Subj : MESO: Mesoscale Discussion 1252
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Jun 25 2023 16:57:16

ACUS11 KWNS 251657
SWOMCD
SPC MCD 251656=20
OHZ000-MIZ000-INZ000-251900-

Mesoscale Discussion 1252
NWS Storm Prediction Center Norman OK
1156 AM CDT Sun Jun 25 2023

Areas affected...Portions of far southern Lower
MI...northern/central IN...and far northwestern OH

Concerning...Severe potential...Tornado Watch likely=20

Valid 251656Z - 251900Z

Probability of Watch Issuance...80 percent

SUMMARY...The threat for a few tornadoes, very large hail, and
severe/damaging winds will increase this afternoon. Tornado Watch
issuance is likely.

DISCUSSION...Convection has quickly increased across far
northeastern IL and southern Lake Michigan (near/just east of
Chicago) as large-scale ascent preceding an upper trough/low across
the Upper Midwest impinges on a rapidly destabilizing warm sector.
Additional supercells will likely develop over the next couple of
hours southward into parts of western/central IN along and just
ahead of an eastward-advancing cold front. Airmass recovery in the
wake of earlier convection is already well underway, with upwards of
1500-2000 J/kg of MLCAPE present per recent mesoanalysis estimates.
A 50+ kt mid-level westerly jet attendant to the upper trough/low
will overspread the OH Valley through the afternoon, aiding in
strong (40-50+ kt) deep-layer shear and potential for supercells.

Given the rather favorable thermodynamic and kinematic environment,
along with rather steep mid-level lapse rates, very large hail (2+
inches) may occur with multiple supercells that develop initially.
As a west-southwesterly low-level jet modestly strengthens through
the rest of the day, low-level shear across IN and vicinity should
likely increase. A corresponding risk for a few tornadoes should
also exist with any supercells that can remain discrete, as
effective SRH around 100-200 m2/s2 becomes common later this
afternoon. The damaging wind threat may tend to remain isolated
while a discrete convective mode is maintained. But, scattered
severe/damaging winds appear increasingly likely with eastward
extent across IN as convection should grow upscale into one or more
bowing clusters.

...Gleason/Grams.. 06/25/2023

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!_WIY_kfISHAeITUQZVsloI-RNVlsTQNJNO80nRg5-Jek18m4BhH_lsR-b4WHXkK78GBT__qTK=
5JfrJ8Uio_p5jTrfZQ$  for graphic product...

ATTN...WFO...IWX...IND...

LAT...LON   40658672 41498689 41948653 41988539 41848459 41268457
            40188518 39018576 39178685 40658672=20


=3D =3D =3D
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