Mesoscale Discussion 1250
   NWS Storm Prediction Center Norman OK
   0341 PM CDT Fri Jul 17 2020

   Areas affected...central Montana

   Concerning...Severe potential...Watch unlikely 

   Valid 172041Z - 172245Z

   Probability of Watch Issuance...5 percent

   SUMMARY...Isolated thunderstorms developing late this afternoon and
   evening may pose an isolated hail threat. A watch is not anticipated
   due to the isolated nature of the threat.

   DISCUSSION...Recent satellite imagery across central Montana shows
   an increase in stratus and cumuli-form cloud cover associated with
   the approach of an upper-level trough to the west. Additionally,
   regional radar imagery has shown hints at elevated convective
   development with brief 40+ dBz echoes. A few lightning strikes have
   also been noted. However, these features have been transient in
   nature and suggest that robust convective initiation will likely
   hold off for another one to three hours. MUCAPE has gradually
   increased to 250-500 J/kg, and pockets up to 1000 J/kg may emerge by
   late afternoon. Despite the meager instability, deep layer shear
   remains strong with 40-50 knots of effective bulk shear. This shear
   may compensate for the instability and help organize one or two
   elevated storms during the late afternoon and evening hours if
   robust convection can become established. The main hazards would be
   severe hail, but given a deep, dry boundary-layer over the region,
   strong downburst winds can not be ruled out. Since this threat
   should be limited spatially and is conditional on the development of
   sustained convection, a watch is not likely.

   ..Moore/Hart.. 07/17/2020

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

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

   LAT...LON   46171318 46801169 47131018 47400856 47430757 47050707
               46590691 45980822 45620954 45321110 45331232 45631310
               46171318