Storm Prediction Center Mesoscale Discussion 299

   Mesoscale Discussion 0299
   NWS Storm Prediction Center Norman OK
   1243 PM CDT Sun Mar 30 2025

   Areas affected...Portions of northeast Illinois...northern
   Indiana...southwest Lower Michigan

   Concerning...Severe potential...Watch likely 

   Valid 301743Z - 301945Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Damaging winds will be the primary hazard with storms this
   afternoon. Isolated large hail may also occur. The tornado threat is
   less certain, but a few line-embedded circulations do appear
   possible.

   DISCUSSION...Temperatures in northeast Illinois into northern
   Indiana have risen into the low/mid 70s F. Cumulus along the cold
   front has deepened in northeast Illinois and storms appear likely to
   initiate as the shortwave trough moves through the region. In
   addition, some portion of the activity in central Illinois will move
   northeastward into parts of northern Indiana.

   Destabilization should continue through the afternoon, particularly
   in northern Indiana into southern Lower Michigan. MLCAPE in
   northeast Illinois is 500-750 J/kg and it is not clear how much more
   buoyancy will develop before the fast moving storms move through.
   The greatest risk will be strong/damaging wind gusts with what is
   expected to be one or more linear segments. Large hail is possible,
   but should be more spatially limited given storm mode. The tornado
   threat is less clear this far north. Low-level winds are veered and
   effective SRH values from objective mesoanalysis and regional VAD
   profiles is not large. However, the QLCS tornado threat is nonzero
   as line-embedded circulations are certainly possible. A watch is
   likely this afternoon.

   ..Wendt/Smith.. 03/30/2025

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

   ATTN...WFO...IWX...GRR...LOT...ILX...

   LAT...LON   40848645 40448774 40378826 40878876 41708893 41928887
               42328804 42768640 42598582 41918550 40948614 40848645 

   MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN