Mesoscale Discussion 1473
   NWS Storm Prediction Center Norman OK
   0616 PM CDT Wed Aug 12 2020

   Areas affected...eastern Montana/western North Dakota

   Concerning...Severe potential...Watch possible 

   Valid 122316Z - 130115Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Isolated storm development is expected to continue over
   the eastern Montana vicinity, though more widespread convection
   should remain north of the international border.  Locally damaging
   winds will accompany any stronger storm, though need for a WW
   remains questionable due to the rather isolated nature of the risk
   that is expected this evening.

   DISCUSSION...Latest visible satellite and radar loops show storms
   developing convection across east-central and northeast Montana at
   this time, with more widespread convection north of the U.S./Canada
   border into southern Saskatchewan.  The storms are initiating in
   response to increasing ascent/uvv -- per WV imagery -- as a
   short-wave trough centered over western Montana continues shifting
   east-northeastward.

   Greater instability is indicated over southern Saskatchewan --
   coincident with more robust/widespread storm development.  Farther
   south, some capping issues are noted in model data -- particularly
   eastward into North Dakota -- likely limiting storm coverage at this
   time.  Additionally, shear remains rather modest across the area,
   with only around 20 kt westerly flow at mid levels.  While flow
   aloft -- both low-level and deep-layer -- will increase somewhat
   this evening, capping will also reassert itself as the boundary
   layer cools.  These factors continue to cast uncertainty with
   respect to degree of severe risk, and any corresponding need for
   potential WW issuance.  While locally damaging winds can be expected
   with any stronger storm, given the deep/dry mixed layer, we will
   continue to evaluate the environmental evolution and related trends
   in convective development, to further assess the need for watch
   issuance.

   ..Goss/Guyer.. 08/12/2020

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

   ATTN...WFO...BIS...BYZ...GGW...

   LAT...LON   48790485 49000407 48970039 47060085 46600216 46560420
               47130475 48790485