ACUS11 KWNS 211811
SWOMCD
SPC MCD 211810=20
OKZ000-KSZ000-TXZ000-COZ000-NMZ000-212015-

Mesoscale Discussion 0812
NWS Storm Prediction Center Norman OK
0110 PM CDT Thu May 21 2026

Areas affected...portions of southeastern Colorado Northern New
Mexico and the western Texas/Oklahoma Panhandles

Concerning...Severe potential...Watch possible=20

Valid 211810Z - 212015Z

Probability of Watch Issuance...40 percent

SUMMARY...Initial high-based updrafts developing over the Sangre De
Cristos and Raton Mesa should gradually intensify as the atmosphere
continues to destabilize. Isolated supercells with hail are the
primary hazard. Uncertainty remains regarding storm coverage and
intensity but a watch is possible.

DISCUSSION...As of 1810 UTC, regional visible imagery and surface
observations showed initial updrafts developing over the higher
terrain of southeastern CO and northern NM. Supported by strong
diurnal heating amid a broad upslope flow regime south a broad upper
low over the northern Rockies, these initial convective cells are
very high-based with T/TD spreads of 20-30 degrees suggesting they
are rooted near the top of a well mixed and weakly unstable boundary
layer. Farther east, more substantial surface moisture is in place
with dewpoints in the mid 40s to mid 50s F. As these incipient
updrafts are advected off the higher terrain by 30-40 kt of
west/southwesterly flow aloft, they will encounter more robust
destabilization with SPC mesoanalysis showing 1000-1500 J/kg of
MUCAPE present. This should allow for gradual intensification with time/eastward extent.

While deep-layer flow is not overly strong, VADs and area RAP
sounding show sufficient bulk shear for supercells and organized
multicells. With steep low and mid-level lapse rates, hail is
possible with the stronger storms. Some damaging wind threat may
also evolve given the warming boundary layer.

The exact timing and convective evolution remains unclear this
afternoon as overall forcing for ascent is weaker than farther
north. Recent CAM guidance shows these initial storms consolidating
into a couple supercells before drifting east/southeast this
afternoon. This should favor a general increase in the severe risk
with time. However, the more limited thermodynamic and kinematic
environment does cast some uncertainty on the spatial extent and
intensity of the convection this afternoon. Given all this,
conditions are being monitored for a possible WW this afternoon.

..Lyons/Hart.. 05/21/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-PznPiRuMUnRcq2TMyI7hPkglSRtgrw6UzjwH3g4AMtRO10kOABOXF-J65RRVesUlOoc_-COw= 5lqrPAlQz36Q0qC5gI$ for graphic product...

ATTN...WFO...DDC...GLD...AMA...PUB...BOU...ABQ...

LAT...LON 38590293 37880223 36970199 36290212 35740247 35470400
35460474 35690517 37880505 38550521 38800428 38750359
38590293=20

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/107)