Storm Prediction Center Mesoscale Discussion 305

   Mesoscale Discussion 0305
   NWS Storm Prediction Center Norman OK
   1055 AM CDT Tue Mar 31 2026

   Areas affected...parts of southern Lower Michigan...east central
   Illinois...northern and central Indiana...northwestern Ohio

   Concerning...Severe Thunderstorm Watch 78...

   Valid 311555Z - 311800Z

   The severe weather threat for Severe Thunderstorm Watch 78
   continues.

   SUMMARY...Thunderstorms may gradually begin to intensify and
   consolidate into an organizing cluster with increasing risk for
   producing potentially damaging wind gusts through 3-4 PM EDT. 
   Additional severe weather watches may be needed and trends are being
   monitored for this possibility.

   DISCUSSION...Forcing for ascent downstream of a low amplitude short
   wave trough, along the southern fringe of the stronger westerlies,
   has been supporting an ongoing area of convective development
   overspreading northern/central Illinois and adjacent portions of the
   Midwest.  This has included stronger embedded thunderstorms which
   have been producing small to occasionally marginal severe hail.  

   As this develops eastward, insolation downstream is contributing to
   boundary-layer destabilization of a modestly moist boundary
   characterized by mid 50s+ F surface dew points, but with a tongue of
   near 60F+ dew points emanating from the lower Mississippi Valley now
   advecting across and northeast of southeastern Illinois and southern
   central Indiana.  As this develops toward the lower Great Lakes
   vicinity through 19-20Z, upstream thunderstorm activity may
   gradually begin to intensify, grow upscale and organize in the
   presence of modestly sheared 30-40 kt westerly deep-layer mean flow.
    This may slowly be accompanied by increasing potential to produce
   strong to severe surface gusts, in addition to occasional severe
   hail.

   ..Kerr.. 03/31/2026

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

   ATTN...WFO...CLE...ILN...DTX...IWX...IND...LOT...ILX...

   LAT...LON   41878347 41298279 40088354 39258667 39548851 40408788
               41078654 42028576 41878347 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN