Mesoscale Discussion 1271
   NWS Storm Prediction Center Norman OK
   1245 PM CDT Fri Jun 13 2025

   Areas affected...Central into Eastern/Southeastern MT

   Concerning...Severe potential...Watch likely 

   Valid 131745Z - 131945Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Increasing thunderstorm coverage is expected across
   central and eastern/southeastern MT this afternoon. Large to very
   large hail and strong gusts are possible with these storms.

   DISCUSSION...Despite relatively modest temperatures, still in the
   mid/upper 60s, and low-level moisture, with dewpoints in the low to
   mid 50s, the airmass is quickly destabilizing across central and
   eastern MT. This destabilization is supported predominantly by
   cooling mid-level temperatures, which are already -11 to -15 deg C
   at 500 mb across the region. Southwesterly mid-level flow is
   expected to gradually strengthen throughout the day as a shortwave
   trough progresses across the Pacific Northwest into the region. The
   strengthening flow will contribute to orographic ascent across the
   higher terrain, with large-scale lift also increasing ahead of the
   approaching shortwave. Resulting combination of lift and
   destabilization is expected to foster widespread thunderstorms
   across the region. 

   Overall buoyancy is expected to remain relatively modest across
   central MT, while increasing slightly with southeasterly extent
   where better low-level moisture exists. Even so, there is enough
   buoyancy for strong updrafts, particularly when combined with the
   moderate to strong deep-layer vertical shear in place. Storms will
   likely persist off the terrain into more of the High Plains. The
   strong deep-layer shear will favor large to very large hail, with
   some hail greater than 2 inches in diameter possible. Strong and
   damaging outflow gusts that could reach or exceed 75 mph are also
   possible. Overall, the tornado risk is low, but greater low-level
   moisture and stronger southeasterly flow across eastern/southeastern
   MT suggests there is a relatively higher risk there than areas
   farther west.

   ..Mosier/Thompson.. 06/13/2025

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

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

   LAT...LON   46561316 47741128 48340707 47790545 46220535 45250752
               45321281 46561316 

   MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN