Storm Prediction Center Mesoscale Discussion 1409

   Mesoscale Discussion 1409
   NWS Storm Prediction Center Norman OK
   0126 PM CDT Tue Jun 25 2024

   Areas affected...eastern Illinois and southwest Indiana

   Concerning...Severe Thunderstorm Watch 457...

   Valid 251826Z - 252000Z

   The severe weather threat for Severe Thunderstorm Watch 457
   continues.

   SUMMARY...The greatest damaging wind threat will exist across
   eastern Illinois and southwest Indiana this afternoon.

   DISCUSSION...Fast moving outflow has far outpaced convection across
   much of Illinois. However, across the eastern portion of the state,
   the shear vector is more favorably aligned to the outflow boundary
   and thus, more robust convection has developed. These storms are
   also on the northeast periphery of the more unstable airmass with
   2000-3000 J/kg MLCAPE. From these storms southeastward (aligned with
   the deep layer shear vector) expect the strongest storms this
   afternoon. Damaging wind gusts will be the primary threat although
   some marginally large hail may be possible, particularly for the
   next hour while storms remain more cellular with some supercell
   structures.

   ..Bentley/Hart.. 06/25/2024

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

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

   LAT...LON   38518850 39138868 39468865 39658850 39868809 39838688
               39288642 38748623 38318666 38238762 38518850