Mesoscale Discussion 0956
   NWS Storm Prediction Center Norman OK
   0244 PM CDT Sun Jun 21 2020

   Areas affected...southern/central Minnesota...northern Iowa...far
   southeast South Dakota

   Concerning...Severe potential...Watch possible 

   Valid 211944Z - 212145Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Strong to severe storms are expected this afternoon and
   evening across portions of southern Minnesota and into northern Iowa
   and far southeast South Dakota. Damaging winds and large hail are
   the main severe threats as storms move east-southeast. A watch
   issuance is possible.

   DISCUSSION...Storms have started to develop along enhanced surface
   convergence in southern Minnesota. Surface temperatures have warmed
   into the low 80s F across the area with dewpoints in the low to mid
   60s F. MLCAPE is now 1000-2000 J/kg as steep mid-level lapse rates
   have nosed into the area from the southwest and along with the
   aforementioned warm/moist boundary layer. Discrete cells including
   possible transient supercell structures are possible initially, but
   it is likely storms will begin to line out along the stronger
   surface convergence. As storms develop they will move east-southeast
   with upscale growth into a QLCS possible if not likely, especially
   as an upstream mid-level shortwave trough approaches.

   Large hail and damaging winds gusts are possible with these storms.
   While surface flow is relatively veered, a brief tornado cannot be
   ruled out, especially with initial convection near the surface
   boundary. The severe wind threat would increase if the storms can
   congeal into a QLCS. There is potential for cold pool development
   given the orientation of the surface boundary to the upper-level
   flow and ongoing cloud cover just north of the developing
   thunderstorms.

   ..Nauslar/Guyer.. 06/21/2020

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

   ATTN...WFO...ARX...MPX...DMX...FSD...

   LAT...LON   42819524 42989643 43049729 43509762 44329686 44599578
               44789471 44989383 45069342 45049285 44079258 43079292
               42809367 42819524