Mesoscale Discussion 1612
   NWS Storm Prediction Center Norman OK
   0306 PM CDT Thu Aug 26 2021

   Areas affected...central Montana

   Concerning...Severe potential...Watch possible 

   Valid 262006Z - 262200Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Isolated strong/severe storms including a few supercells
   may develop late this afternoons across central Montana. Damaging
   winds and hail will be the primary severe risk.

   DISCUSSION...Ahead of a mid-level shortwave trough evident from
   afternoon WV imagery, deepening cumulus towers were noted along the
   eastern edge of the Rockies across central Montana. Here, diurnal
   heating and weak upslope flow are supporting gradual destabilization
   with 500-1000 J/kg of MLCAPE present according to SPC mesoanalysis.
   Mid-level flow associated with the trough is also supporting between
   25 and 35 kt of effective shear favorable for organized clusters and
   perhaps a few supercell structures. Relatively dry low levels
   suggest downdraft and cold pool development will favor a damaging
   wind threat with the stronger storms. Cool temperatures aloft
   beneath the mid-level trough may also support the potential for
   severe hail, especially with any rotating storms.

   Storm development and an increase in severe risk appears possible by
   22-23z as initial updrafts begin to move off of the the higher
   terrain into central Montana. Considerable uncertainty remains on
   the magnitude of severe threat as hi-res guidance suggests storm
   coverage may be quite limited. Despite the uncertainty, the
   CAPE/Shear space would support at least an isolated severe wind/hail
   risk with any storms that develop. Convective trends will be
   monitored for a possible weather watch.

   ..Lyons/Dial.. 08/26/2021

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

   ATTN...WFO...BYZ...GGW...TFX...

   LAT...LON   47890892 48070757 47460677 46640623 46060627 45160698
               45220817 46410931 47080982 47890892