Storm Prediction Center Mesoscale Discussion 1158

   Mesoscale Discussion 1158
   NWS Storm Prediction Center Norman OK
   0525 PM CDT Tue Jun 16 2026

   Areas affected...northern into northeast MT and northwest ND

   Concerning...Severe potential...Watch unlikely 

   Valid 162225Z - 170030Z

   Probability of Watch Issuance...20 percent

   SUMMARY...The risk for isolated severe gusts and perhaps marginally
   severe hail will develop as storms intensify during the next few
   hours.

   DISCUSSION...Widely scattered thunderstorms are developing ahead of
   an amplifying upper trough over southern Alberta.  GOES and
   model-based upper flow fields show very strong westerly flow with
   80+ kt flow at 8 km AGL per the Glasgow, MT WSR-88D VAD.  Although
   low-level moisture is modest (surface dewpoints ranging from 45-50
   deg F), steepened 0-3 km lapse rates and cool mid levels are
   supporting upwards of 500-1000 J/kg SBCAPE.  Very long hodographs
   will support storm organization mainly in the form of a couple of
   supercells early during the convective life cycle before more storms
   and coalescing cold pools promotes more of a multicell mode.  The
   greater risk for severe hail will accompany the supercells before
   the risk for severe gusts also begins to increase owing to higher
   storm coverage.

   ..Smith/Gleason.. 06/16/2026

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

   ATTN...WFO...BIS...GGW...TFX...

   LAT...LON   48780942 48970824 48960393 48750161 48360088 47780094
               47310121 47200232 47450518 47960798 48260907 48490943
               48780942 

   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN