ACUS11 KWNS 300038
SWOMCD
SPC MCD 300038=20
INZ000-KYZ000-ILZ000-300245-

Mesoscale Discussion 1348
NWS Storm Prediction Center Norman OK
0738 PM CDT Thu Jun 29 2023

Areas affected...Parts of southern IL...southern IN...and western KY

Concerning...Severe Thunderstorm Watch 420...

Valid 300038Z - 300245Z

The severe weather threat for Severe Thunderstorm Watch 420
continues.

SUMMARY...Risk of large hail and perhaps locally severe gusts
continues across parts of southern IL and IN this evening, and could
persist for another few hours. A new watch issuance is not currently
expected upon the expiration of WWs 417 and 420.

DISCUSSION...Latest water vapor imagery depicts a low-amplitude
shortwave impulse overspreading parts of central IL/IN this evening
-- accompanied by 60-70 kt of midlevel flow (per regional VWP data).
A strengthening low-level jet impinging on a remnant cold pool over
southern IL/IN is favoring regenerative convection along/atop the outflow-cooled air. While surface observations and RAP forecast
soundings suggest this activity should remain elevated given the
increased boundary-layer stability, 70-80 kt of effective shear is
still favoring semi-discrete supercells capable of large hail. And,
given the potential for strong midlevel mesocyclones which could
locally modify the near-storm environment, locally damaging gusts
cannot be entirely ruled out. With a reservoir of elevated
instability and the aforementioned deep-layer shear, the severe
threat could continue for a few more hours. Currently, a new watch
issuance is not expected upon the expiration of Severe Thunderstorm
Watches 417 and 420 given the limited areal coverage and uncertainty
on convective intensity, though convective trends will be monitored.

..Weinman/Hart.. 06/30/2023

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!5YxNnDjNpkFUunTHJknbWtFJHcv9t224j6wxemmHMzfN014DgufdtAfcd9aj15ha7u0SalfFv= Oy-zdzAPbSQYfKO8X0$ for graphic product...

ATTN...WFO...LMK...IND...PAH...ILX...LSX...

LAT...LON 37878793 38348868 38598877 38788873 38998847 39048820
38738730 38538675 38238631 37938618 37378645 37338692
37488739 37878793=20


=3D =3D =3D
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