Storm Prediction Center Mesoscale Discussion 2158

   Mesoscale Discussion 2158
   NWS Storm Prediction Center Norman OK
   0703 PM CDT Thu Aug 27 2026

   Areas affected...central Montana

   Concerning...Severe Thunderstorm Watch 634...

   Valid 280003Z - 280100Z

   The severe weather threat for Severe Thunderstorm Watch 634
   continues.

   SUMMARY...High-based shower and thunderstorm activity will remain
   capable of strong to severe gusts this evening.

   DISCUSSION...Across WW634, widely scattered showers and
   thunderstorms were ongoing this evening over much of central MT. The
   more robust of these clusters (near the Great Falls vicinity) have
   produced occasional measured severe gusts over the last 90 min. The
   overall environment remains very supportive of strong downdrafts
   across much of central MT owing to steep low-level lapse rates (8-9
   C/km) and high cloud bases above 3 km. While instability remains
   modest (500-1000 J/kg of MLCAPE) surface temperatures in the upper
   80s and low 90s should be sufficient to maintain the ongoing storms
   as they move east/northeast this evening. Severe gust potential
   appears maximized near the aforementioned established clusters of
   storms, but any coherent downdraft will likely be capable of strong
   to severe gusts this evening.

   ..Lyons.. 08/28/2026

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

   ATTN...WFO...BYZ...GGW...RIW...TFX...PIH...MSO...

   LAT...LON   47200842 45990743 45640755 45220816 45060874 44731037
               44751222 45221288 48941221 48970929 47200842 

   MOST PROBABLE PEAK WIND GUST...65-80 MPH