Subj : MESO: Mesoscale Discussion 0309
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Wed Mar 22 2023 23:32:14

ACUS11 KWNS 222332
SWOMCD
SPC MCD 222331=20
ILZ000-MOZ000-230130-

Mesoscale Discussion 0309
NWS Storm Prediction Center Norman OK
0631 PM CDT Wed Mar 22 2023

Areas affected...north central Missouri into central Illinois

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

Valid 222331Z - 230130Z

Probability of Watch Issuance...20 percent

SUMMARY...Scattered strong thunderstorms may begin to develop by
8-10 PM CDT, with a few posing a risk for large hail before storms
become more widespread while spreading east-northeast of the
Mississippi River later this evening.

DISCUSSION...Deepening convection is evident within a narrow
corridor just to the cool side of a quasi-stationary to slowly
southward advancing near-surface frontal zone (currently still to
the north of the Sedalia and Columbia vicinities east-northeastward
toward Springfield, IL). Low-level moisture within this zone may be
contributing to most unstable CAPE up to around 1500 J/kg, beneath
modestly steep mid-level lapse rates.  However, thermodynamic
profiles include a relatively warm/capping layer between 850-700 mb,
beneath building large-scale mid/upper ridging east of the southern
Rockies into the Appalachians.

There does appear to be a weak short wave perturbation progressing
into the crest of this mid-level ridging, across and east-northeast
of the lower Missouri Valley vicinity.  And model output has been
suggestive that associated forcing for ascent and cooling through
the capping inversion may allow the initiation of scattered
thunderstorms as early as 01-03Z.  This may be aided by radiational
cloud top cooling after dark.

As storms initiate, and before convection becomes increasingly
widespread, strong vertical shear within the convective layer may
contribute to a couple of supercell structures posing a risk to
produce large hail.  Despite the proximity to the frontal zone,
given the rather rapid/sharp cooling to the north of the frontal
zone, the potential for strong surface gusts appears limited, even
as west-southwesterly 850 mb flow strengthens in excess of 40 kt by
late evening.

...Kerr.. 03/22/2023

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!84btfRdOuReSGsBAb2xkTMU_Qyc5jygJGz7atj-nTwwoAf-4RMWFVie2wfStXV7_b3NJXNQa0=
48xvK5HzmCHtMg1Cs8$  for graphic product...

ATTN...WFO...LOT...ILX...LSX...DVN...EAX...

LAT...LON   39809338 40608970 40418837 39898931 39539086 39129257
            39029413 39809338=20


=3D =3D =3D
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