Mesoscale Discussion 1540
   NWS Storm Prediction Center Norman OK
   0526 PM CDT Fri Aug 21 2020

   Areas affected...The Upper Peninsula of Michigan and northeast
   Wisconsin

   Concerning...Severe potential...Watch unlikely 

   Valid 212226Z - 220000Z

   Probability of Watch Issuance...5 percent

   SUMMARY...Ongoing and developing convection across the southern U.P.
   of Michigan and northeast Wisconsin will continue to pose a
   transient hail and wind threat through sunset. The spatial extent
   and duration of the threat should remain too low to warrant a watch.

   DISCUSSION...Thunderstorms ongoing along the border of WI and the
   U.P. of MI continue to remain somewhat organized due to a zone of
   enhanced mid-level flow in the vicinity of a shortwave trough moving
   across southern Ontario. This enhanced flow overlaps a favorably
   unstable environment across northeast WI and the southern U.P.
   characterized by 1500-2000 J/kg MLCAPE. This zone of favorable
   CAPE/shear parameter space is relatively limited spatially, but new
   convection across Iron County, MI is developing within this window.
   This suggests that at least a transient threat for severe hail and
   wind could continue for the next one to two hours as ongoing
   convection continues to move towards Lake Michigan and new storms
   develop to the northwest. 

   However, given the spatially limited nature of the threat, only
   marginally supportive deep-layer shear (around 30 knots), and some
   degree of convective overturning ahead of the developing storms (due
   to prior convection), the overall severe risk appears limited in
   duration and coverage. As such, a watch is not expected.

   ..Moore/Edwards.. 08/21/2020

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

   ATTN...WFO...MQT...GRB...

   LAT...LON   46668920 46648835 46168728 45728693 45248699 44858731
               44978797 45478862 45918903 46258938 46668920