ACUS11 KWNS 040149
SWOMCD
SPC MCD 040149=20
ILZ000-MOZ000-040345-

Mesoscale Discussion 0637
NWS Storm Prediction Center Norman OK
0849 PM CDT Sun May 03 2026

Areas affected...portions of western and central Missouri into
Illinois

Concerning...Severe potential...Watch unlikely=20

Valid 040149Z - 040345Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated to scattered high-based storms are expected to
develop this evening across parts of MO and IL. Very steep mid-level
lapse rates and moderate vertical shear could promote a few strong
to severe storms with hail and damaging gusts. A WW is unlikely.

DISCUSSION...As of 0145 UTC, regional WV imagery showed mid-level
ascent associated with an upper-level shortwave trough that was
observed moving out of the northern Plains/Rockies into parts of the
central US near a slow-moving cold front. As mid-level ascent
continues eastward, it will overspread a warm and modestly moist air
mass along and south of the front. Temperatures in the 70s with
dewpoints in the 40s and 50s amid mid-level lapse rates of 8.5-9
C/km are supporting around 1000 J/kg of MUCAPE (TOP RAOB). Strong
mid-level flow associated with the trough is also in place with
deep-layer shear of 40-50 kt.

Night time microphysics and IR imagery showed deepening ACCAS across north-central MO and west-central IL associated with the cold front
and increased 850 mb low-level jet. Observational trends and CAM
guidance shows initially isolated high-based thunderstorm
development will likely increase in coverage this evening. Despite
limited buoyancy, the very steep lapse rates and strong vertical
shear may promote some organized supercell structures capable of
hail or damaging gusts.

Given the limited instability and more isolated nature of the severe
risk, a WW appears unlikely this evening. However convective trends
will be monitored.

..Lyons/Hart.. 05/04/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4jM7gdNlw72KwmLG5TWbgrZ34knzupfcPUQs9cTotEyGIisAVoBFnNaxE4JsKElJPlaETDFnl= W4JPqTHBbCVxkLMD_w$ for graphic product...

ATTN...WFO...PAH...ILX...LSX...DVN...SGF...EAX...

LAT...LON 38069196 38169303 38759402 39209411 39819384 40259236
40399100 40208988 39938866 39308793 38788811 38398844
38088900 38058977 38009074 38069196=20

MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


=3D =3D =3D
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