Storm Prediction Center Mesoscale Discussion 1749

   Mesoscale Discussion 1749
   NWS Storm Prediction Center Norman OK
   0303 PM CDT Tue Jul 30 2024

   Areas affected...North and South Dakota

   Concerning...Severe potential...Watch possible 

   Valid 302003Z - 302200Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Thunderstorm development is anticipated in the next 1-2
   hours across the western Dakotas. Storms are expected to intensify
   as they migrate east into central North and South Dakota. Watch
   issuance is possible later this afternoon/evening as the severe
   threat becomes more prominent.

   DISCUSSION...Recent GOES visible imagery shows a gradual increase in
   cumulus along a surface trough and within the Black Hills in western
   SD. Mid to upper-level cirrus overspreading the region from the west
   is indicative of gradually increasing synoptic-scale ascent ahead of
   a mid-level shortwave trough over ID/MT. Thunderstorm development
   appears likely in the coming hours as ascent continues to increase
   and continued daytime heating erodes any lingering MLCIN. 

   Initial thunderstorms across the western Dakotas will develop within
   a relatively dry/well-mixed environment with LCL heights between 3.0
   to 3.5 km. This environment will favor strong downdraft
   accelerations and rapid cold pool development/expansion with an
   attendant severe wind risk. Convection is expected to intensify as
   it moves east through the evening hours and encounters a reservoir
   of richer low-level moisture (well-sampled by a recent 19 UTC ABR
   sounding). Adequate deep-layer wind shear (around 30-35 knots)
   should support organized convection. Storm coverage remains somewhat
   uncertain given weak forcing for ascent. While the environment may
   support a supercell or two this evening, clustering of initial cells
   is possible and may promote upscale growth and a more robust wind
   threat. Trends will be monitored and watch issuance may be needed
   later this afternoon or evening to address this concern.

   ..Moore/Gleason.. 07/30/2024

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

   ATTN...WFO...ABR...BIS...UNR...

   LAT...LON   44930049 44030188 43840218 43790254 43850287 44170313
               44510327 44810330 46100323 46540311 46740298 47060283
               47900222 48380147 48400078 48060016 47429973 46649967
               46039979 45490003 44930049