Mesoscale Discussion 0634
   NWS Storm Prediction Center Norman OK
   0623 PM CDT Mon May 18 2020

   Areas affected...western Montana

   Concerning...Severe potential...Watch unlikely 

   Valid 182323Z - 190130Z

   Probability of Watch Issuance...20 percent

   SUMMARY...A supercell or two capable of producing large hail and
   downburst winds will be possible this evening across western
   Montana. Due to expected sparse storm coverage, a WW is not
   anticipated.

   DISCUSSION...Orographic forcing and a northeast-advancing vorticity
   maximum embedded within a diffluent upper flow regime will promote
   the development of a few thunderstorms across western MT this
   evening. Instability is weak, on the order of 300-600 J/kg MUCAPE,
   but 40-45 kt effective bulk shear will support the potential for a
   couple of supercells developing initially over the higher terrain of
   western MT and subsequently spreading northeast. Isolated large hail
   and downburst winds will be possible, but limited instability and
   expected sparse coverage of any severe events should preclude a WW
   issuance.

   ..Dial/Hart.. 05/18/2020

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

   ATTN...WFO...TFX...MSO...

   LAT...LON   48141044 46871142 46111334 46791394 47991289 48561133
               48141044