Mesoscale Discussion 1171
   NWS Storm Prediction Center Norman OK
   0126 PM CDT Fri Jul 10 2020

   Areas affected...far eastern Montana...western North
   Dakota...western/central South Dakota...and far northeastern Wyoming

   Concerning...Severe potential...Watch likely 

   Valid 101826Z - 102030Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Severe storms are expected to develop along an approaching
   cold front/dryline and migrate southeastward across western portions
   of the discussion area initially.  One or two WW issuances are
   expected.

   DISCUSSION...The airmass along and ahead of a quickly moving cold
   front in eastern Montana and ahead of a dryline in northeastern
   Wyoming continues to destabilize due to ample insolation/surface
   warming.  Objective analyses indicate 1000-2500 J/kg MUCAPE across
   the discussion - higher with southern extent.  Convergence along the
   aforementioned boundaries and an approaching mid-level shortwave
   trough over central Montana is expected to foster an increase in
   convective coverage and intensity perhaps as early as 19Z, but
   especially in the 21-23Z timeframe.  This notion is also supported
   by several recent CAMs.

   Over time, storms should organize and grow upscale into linear
   segments and clusters, with strong deep shear supporting
   organization.  Relatively weak low-level shear should limit any
   tornado threat, though any favorable interaction with a remnant
   outflow boundary across southwestern South Dakota and vicinity may
   foster a brief tornado threat.  Steep mid-level lapse rates and the
   surface-based nature of the storms will support large hail and
   severe wind gusts with convection, and any isolated, supercellular
   convection may pose a significant hail risk.  Any bowing segments
   that can materialize may also pose a threat for significant severe
   wind gusts as well.

   The overall scenario suggests high probability of a WW issuance in
   the area this afternoon - perhaps before 20Z.

   ..Cook/Kerr.. 07/10/2020

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

   ATTN...WFO...FSD...ABR...BIS...LBF...UNR...BYZ...GGW...

   LAT...LON   46250514 46760497 47730466 48300438 48610341 48530243
               47760158 46480097 44879990 43929883 43149874 42699995
               42820185 43220333 43710451 45300514 46250514