ACUS11 KWNS 250107
SWOMCD
SPC MCD 250106=20
INZ000-ILZ000-250230-

Mesoscale Discussion 1303
NWS Storm Prediction Center Norman OK
0806 PM CDT Wed Jun 24 2026

Areas affected...portions of northeastern Illinois into northwestern
Indiana

Concerning...Severe Thunderstorm Watch 387...

Valid 250106Z - 250230Z

The severe weather threat for Severe Thunderstorm Watch 387
continues.

SUMMARY...The severe threat will gradually diminish over the next
1-2 hours. Isolated large hail, damaging wind gusts, and perhaps a
brief tornado remain possible in the meantime.

DISCUSSION...Scattered strong to severe thunderstorms remain ongoing
across portions of northeastern Illinois and are beginning to spread
into northwestern Indiana as of 0100 UTC. A mixed storm mode of
supercells and clusters has produced sporadic large hail and
damaging wind reports over the past 1-2 hours, and this threat is
expected to persist east-southeastward into far northwestern
Indiana, with isolated large hail, damaging wind gusts, and perhaps
a brief tornado remaining possible. Objective analysis indicates
that available buoyancy decreases rapidly with eastward extent,
however. Coupled with the onset of low-level nocturnal
cooling/stabilization and the eastward progression of the attendant
mid-level shortwave trough, this will result in a gradually
diminishing severe threat over the next couple of hours. A local
watch extension could be needed should a stronger storm or two
persist through the expiration time of Severe Thunderstorm Watch 387
at 0300 UTC, but additional watch issuance is not anticipated at
this time.

..Chalmers.. 06/25/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!5x9w7IjwtYpiz6zjy3HI4RA16T7CiouzXxVk5znVJ8KZ4KnQ4HmphZzb9-Ku7CCGvX7lFgpU5= JKhHeIIOiPUSbSvPSQ$ for graphic product...

ATTN...WFO...IWX...LOT...DVN...

LAT...LON 42278925 42438890 42418821 42168719 41788692 41298688
40878710 40708750 40778834 41138912 41808957 42098950
42278925=20

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


=3D =3D =3D
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