ACUS11 KWNS 172101
SWOMCD
SPC MCD 172100=20
INZ000-ILZ000-MOZ000-172200-

Mesoscale Discussion 1167
NWS Storm Prediction Center Norman OK
0400 PM CDT Wed Jun 17 2026

Areas affected...eastern Missouri...central Illinois...western
Indiana

Concerning...Tornado Watch 342...

Valid 172100Z - 172200Z

The severe weather threat for Tornado Watch 342 continues.

SUMMARY...Tornado threat continues within WW342. A corridor of
increasing tornado potential may emerge across central Illinois
during the next couple of hours.

DISCUSSION...Air mass recovery is ongoing across central Illinois in
the wake of morning convection south of a boundary of strong
differential heating. Dew points in the upper 60s to 70s are
shifting northward back into central Illinois with temperatures
warming in the 80s. Pressure falls are maximized across this region,
with strong low-level southerly flow with the strong mass response.
North of the boundary, elevated supercell structures have developed.
Within this region STP is approaching 3-5 with effective SRH around
700 m2/s2 in the 20z RAOB from ILX. Should a supercell be able to
become surface based tornado potential will rapidly increase.

Additional watches will need to extend downstream into portions of central/southern Indiana in the next hour.

..Thornton.. 06/17/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!5S-OWyFSMP6UJ2UV478EA3PWsGbV-AWDOx3R8w768N9__w9dGw9fo0LMIzGU8ra6IemjesL6q= 5KHGdec2HKF2JhL-Ww$ for graphic product...

ATTN...WFO...IND...LOT...ILX...LSX...DVN...

LAT...LON 39589214 40129157 40369097 40519013 40528888 40388739
40078709 39768696 39278709 38738725 38678744 38658852
38578977 38479092 38499143 38669172 38869191 39119207
39589214=20

MOST PROBABLE PEAK TORNADO INTENSITY...140-170 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN


=3D =3D =3D
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