Mesoscale Discussion 0860
   NWS Storm Prediction Center Norman OK
   0625 PM CDT Sat Jun 06 2020

   Areas affected...Eastern WY...NE Panhandle...Western SD

   Concerning...Severe Thunderstorm Watch 263...264...

   Valid 062325Z - 070100Z

   The severe weather threat for Severe Thunderstorm Watch 263, 264
   continues.

   SUMMARY...Fast-moving squall line will surge across the remainder of
   ww263 into ww264. Severe wind gusts are the primary risks, though an
   isolated tornado can not be ruled out along the eastern periphery of
   the Black Hills.

   DISCUSSION...Long-lived linear MCS has progressed across southern
   WY/CO and is now surging east of the mountains across the High
   Plains. Latest radar data suggests leading bow is racing northeast
   in excess of 50kt and surface winds greater than 50kt remain likely,
   with some approaching 70kt possible. Numerous measured severe wind
   gusts have been common with this squall line.

   Air mass downstream across western SD is considerably more
   moist/buoyant. Forecast soundings favor supercells but current
   linear storm mode will likely be maintained given the longevity of
   the MCS supported by strong large-scale forcing. While a tornado can
   not be ruled out east of the Black Hills, current thinking is severe
   wind gusts will be the primary threat.

   ..Darrow.. 06/06/2020

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

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

   LAT...LON   41050335 42710413 44280469 44590258 42360166 41050335