Mesoscale Discussion 1551
   NWS Storm Prediction Center Norman OK
   0512 PM CDT Sat Jul 20 2019

   Areas affected...Northern Indiana...southern Michigan...and
   northwest Ohio

   Concerning...Severe potential...Watch possible 

   Valid 202212Z - 202345Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Strong to occasionally severe storms are expected through
   the evening. A severe thunderstorm watch is possible.

   DISCUSSION...An outflow dominant line of storms is moving south out
   of Michigan and has produced occasional 40 to 50 mph wind gusts.
   Additional development has started in far southwest Michigan as this
   boundary interacts with a very unstable air mass (MLCAPE ~3000
   J/kg). In addition, a storm cluster currently near Chicago may move
   into this area later this evening. Shear is quite weak (20 to 25 kts
   per KIWX VWP), and is oriented mostly parallel to the boundary.
   However, given the instability, some strong to occasionally severe
   storms cannot be ruled out. A severe thunderstorm watch may be
   needed if stronger cores develop this evening.

   ..Bentley/Thompson.. 07/20/2019

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

   ATTN...WFO...CLE...DTX...IWX...GRR...LOT...

   LAT...LON   41808748 42128677 42188551 42108463 42088386 41928362
               41718354 41488365 41278413 41178467 41178546 41258615
               41288670 41528745 41808748