Storm Prediction Center Mesoscale Discussion 1501

   Mesoscale Discussion 1501
   NWS Storm Prediction Center Norman OK
   0714 PM CDT Sun Jun 30 2024

   Areas affected...southern and eastern MT

   Concerning...Severe Thunderstorm Watch 492...

   Valid 010014Z - 010145Z

   The severe weather threat for Severe Thunderstorm Watch 492
   continues.

   SUMMARY...Ongoing marginal/isolated severe threat should increase in
   intensity and perhaps coverage as cells shift northeastward into
   eastern Montana this evening. An additional severe thunderstorms
   watch may be needed to the east of WW 492.

   DISCUSSION...A single, but longer-lived discrete cell has steadily
   progressed northeastward across southwest to south-central MT, now
   northwest of Billings. This storm has seemingly struggled within the
   weak buoyancy and moderate MLCIN environment, despite ample
   southwesterly speed shear above 3-km AGL per Billings VWP data.
   Downstream over the western Dakotas into eastern MT, a southeasterly
   low-level jet is consistently progged to strengthen substantially
   over the next few hours. This will result in increasing forcing for
   ascent coupled with low-level moistening that should yield greater
   MLCAPE/diminishing MLCIN. It remains plausible that the convection
   northwest of Billings should intensify as this occurs. But given
   recent observational trends, confidence has lowered on the degree of
   convective coverage as depicted by afternoon guidance. Still, an
   increase in severe may occur at some point this evening and a
   downstream watch is being considered.

   ..Grams/Smith.. 07/01/2024

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

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

   LAT...LON   45041306 45751096 46410966 47090878 48080773 48580676
               48430556 47560500 46890497 46130774 44601283 45041306