
with height through low/mid levels should exist to support modest
low-level hodograph curvature and some risk for a brief tornado.

...Carolinas into the Southeast/Lower Mississippi Valley...
Convection continues this morning along/ahead of a surface cold
front from central AL northeastward into the western NC. Modest
large-scale ascent associated with a weak mid-level shortwave trough
over the TN Valley is likely aiding this activity. Around 20-30 kt
of mid-level flow should be present today over parts of the
Carolinas, with similar values of deep-layer shear forecast.
Moderate to locally strong instability is expected to develop this
afternoon ahead of the front across the central/eastern Carolinas,
as a rather moist low-level airmass remains over these areas.
Thunderstorms should gradually increase in both coverage and
intensity this afternoon, with sufficient deep-layer shear for some
updraft organization. Multicell clusters capable of producing
isolated to scattered damaging winds should be the main threat as
low-level lapse rates become steepened with filtered daytime
heating. Still, some of the stronger cores could produce occasional
hail as well, even though lapse rates aloft appear poor. This
convection will spread towards the Atlantic Coast through the
afternoon/early evening before eventually weakening with the loss of
daytime heating.

Farther south across the Gulf Coast states into the lower MS Valley,
mid-level flow and related deep-layer shear are forecast to be
weaker (generally less than 20 kt). Even so, at least an isolated
threat for damaging winds should exist with scattered thunderstorms
that develop along/south of the front and spread southward through
the afternoon, as the airmass should become quite unstable with
robust diurnal heating.

..Gleason/Broyles.. 08/21/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 21 16:25:54 2026

ACUS01 KWNS 211625
SWODY1
SPC AC 211624

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1124 AM CDT Fri Aug 21 2026

Valid 211630Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS...MIDWEST...LOWER MS VALLEY...AND CAROLINAS...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail (some
2+ inches) and severe winds may occur over parts of the central
Plains into the Midwest this afternoon and evening. Damaging winds
will also be possible with scattered to numerous thunderstorms
across portions of the Carolinas and northern Gulf Coast states.

...Central Plains into the Midwest...
A northwest flow regime will result in a weakly forced and in a
limited confidence severe setup across the central Plains. Ongoing
widely scattered storm activity may persist and reinvigorate during
the afternoon, or new development occurs along residual outflow as
the airmass becomes moderately to strongly unstable. Forecast
sounding profiles show moist low levels beneath steep 700-500 mb
lapse rates amid veering and strengthening flow with height. Large
hail (some 2+ inches) would be a threat with any sustained
supercells along with severe gusts (60-75 mph). If a small cluster
can eventually develop, the severe-wind hazard would likely focus
with these potential storms.

A small west to east oriented band of storms is moving south across
southern WI to the east of a weak surface low and immediately
downstream of an associated mid-level perturbation. While effective
bulk shear is forecast to remain fairly modest (around 20-30 kt), a
mix of multicells and marginal supercells is expected to develop
later this afternoon across parts of southern WI into
northern/central IL along and ahead of a weak front. Severe hail
may occur with any persistent cells, while the threat for damaging
winds should increase as small clusters form and spread
east-southeastward through the early evening. While low-level
flow is not forecast to become overly strong, sufficient veering
with height through low/mid levels should exist to support modest
low-level hodograph curvature and some risk for a brief tornado.

...Carolinas...
Weakened shower/thunderstorm activity associated with an MCV over
the western Carolinas will likely dissipate during the early
afternoon. However, renewed storm development is forecast in
proximity to this upper disturbance, as well as near residual
outflow from the earlier convection and a surface cool front draped
from the GA/SC Piedmont northeastward into the coastal plain of
eastern NC. Strong heating of a seasonably moist boundary layer
will result in strong instability by mid afternoon. Sufficient
deep-layer shear for some organized multicell potential will be
greatest near the upper-level feature. Farther southeast near the
SC Low Country, weaker flow will result in a pulse thunderstorm
mode. Scattered damaging gusts are possible with the stronger
thunderstorms through the early evening before nocturnal stability
weakens storms and ends the severe threat.

...North TX east into northern Gulf Coast states...
Antecedent outflow from overnight storm clusters over the lower MS
Valley and AL will serve as a focus for storm development this
afternoon. Farther west, a more pronounced decaying MCS and
associated southward-moving MCV over east-central OK will also focus
storm activity across east TX into western LA. The 12 UTC Little
Rock raob showed a belt of enhanced flow around the 4-5 km layer
(35-40 kt). Other than a localized corridor where moderate
northerly flow will overspread a strongly destabilizing boundary
layer, slightly weaker northerly to northeasterly flow will
encompass this larger region from north TX to Mobile Bay.
Nonetheless, the development of very steep 0-3 km lapse rates (9 deg
C/km) by early to mid afternoon and high PW (1.75-2.0 inches) will
support scattered wind damage with the more intense downdrafts (most
likely and concentrated from east TX through southern MS).

...Northern Great Basin into the Snake Valley...
A mid-level vorticity max rotating northward around the western
periphery of the Four Corners upper high, will move into northern
NV/UT by late afternoon. Deep inverted-V profiles will develop by
mid afternoon with a dry sub-cloud layer featuring large surface temperature-dewpoint spreads. A linear cluster of storms is
expected to evolve and move north across the NV/UT/ID vicinity
during the late afternoon and early evening. Evaporatively cooled
downdrafts will be potentially capable of severe gusts 60-75 mph.

..Smith/Chalmers.. 08/21/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Fri Aug 21 20:02:32 2026

ACUS01 KWNS 212002
SWODY1
SPC AC 212000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Fri Aug 21 2026

Valid 212000Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS...MIDWEST...LOWER MS VALLEY...AND CAROLINAS...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail (some
2+ inches) and severe winds may occur over parts of the central
Plains into the Midwest this afternoon and evening. Damaging winds
also remain possible with scattered to numerous thunderstorms across
portions of the Carolinas and northern Gulf Coast states.

...20z Update...

...Lower MS Valley and Carolinas...
The forecast generally remains on track with only a minor eastward
expansion of the 15% wind probabilities in southern Alabama and the
far western Florida Panhandle. Modestly stronger low-to-mid level
flow (evident in the MOB VWP) and favorable thermodynamic profiles
(steep low-level lapse rates and high PW) should support stronger
downbursts and scattered damaging wind gusts, similar to areas
farther east. See Mesoscale Discussion #2069 for additional
short-term details.

...Midwest...
The Level 1/Marginal risk and Level 2/Slight risk areas were
expanded slightly northwestward based on observed convective
development ongoing across as of 1945 UTC across southwestern
Wisconsin. Some consideration was given to adding a targeted 5%
tornado probability area along the remnant outflow boundary
extending from southeast of Rockford, IL, into southwestern
Wisconsin; however, uncertainty regarding the longevity of a
supercellular storm mode (owing to the potential for cell
mergers/interactions) and the presence of only modest low-level
hodograph curvature/SRH precludes a 5% area at this time. See
Mesoscale Discussion #2070 for additional short-term details.

...Central Plains...
Latest high-res guidance has poorly captured the evolution of
morning and ongoing convection across portions of central and
eastern Nebraska through early this afternoon, which lends
uncertainty to the evolution of the severe threat through the rest
of the period. Given the continued potential for ongoing convection
to intensify and/or for additional redevelopment through the
evening, however, severe probabilities have been maintained with
only minor expansions made to the CIG1 wind and hail areas.

...Northern Great Basin into the Snake Valley...
Convective development is ongoing across portions of central/eastern
Nevada, with thunderstorms forecast to evolve northward through the
afternoon. The 5% wind probabilities and CIG1 area were expanded
westward and northward based on the placement of ongoing
thunderstorm activity and the latest HRRR/RRFS runs.

..Chalmers/Moore.. 08/21/2026

.PREV DISCUSSION... /ISSUED 1124 AM CDT Fri Aug 21 2026/

...Central Plains into the Midwest...
A northwest flow regime will result in a weakly forced and in a
limited confidence severe setup across the central Plains. Ongoing
widely scattered storm activity may persist and reinvigorate during
the afternoon, or new development occurs along residual outflow as
the airmass becomes moderately to strongly unstable. Forecast
sounding profiles show moist low levels beneath steep 700-500 mb
lapse rates amid veering and strengthening flow with height. Large
hail (some 2+ inches) would be a threat with any sustained
supercells along with severe gusts (60-75 mph). If a small cluster
can eventually develop, the severe-wind hazard would likely focus
with these potential storms.

A small west to east oriented band of storms is moving south across
southern WI to the east of a weak surface low and immediately
downstream of an associated mid-level perturbation. While effective
bulk shear is forecast to remain fairly modest (around 20-30 kt), a
mix of multicells and marginal supercells is expected to develop
later this afternoon across parts of southern WI into
northern/central IL along and ahead of a weak front. Severe hail
may occur with any persistent cells, while the threat for damaging
winds should increase as small clusters form and spread
east-southeastward through the early evening. While low-level
flow is not forecast to become overly strong, sufficient veering
with height through low/mid levels should exist to support modest
low-level hodograph curvature and some risk for a brief tornado.

...Carolinas...
Weakened shower/thunderstorm activity associated with an MCV over
the western Carolinas will likely dissipate during the early
afternoon. However, renewed storm development is forecast in
proximity to this upper disturbance, as well as near residual
outflow from the earlier convection and a surface cool front draped
from the GA/SC Piedmont northeastward into the coastal plain of
eastern NC. Strong heating of a seasonably moist boundary layer
will result in strong instability by mid afternoon. Sufficient
deep-layer shear for some organized multicell potential will be
greatest near the upper-level feature. Farther southeast near the
SC Low Country, weaker flow will result in a pulse thunderstorm
mode. Scattered damaging gusts are possible with the stronger
thunderstorms through the early evening before nocturnal stability
weakens storms and ends the severe threat.

...North TX east into northern Gulf Coast states...
Antecedent outflow from overnight storm clusters over the lower MS
Valley and AL will serve as a focus for storm development this
afternoon. Farther west, a more pronounced decaying MCS and
associated southward-moving MCV over east-central OK will also focus
storm activity across east TX into western LA. The 12 UTC Little
Rock raob showed a belt of enhanced flow around the 4-5 km layer
(35-40 kt). Other than a localized corridor where moderate
northerly flow will overspread a strongly destabilizing boundary
layer, slightly weaker northerly to northeasterly flow will
encompass this larger region from north TX to Mobile Bay.
Nonetheless, the development of very steep 0-3 km lapse rates (9 deg
C/km) by early to mid afternoon and high PW (1.75-2.0 inches) will
support scattered wind damage with the more intense downdrafts (most
likely and concentrated from east TX through southern MS).

...Northern Great Basin into the Snake Valley...
A mid-level vorticity max rotating northward around the western
periphery of the Four Corners upper high, will move into northern
NV/UT by late afternoon. Deep inverted-V profiles will develop by
mid afternoon with a dry sub-cloud layer featuring large surface temperature-dewpoint spreads. A linear cluster of storms is
expected to evolve and move north across the NV/UT/ID vicinity
during the late afternoon and early evening. Evaporatively cooled
downdrafts will be potentially capable of severe gusts 60-75 mph.

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 22 01:04:32 2026

ACUS01 KWNS 220104
SWODY1
SPC AC 220102

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0802 PM CDT Fri Aug 21 2026

Valid 220100Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
CENTRAL PLAINS AND MIDWEST...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail (some
2+ inches) and severe winds should continue over parts of the
central Plains into the Midwest this evening. Isolated damaging
winds also remain possible across portions of the Carolinas and
northern Gulf Coast states.

...Central Plains...
Evening water-vapor imagery showed a subtle mid-level perturbation
embedded within a broad corridor of northwesterly flow aloft
overspreading much of the central US. isolated storm development has
taken place along the western portions of a stalled front over
western NE. South of the front, very warm and humid conditions have
allowed for strong destabilization over much of the central Plains.
Robust deep-layer shear profiles are favorable for supercells with a
risk for large to very large hail, damaging gusts and perhaps a
tornado persisting this evening.

Additional development is possible along the stalled front farther
east late this evening with a forecast increase in the low-level
jet. Initial supercell structures are possible with hail and could
grow upscale into one ore more clusters with a risk for damaging
gusts through the overnight hours.

Isolated higher-based storms ongoing in eastern CO may persist for a
few hours this evening owing to very warm surface temperatures and
steep low/mid-level lapse rates. Located on the fringes of the more
robust buoyancy, isolated severe gusts or hail are possible as they
drift slowly southeastward.

...Midwest...
Beneath the upper trough over the Great Lakes, isolated to widely
scattered thunderstorms have developed ahead of the southward moving
cold front and remnant outflow boundary from southern WI into
eastern IA and northern IL. Large buoyancy (2000-3000 J/kg MLCAPE)
is in place within a warm and very moist air mass. Modest
enhancement of the mid-level flow is also supporting elongated
hodographs sufficient for storm organization. A mix of supercells
and multicells should continue for a few hours this evening with a
risk for hail and damaging gusts. A tornado or two also remains
possible where backed low-level flow is supporting stronger shear
across southeastern IA and northern IL.

...Carolinas...
Numerous thunderstorms developed along a frontal boundary across the
Carolinas this afternoon. These storms have gradually clustered and
produced numerous instance of wind damage. Given the extent of the
convection, much of the available buoyancy has been removed and much
of the convection has slowly weakened early this evening. Still,
some lingering instability along the coast should support storms for
a few hours this evening. High PWAT content and modest enhancement
of mid-level flow from a weak MCV may support some isolated damaging
wind gusts.

...Gulf Coast/Lower MS valley...
Numerous thunderstorms are ongoing ahead of a weak surface cold
front slowly moving southward along the lower MS Valley and central
Gulf Coast. Very warm temperatures within the seasonably humid air
mass are supporting moderate to large instability (2500-3500 J/kg of
MLCAPE). This will be more than sufficient to maintain strong to
severe storms within the ongoing clusters. Clustering and high PWAT
content (1.75-2.3 inches) will support isolated wind damage with the
more intense downdrafts for a few more hours this evening before
they eventually move offshore or weaken after sunset.

...Northern Great Basin...
Evening water-vapor imagery showed an upper trough moving from south
to north along the western periphery of a strong upper high centered
over the central Rockies. On the eastern periphery of this trough,
scattered thunderstorms are ongoing over parts of NV and western UT.
Monsoon moisture is supporting weak to moderate buoyancy atop steep
low-level lapse rates. The ongoing storms, with some clustering, are
expected to continue and move northward across the NV/UT/ID vicinity
through this evening. Deep inverted-V profiles and a dry sub-cloud
layers will favor strong downdrafts, potentially capable of severe
gusts 60-75 mph.

..Lyons.. 08/22/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 22 06:03:12 2026

ACUS01 KWNS 220602
SWODY1
SPC AC 220601

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0101 AM CDT Sat Aug 22 2026

Valid 221200Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER OHIO VALLEY...

...SUMMARY...
Scattered damaging gusts are likely across the Ohio Valley with more
isolated damaging wind potential extending westward into the Mid
Mississippi Valley and southern Plains this afternoon/evening.
Isolated hail and damaging winds are also possible over the Front
Range, Great Basin and parts of the northern Rockies.

...OH and TN Valleys...
An upper low initially over the western Great Lakes is forecast to
deepen as it moves southeastward today and tonight. A belt of
stronger mid-level flow behind the trough will move into parts of
the Plains and Midwest. A weak surface low and trailing cold front
will move southeastward across the Lakes and into the upper OH
Valley through the day. Ahead of the front, upper 60s to 70s F
surface dewpoints and filtered diurnal heating should allow for
moderate destabilization, sufficient for scattered to numerous
thunderstorms by early afternoon. Despite generally modest to weak
deep-layer shear, steepening of lower/mid-level lapse will support
stronger downdrafts within organized multicell clusters. With time,
some upscale growth into linear segments is also possible and would
also favor a risk for scattered damaging gusts. This appears most
likely across central/eastern OH and KY into western PA/WV.

Farther south, more isolated storm coverage is expected ahead of the
front from the western Carolina Piedmont to the TN Valley. Steep
low-level lapse rates and enhanced low and mid-level northwesterly
flow will still support some risk for isolated damaging gusts.

...Ozarks/Mid MS Valley...
A weak convectively augmented shortwave trough is forecast to move
from southeastern KS and southern MO into northern AR along western
portions of a weak surface front by midday. Ahead of these features,
a very warm and humid air mass will be in place, which should allow
substantial diurnal destabilization and eventual thunderstorm
development. Enhanced northwesterly flow may help organize a few
thunderstorm clusters as they spread eastward from the Ozarks into
the ArkLaTex and mid MS Valley. Damaging wind gusts and some hail
are possible.

...Front Range and adjacent High Plains...
Post-frontal upslope flow, aided by a weak short wave impulse on the
eastern periphery of the upper ridge will support thunderstorm
development along/east of the Laramie mountains through Colorado
Front Range this afternoon. On the fringes of the stronger northwest
flow aloft, deep-layer shear will be marginal for storm
organization. Steep mid-level lapse rates and moderate buoyancy
could support some hail with the stronger updrafts. Isolated
damaging gusts are also possible, especially with any more
persistent thunderstorm clusters.

...Southern Plains...
Very hot surface temperatures (100+ F) are likely across parts of
western North TX into southwestern and central OK this afternoon.
Low-level convergence near a thermally enhanced surface low and weak
front will aid high-based thunderstorm development late afternoon
into the early evening. Weak buoyancy atop the steep low-level lapse
rates and deep mixed layer will favor very strong downdrafts within
the high-based storms. Isolated severe gusts (possibly 65-75 mph
gusts) associated with microbursts are possible as convection is
forecast to move southward through the evening.

...Northern Rockies to the Great Basin....
An upper low along the western periphery of the substantial
mid-level ridge over the Southwest will migrate northward toward the international border as a belt of stronger mid-level flow
overspreads a plume of monsoon moisture from the Great Basin to the
Northern Rockies. Ascent from the upper wave and heating of the
modestly moist air mass should allow for weak destabilization and
scattered thunderstorm development. Steep lapse rates could support
isolated severe gusts.

Isolated hail is also possible with scattered thunderstorms from
eastern WA into the ID panhandle. Closer to the upper trough and
beneath strong mid-level flow, elongated hodographs may promote
organization with transient supercell structures. Cooler mid-level
temperatures could favor hail production despite modest overall
moisture.

..Lyons/Weinman.. 08/22/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 22 12:04:58 2026

ACUS01 KWNS 221204
SWODY1
SPC AC 221202

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0702 AM CDT Sat Aug 22 2026

Valid 221300Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY INTO THE CENTRAL APPALACHIANS...

...SUMMARY...
Thunderstorms capable of producing scattered damaging winds should
occur this afternoon across parts of the Ohio Valley into the
central Appalachians, with isolated damaging winds possible across
the lower Mississippi Valley to the southern Plains/Ozarks. Isolated
hail and damaging winds may also occur over parts of the central
Plains and northern Rockies into the Northwest.

...Ohio Valley into the Central Appalachians and Tennessee/Lower
Mississippi Valleys...
Upper troughing over Ontario and the Great Lakes will advance slowly
eastward today across the OH Valley/Midwest in tandem with a weak
surface cold front. Latest visible satellite imagery this morning
shows mostly clear skies present across the upper OH Valley
vicinity. While low-level moisture will remain fairly modest
(surface dewpoints generally in the 60s) and lapse rates aloft will
be near moist adiabatic, it still appears likely that around
1000-2000 J/kg of MLCAPE will develop ahead of the front by early
afternoon. A gradual increase in thunderstorm coverage and intensity
is expected, with 20-30 kt of effective bulk shear fostering enough
updraft organization for multicell clusters capable of producing
scattered damaging winds. These thunderstorms will spread eastward
from the upper OH Valley into the central Appalachians this
afternoon and evening before eventually weakening with eastward
extent. Isolated hail may occur with the stronger cores that
develop, but the poor mid-level lapse rates present may limit this
threat to some extent. There also appears to be some chance for
strong to locally severe thunderstorms to develop along/east of the
Blue Ridge Mountains this afternoon. If this occurs, then occasional
damaging winds would be the main threat with this activity.

There may be less thunderstorm coverage with southwestward extent
along/ahead of the front into the TN Valley/Mid-South, as
large-scale ascent will be weaker across these regions. Still, any
convection which can develop and be sustained will exist in a
favorable environment for damaging winds, with moderate to strong
instability and sufficient deep-layer shear present to support
multicell clusters.

...Southern/Central Plains into the Ozarks...
On the eastern periphery of upper ridging over the
Southwest/Rockies, thunderstorms have developed early this morning
across parts of the southern/central Plains. This convection is
being aided by modest low-level warm/moist advection, and multiple
weak mid-level disturbances moving through the northwesterly
mid-level flow across the Plains. While substantial MLCIN is
present, sufficient MUCAPE coupled with moderate to strong
deep-layer shear should continue to support updraft organization.
Isolated hail and strong to locally severe gusts may occur with the
more robust cores, and severe probabilities have been adjusted to
account for ongoing convection. Subsequent development of
thunderstorms this afternoon will be dependent on how this morning's
convection evolves, with some weakening possible as a modest
low-level jet gradually lessens over the next several hours. Still, redevelopment is forecast this afternoon along/south of a weak
front. Moderate to locally strong instability, very steep low-level
lapse rates, and moderate northwesterly deep-layer shear should
support some clustering/updraft organization. Occasional hail and
severe gusts may occur as thunderstorms spread southward across the
southern Plains/Ozarks this afternoon/evening.

A separate area of convection is forecast to develop this afternoon
along the Front Range/Laramie Mountains in a weak post-frontal
low-level upslope regime. While effective bulk shear should be
somewhat weaker across this region, a narrow corridor of greater
instability is forecast across the central High Plains. This may
support loosely organized multicells and marginal supercell
structures with an isolated severe hail/wind threat. This activity
should spread slowly southeastward off the higher terrain before
weakening this evening with the loss of daytime heating.

...Great Basin/Northern Rockies into the Northwest...
Upper ridging will remain prominent from the Southwest into the
northern Rockies/High Plains today. On the western periphery of this
ridging, an upper trough/low will move northward along/near the
coast of the Pacific Northwest. Enhanced south-southwesterly
mid-level flow will overspread parts of the Great Basin, northern
Rockies, and Northwest through the period, with the strongest winds
forecast over WA/OR. Low-level moisture remains fairly limited over
most of these regions, with somewhat greater surface dewpoints
present over parts of the Great Basin.

Diurnal heating should support modest destabilization and weak
instability from the northern Great Basin into the interior Pacific
Northwest and northern Rockies. Thunderstorms will develop this
afternoon as the large-scale ascent preceding the upper trough/low
overspreads these regions in tandem with orographic effects across
the higher terrain. Where low-level lapse rates can become
sufficiently steepened with a dry/well-mixed sub-cloud layer,
isolated severe/damaging winds may occur. The overall severe threat
should be limited by weak instability.

..Gleason/Broyles.. 08/22/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 22 16:32:32 2026

ACUS01 KWNS 221632
SWODY1
SPC AC 221630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Sat Aug 22 2026

Valid 221630Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY INTO THE CENTRAL APPALACHIANS AND THE MID SOUTH...

...SUMMARY...
Scattered severe thunderstorms are possible over parts of the Mid
South with 60 to 75 mph gusts being the primary hazard. Scattered
damaging winds are possible this afternoon across parts of the Ohio
Valley into the central Appalachians.

...Ohio Valley into the Central Appalachians and Tennessee/Lower
Mississippi Valleys...
An upper trough continues to dig southeast across the southwest
Great Lakes during the midday as a surface front advances slowly
east across the southern Great Lakes and OH Valley. Late morning
surface analysis places a moist plume (65 to 70 deg F surface
dewpoints) extending northeastward ahead of the front from the lower
OH Valley into northeast OH. Visible satellite imagery shows a
swelling cumulus field across the upper OH Valley where moderate
buoyancy has developed. A gradual increase in thunderstorm coverage
and intensity is expected, with 20-30 kt of effective bulk shear
fostering enough updraft organization for multicell clusters capable
of producing scattered damaging winds. See MCD #2081 for short-term
details. These thunderstorms will spread eastward from the upper OH
Valley into the central Appalachians this afternoon and evening
before eventually weakening with eastward extent. Isolated hail may
occur with the stronger cores that develop, but the poor mid-level
lapse rates present may limit this threat to some extent. There
also appears to be some chance for strong to locally severe
thunderstorms to develop along/east of the Blue Ridge Mountains this
afternoon. If this occurs, then occasional damaging winds would be
the main threat with this activity.

...Southern/Central Plains into the Mid South...
Satellite imagery late this morning shows a pair of convectively
enhanced mid-level vorticity maxima moving southeast over eastern
KS/OK on the eastern periphery of upper ridging centered over NM.
Weak thunderstorm activity continues to progress southeast over
eastern KS towards the Ozarks, where the airmass has heated near 90
deg F to the downstream of greater cloud cover. Surface analysis
this morning showed a reservoir of richer moisture (lower 70s deg F
surface dewpoints) south of a stalled west-east frontal zone.
Additional heating/destabilization ahead of the southeastward-moving thunderstorms and associated MCV will act to pre-condition the
environment to support a greater risk for severe gusts and wind
damage across parts of the Mid South this afternoon and early
evening. CAM model guidance both from a model core and time-lagged
ensemble, suggest the eventual development of a linear cluster
developing over the Ozarks and moving east-southeast into a
hot/unstable airmass featuring very steep 0-3 km lapse rates. Mid
to upper-level flow will tend to weaken with southeast extent, but
ample cloud-bearing shear for storm organization is evident. Have
upgraded a corridor from northern ARK into northern MS where
confidence is highest on an MCS developing and an associated risk
for severe gusts and wind damage.

Additional isolated storm development is expected later today across
parts of the southern Great Plains. Moderate to locally strong
instability, very steep low-level lapse rates, and moderate
northwesterly deep-layer shear should support some
clustering/updraft organization. Occasional hail and severe gusts
may occur as thunderstorms spread southward this afternoon/evening.

...Central High Plains/Front Range...
A separate area of convection is forecast to develop this afternoon
along the Front Range/Laramie Mountains in a weak post-frontal
low-level upslope regime. While effective bulk shear should be
somewhat weaker across this region, a narrow corridor of greater
instability is forecast across the central High Plains. This may
support loosely organized multicells and marginal supercells with an
isolated severe hail/wind threat.

...Great Basin/Northern Rockies into the Northwest...
Upper ridging will remain prominent from the Southwest into the
northern Rockies/High Plains today. On the western periphery of
this ridging, an upper trough/low will move northward along/near the
coast of the Pacific Northwest. Enhanced south-southwesterly
mid-level flow will overspread parts of the Great Basin, northern
Rockies, and Northwest through the period, with the strongest winds
forecast over WA/OR. Low-level moisture remains fairly limited over
most of these regions, with somewhat greater surface dewpoints
present over parts of the Great Basin.

Diurnal heating should support modest destabilization and weak
instability from the northern Great Basin into the interior Pacific
Northwest and northern Rockies. Thunderstorms will develop this
afternoon as the large-scale ascent preceding the upper trough/low
overspreads these regions in tandem with orographic effects across
the higher terrain. Where low-level lapse rates can become
sufficiently steepened with a dry/well-mixed sub-cloud layer,
isolated severe/damaging winds may occur. The overall severe threat
should be limited by weak instability.

..Smith/Chalmers.. 08/22/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sat Aug 22 19:58:36 2026

ACUS01 KWNS 221958
SWODY1
SPC AC 221956

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0256 PM CDT Sat Aug 22 2026

Valid 222000Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE OHIO VALLEY INTO THE CENTRAL APPALACHIANS...THE MID SOUTH...AND
THE SOUTHERN GREAT PLAINS...

...SUMMARY...
Scattered severe thunderstorms are possible over parts of the Mid
South and southern Great Plains with 60 to 75 mph gusts being the
primary hazard. Scattered damaging winds also remain possible this
afternoon across parts of the Ohio Valley into the central
Appalachians.

...20z Update...

...Southern Great Plains...
The primary change with this outlook update was an upgrade to a
Level 2/Slight risk for portions of northwest Texas and the Texas
Panhandle driven by the inclusion of 15% wind probabilities based on
the latest CAM and time-lagged ensemble guidance. The 5% wind
probability and CIG1 were similarly expanded across adjacent
portions of the southern Great Plains. See Mesoscale Discussion 2085
for additional short-term details.

...Mid Atlantic...
Isolated convective initiation is ongoing across portions of the
central Blue Ridge in far northwestern Virginia as of 1955 UTC.
Latest CAM/time-lagged ensemble guidance continues to suggest the
potential for some upscale growth/clustering of convection
downstream across northern Virginia. Some consideration was given to
a targeted upgrade to a Level 2/Slight risk (via the inclusion of a
15% wind probability) for this area; however, weak low-level flow
sampled by the Sterling (LWX) VWP and cooler downstream temperatures
in the upper-70s F lend uncertainty to the coverage of the resultant
severe risk and precluded an upgrade at this time. A locally greater
risk for damaging wind gusts could materialize should a cluster of
storms develop, however. See MCD 2083 for additional details.

Elsewhere, only minor adjustments were made based on recent convective/observational trends and the latest forecast guidance.
See the text below and Mesoscale Discussions 2084 and 2086 for
additional details.

..Chalmers/Moore.. 08/22/2026

.PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 22 2026/

...Ohio Valley into the Central Appalachians and Tennessee/Lower
Mississippi Valleys...
An upper trough continues to dig southeast across the southwest
Great Lakes during the midday as a surface front advances slowly
east across the southern Great Lakes and OH Valley. Late morning
surface analysis places a moist plume (65 to 70 deg F surface
dewpoints) extending northeastward ahead of the front from the lower
OH Valley into northeast OH. Visible satellite imagery shows a
swelling cumulus field across the upper OH Valley where moderate
buoyancy has developed. A gradual increase in thunderstorm coverage
and intensity is expected, with 20-30 kt of effective bulk shear
fostering enough updraft organization for multicell clusters capable
of producing scattered damaging winds. See MCD #2081 for short-term
details. These thunderstorms will spread eastward from the upper OH
Valley into the central Appalachians this afternoon and evening
before eventually weakening with eastward extent. Isolated hail may
occur with the stronger cores that develop, but the poor mid-level
lapse rates present may limit this threat to some extent. There
also appears to be some chance for strong to locally severe
thunderstorms to develop along/east of the Blue Ridge Mountains this
afternoon. If this occurs, then occasional damaging winds would be
the main threat with this activity.

...Southern/Central Plains into the Mid South...
Satellite imagery late this morning shows a pair of convectively
enhanced mid-level vorticity maxima moving southeast over eastern
KS/OK on the eastern periphery of upper ridging centered over NM.
Weak thunderstorm activity continues to progress southeast over
eastern KS towards the Ozarks, where the airmass has heated near 90
deg F to the downstream of greater cloud cover. Surface analysis
this morning showed a reservoir of richer moisture (lower 70s deg F
surface dewpoints) south of a stalled west-east frontal zone.
Additional heating/destabilization ahead of the southeastward-moving thunderstorms and associated MCV will act to pre-condition the
environment to support a greater risk for severe gusts and wind
damage across parts of the Mid South this afternoon and early
evening. CAM model guidance both from a model core and time-lagged
ensemble, suggest the eventual development of a linear cluster
developing over the Ozarks and moving east-southeast into a
hot/unstable airmass featuring very steep 0-3 km lapse rates. Mid
to upper-level flow will tend to weaken with southeast extent, but
ample cloud-bearing shear for storm organization is evident. Have
upgraded a corridor from northern ARK into northern MS where
confidence is highest on an MCS developing and an associated risk
for severe gusts and wind damage.

Additional isolated storm development is expected later today across
parts of the southern Great Plains. Moderate to locally strong
instability, very steep low-level lapse rates, and moderate
northwesterly deep-layer shear should support some
clustering/updraft organization. Occasional hail and severe gusts
may occur as thunderstorms spread southward this afternoon/evening.

...Central High Plains/Front Range...
A separate area of convection is forecast to develop this afternoon
along the Front Range/Laramie Mountains in a weak post-frontal
low-level upslope regime. While effective bulk shear should be
somewhat weaker across this region, a narrow corridor of greater
instability is forecast across the central High Plains. This may
support loosely organized multicells and marginal supercells with an
isolated severe hail/wind threat.

...Great Basin/Northern Rockies into the Northwest...
Upper ridging will remain prominent from the Southwest into the
northern Rockies/High Plains today. On the western periphery of
this ridging, an upper trough/low will move northward along/near the
coast of the Pacific Northwest. Enhanced south-southwesterly
mid-level flow will overspread parts of the Great Basin, northern
Rockies, and Northwest through the period, with the strongest winds
forecast over WA/OR. Low-level moisture remains fairly limited over
most of these regions, with somewhat greater surface dewpoints
present over parts of the Great Basin.

Diurnal heating should support modest destabilization and weak
instability from the northern Great Basin into the interior Pacific
Northwest and northern Rockies. Thunderstorms will develop this
afternoon as the large-scale ascent preceding the upper trough/low
overspreads these regions in tandem with orographic effects across
the higher terrain. Where low-level lapse rates can become
sufficiently steepened with a dry/well-mixed sub-cloud layer,
isolated severe/damaging winds may occur. The overall severe threat
should be limited by weak instability.

$$

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From COD Weather Processor @1:2320/107 to All on Sun Aug 23 01:02:20 2026

ACUS01 KWNS 230102
SWODY1
SPC AC 230100

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Sat Aug 22 2026

Valid 230100Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
SOUTHEAST ARKANSAS...NORTHERN MISSISSIPPI...AND EXTREME NORTHWEST
ALABAMA...

...SUMMARY...
Scattered severe thunderstorms will be possible for another couple
hours across portions of the lower Mississippi Valley before
thunderstorm intensity wanes later this evening and overnight.

... 01Z Update ...

Thunderstorm intensity continues to wane across much of the United
States this evening. The most intense thunderstorms continue to be a
cluster of southeast moving thunderstorms across the lower
Mississippi Valley. Here, strong instability will maintain a hail
and wind threat for a couple more hours before weakening with the
increasing boundary layer stability.

Elsewhere, a few sporadic damaging wind gusts will be possible with
a weakening line of storms across central Pennsylvania south into
southern Virginia over the next couple of hours as well as across
portions of the southern High Plains where a linear MCS continues to
push south and west.

Across portions of the Nebraska Panhandle northwest into eastern
Wyoming and western South Dakota, strong vertical shear and 2000
J/kg MUCAPE will maintain support for a few large hail stones and a
couple of marginally severe wind gusts.

A cluster of storms across south-central Colorado will be capable of
marginally severe hail and wind gusts for another one or two hours
before weakening with the loss of diurnal heating.

Across the west, strong thunderstorm wind gusts will be possible
from northern Utah northward toward far southwest Montana. These
high-based storms will be capable of sporadic downbursts capable of
strong erratic winds.

Lastly, a low probability of marginally severe hail and wind gusts
will remain possible across northern Washington this evening as a
strong mid-level just streak continues to lift northeast into
Canada.

..Marsh.. 08/23/2026

$$

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* Origin: capitolcityonline.net * KY, USA (1:2320/107)

From COD Weather Processor @1:2320/107 to All on Sun Aug 23 06:12:00 2026

ACUS01 KWNS 230611
SWODY1
SPC AC 230609

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0109 AM CDT Sun Aug 23 2026

Valid 231200Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS...MUCH OF CENTRAL MONTANA...AND PORTIONS OF THE
EASTERN GREAT BASIN...

...SUMMARY...
Strong-to-severe thunderstorms capable of large hail and damaging
winds will be possible across portions of the northern Rockies and
northern Plains. Additional severe thunderstorms capable of damaging
winds will be possible across portions of northern Utah.

... Synopsis ...

A sub-tropical mid-level ridge will remain in place across much of
the West on Sunday, with a large-scale trough taking shape across
much of the East. A seasonably strong short-wave trough will crest
the ridge over southern Canada, with an attendant jet streak in its
basal region moving across Montana. Broadly northwest mid-level flow
will exist from the northern Plains east toward the Appalachians,
between the western ridge and eastern trough.

... Intermountain West ...

A well-mixed boundary layer will develop during the afternoon as
cooler mid-level temperatures associated with the approaching
short-wave trough overspread the northern Rockies. Scattered
thunderstorms should develop during the early to mid-afternoon
within an environment with steepening mid-level lapse rates.
Effective shear on the order of 30-40 knots will support multicell
clusters and transient supercell structures capable of producing
large hail and damaging wind gusts.

Farther south, multicell clusters should develop across eastern
Nevada and western Utah during the late afternoon. Modest mid-level
flow on the north side of the subtropical ridge, coupled with steep
low-level lapse rates (inverted-V profiles) should support efficient
downward momentum transfer with any sustained thunderstorm updraft.

... Northern Plains south into the Central High Plains ...

A plume of steep mid-level lapse rates will advect out from the
northern Rockies and overspread a moistening warm sector. The result
will be afternoon MUCAPE values between 2000-3000 J/kg. Although
vertical shear is not overly strong, forecast soundings/hodographs
suggest enough shear to support multicells and transient supercell
structures. Large hail will be possible with these initial
thunderstorms. With time, congealing outflows should support some
potential for upscale growth toward an MCS. Steep lapse rates will
support severe winds (some significant) with any organized
thunderstorm cluster.

... Northeast US ...

Early morning convection should dissipate enough to support at least
filtered sunshine during the late morning and early afternoon. This
will support temperatures warming into the 70Fs to perhaps low 80Fs.
This, when combined with upper 50Fs to low 60Fs dewpoints will
support between 500-1000 J/kg MUCAPE during the afternoon. Vertical
ascent downstream of the eastern trough will support clusters of
thunderstorms across the region. Modest mid-level lapse rates should
limit a more robust hail threat, but the degree of ascent and
instability will support a marginal risk of severe hail and damaging
wind.

... Northern Gulf Coast toward the Coastal Carolinas ...

Strong diurnal heating of a moist boundary layer (dewpoint
temperatures in the 70Fs) should support MUCAPE values between
3000-4000 J/kg during the afternoon. High precipitable water values
will support water-loaded updrafts capable of producing isolated
damaging downbursts with the strongest cells.

... Southern Arizona ...

Seasonably strong southeasterly mid-level flow will develop along
the periphery of the mid-upper-level ridge. This enhanced flow will
overspread a deeply mixed boundary layer (inverted-V) during the
afternoon. In spite of the deeply mixed boundary layer, precipitable
water values in excess of 1" will exist across the area during the
late afternoon. This will support at least isolated thunderstorm
clusters capable of producing damaging wind gusts.

... Southeast Kansas, Northeast Oklahoma, Southwest Missouri, and
Northwest Arkansas ...

A low amplitude mid-level trough will move southeast across the
Central US on Sunday, within the broader northwest flow. Although an
isolated thunderstorm cannot be ruled out with this feature during
the afternoon, the more likely scenario is the environment across
Kansas and Missouri remains capped during the afternoon.

By late evening, the mid-level trough/jet streak should be across
southern Missouri or northeast Arkansas, placing northeast Oklahoma
and southeast Kansas in the right entrance region of the mid-level
jet. Guidance is pretty confident in developing a strong low-level
jet across the southern Plains in response to this mid-level jet.
The result will be increasing warm-air advection/isentropic ascent
during the overnight. This will lead to scattered thunderstorm
development, with movement off to the east-southeast. Mid-level
lapse rates should only be on the order of 6.5 C/km, but
cloud-bearing shear around 30-40 knots should support strong
updrafts. DCAPE values between 500-1000 J/kg will support at least
marginally severe downbursts capable of wind damage.

..Marsh/Weinman.. 08/23/2026

$$

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--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)

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