Mesoscale Discussion 0927
   NWS Storm Prediction Center Norman OK
   0526 PM CDT Wed Jun 17 2020

   Areas affected...Portions of central and eastern South
   Dakota...north-central Nebraska

   Concerning...Severe potential...Watch possible 

   Valid 172226Z - 180030Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Storms are in the process of developing both along the
   cold front and along a pre-frontal confluence band from
   north-central Nebraska into eastern South Dakota. Damaging wind
   gusts will be the primary threat overall. Isolated large hail will
   also be possible, particularly with earlier, more discrete activity.
   A WW will be possible in the next 1-2 hours.

   DISCUSSION...Agitated cumulus have developed along the front in
   north-central Nebraska. Given the character of these cumulus on
   visible satellite, it may be a couple of hours before storms
   initiate. Farther north into central South Dakota, capping appears a
   bit stronger and storm development may be further delayed. Shear
   along and just east of the cold front is roughly parallel to the
   boundary and only a modest 25-35 kts. Still, moderate buoyancy to
   the east and steep low- and mid-level lapse rates suggests a risk
   for large hail (despite fairly warm 500 mb temps) and damaging wind
   gusts will exist. Supercell structures that develop may be
   short-lived given the boundary parallel shear. The temporal window
   for large hail will depend on how long storms can remain discrete.

   West of Aberdeen, SD, a few more substantial towering cumulus have
   developed over the last hour or so. This activity is developing in
   moderate buoyancy (around 2500 J/kg MLCAPE). Deep-layer shear in the
   open warm sector is weaker than in the vicinity of the cold front to
   the west. Given the buoyancy and steep mid-level lapse rates, large
   hail and damaging winds will be possible with this activity. Later
   in the evening, further storm development along the cold front may
   occur and move into this area.

   A WW is possible in the next 1-2 hours.

   ..Wendt/Thompson.. 06/17/2020

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

   ATTN...WFO...FGF...FSD...ABR...BIS...LBF...UNR...

   LAT...LON   42690208 43420128 45150036 45909964 45919915 45989853
               45949801 45799739 45629734 44799768 44329822 42429986
               41810080 41530174 42010215 42690208