Mesoscale Discussion 1519
   NWS Storm Prediction Center Norman OK
   0515 PM CDT Mon Aug 17 2020

   Areas affected...southwestern South Dakota through western Nebraska
   and northeastern Colorado

   Concerning...Severe potential...Watch unlikely 

   Valid 172215Z - 180015Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Isolated storms may become capable of producing a few
   instances of hail and locally strong gusts through early evening
   from southwest SD through western NE into northeast CO. The overall
   magnitude of the threat and storm coverage are not expected to
   become sufficient for a WW.

   DISCUSSION...Early this evening isolated storms are in the process
   of developing from southwestern SD into western NE within a modest
   northwesterly flow regime. Up to 500-1000 J/kg MLCAPE is supported
   where narrow corridor of low to mid 50s dewpoints reside beneath
   eastern fringe of 7 C/km mid-level lapse rates. Forcing is weak and
   storm development is primarily driven by diurnal heating and subtle
   boundaries. Nevertheless, 30-40 kt effective bulk shear and marginal
   instability may be sufficient to support some marginal supercell
   structures next 2-3 hours with a few instances of hail and locally
   strong wind gusts possible. Activity should begin to diminish near
   sunset as the surface layer stabilizes.

   ..Dial/Edwards.. 08/17/2020

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

   ATTN...WFO...LBF...UNR...BOU...CYS...

   LAT...LON   40340331 41060377 42400390 43200375 43490307 42760245
               41950220 41290214 40500252 40340331