Mesoscale Discussion 1468
   NWS Storm Prediction Center Norman OK
   0712 PM CDT Tue Aug 10 2021

   Areas affected...Western lower Michigan into northern Indiana and
   far northwestern Ohio

   Concerning...Severe potential...Watch likely 

   Valid 110012Z - 110115Z

   Probability of Watch Issuance...95 percent

   SUMMARY...A line of severe thunderstorms is expected to cross lake
   Michigan and northern Indiana this evening. Damaging wind gusts
   appear likely and a new weather watch will be coordinated shortly
   for portions of lower Michigan, Indiana and Ohio.

   DISCUSSION...As of 0000 UTC regional RADAR imagery showed a
   well-developed convective line stretching from KGRB to KLOT.
   Numerous reports of wind damage and measured gusts of 50 to 60 mph
   have been reported with these storms over the last several hours.
   Ongoing within an extremely unstable airmass characterized by MLCAPE
   in excess of 4500 J/kg, observational trends and high-resolution
   model guidance suggest these storms will continue to pose a risk for
   damaging wind gusts this evening as they approach and eventually
   cross Lake Michigan. While some weakening is expected across the
   lake due to cooler temperatures, the strongly unstable environment
   and robust cold pool should allow storms to maintain their current
   organization.

   Downstream across lower Michigan, Northern Indiana and northwestern
   Ohio, a warm front was observed lifting north of Grand Rapids to
   near Detroit. South of this front, the airmass remains very unstable
   with MLCAPE of 2500-3500 J/kg. As the front continues to move north
   this evening, additional destabilization of the airmass is expected.
   As storms move back onshore around 0130 to 0200, the strongly
   unstable airmass will support a threat for damaging wind gusts. 

   A new weather watch will be coordinated shortly for portions of Lake
   Michigan, lower Michigan and northern Indiana.

   ..Lyons/Edwards.. 08/11/2021

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

   ATTN...WFO...DTX...APX...IWX...GRR...GRB...LOT...MKX...

   LAT...LON   43848775 44218755 44348708 44328629 44328564 44238495
               44038453 43788433 43288413 42528402 41998408 41578428
               41308481 41258572 41178658 41238734 41968767 43058781
               43848775