Storm Prediction Center Mesoscale Discussion 794

   Mesoscale Discussion 0794
   NWS Storm Prediction Center Norman OK
   0322 PM CDT Thu May 15 2025

   Areas affected...Parts of central and northern Illinois

   Concerning...Severe potential...Watch possible 

   Valid 152022Z - 152215Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Large to very large hail and severe winds will be possible
   with supercells that can develop later this afternoon. Watch timing
   is uncertain but is possible later this afternoon.

   DISCUSSION...Cumulus are developing along an eastward moving dryline
   near the Mississippi River. Ahead of this boundary, a strongly
   unstable airmass is in place (low 90s F temperatures and mid 60s to
   low 70s F dewpoints). With the strongest mid-level ascent to the
   northwest of the region, timing of storm initiation as well as storm
   coverage are uncertain. However, given the lack of MLCIN, a isolated
   to widely scattered development appears possible later this
   afternoon. 45-55 kts of effective shear will support supercells. The
   primary hazards will be large to very large hail and severe winds.
   The tornado threat is expected to be less than farther north given
   the slightly veered low-level winds and more sizable
   temperature/dewpoint spreads at the surface.

   ..Wendt/Mosier.. 05/15/2025

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

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

   LAT...LON   39418987 41039031 41568999 41998852 42058826 41548812
               40218818 39388856 39158871 39048891 39418987 

   MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN