Storm Prediction Center Mesoscale Discussion 1162

   Mesoscale Discussion 1162
   NWS Storm Prediction Center Norman OK
   0721 AM CDT Wed Jun 17 2026

   Areas affected...Eastern Iowa...Far Northeast Missouri...Central and
   Northern Illinois...Far Western Indiana

   Concerning...Severe potential...Watch likely 

   Valid 171221Z - 171415Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Severe wind gusts potentially above 80 mph, tornadoes and
   isolated large hail will be likely this morning from eastern Iowa
   southeastward across northwest and and central Illinois. Weather
   watch issuance is expected along this corridor.

   DISCUSSION...Radar imagery shows a well-developed severe bowing line
   segment ongoing over eastern Iowa. This line will move quickly
   southeastward into northwestern and central Illinois this morning,
   where damaging wind gusts will be likely. The line is located near
   the nose of a strong low-level jet, which will shift eastward into
   western Illinois over the next few hours. In response, the bowing
   line segment is expected to become very organized and will lay down
   a swath of wind-damage across northwest and central Illinois, where
   wind gusts in the 80 to 100 mph range will be possible. In addition,
   RAP forecast soundings increase 0-3 km storm-relative helicity into
   the 400 to 450 m2/s2 range across western and central Illinois by
   mid morning, suggesting that a tornado threat will develop with the
   bowing line segment. Tornadoes will be possible near the apex of the
   bow, and with any supercell embedded in the line. Isolated large to
   very hail could also occur within the more intense cores of
   supercells.

   ..Broyles/Guyer.. 06/17/2026

   ...Please see www.spc.noaa.gov for graphic product...

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

   LAT...LON   39308747 39048810 39088873 39428972 39949092 40519207
               40839246 41249260 41589250 41899226 42249172 42339108
               41868958 41568894 40998785 40578738 40198717 39688722
               39308747 

   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