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Mesoscale Discussion 1325
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   Mesoscale Discussion 1325
   NWS Storm Prediction Center Norman OK
   0340 PM CDT Wed Jul 21 2021

   Areas affected...Western Montana and Northeast Idaho

   Concerning...Severe potential...Watch unlikely 

   Valid 212040Z - 212215Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Convective initiation occurring amid an environment
   conducing to support a damaging wind and severe hail threat. Watch
   issuance unlikely at this time.

   DISCUSSION...Regional satellite shows a broad area of cumulus
   development over portions of western Montana, likely in association
   with ascent from a mid-level short-wave trough entering the region,
   as evidenced in water vapor imagery. Additionally, strong heating in
   the wake of mid- and high-level clouds/smoke has allowed surface
   temperatures to warm into the mid 80s F, producing strong low-level
   lapse rates amid rich low-level moisture, characterized by dew point
   temperatures in the mid 50s F. These conditions, along with moderate
   mid-level lapse rates and cool mid-level temperatures (evident in an
   18z sounding from southwest MT) have led to sufficient
   destabilization for convective initiation, with MLCAPE near 1000
   J/kg. The aforementioned short-wave is embedded within marginally
   enhanced southwesterly mid-level flow, sufficient to produce 35-40
   kt of effective bulk shear.

   Current expectation is for storms to become more numerous in the
   next 1-2 hours. Given the aforementioned thermodynamic and kinematic
   conditions, storms may become organized enough to produce damaging
   winds and severe hail in the strongest cells. At this time, it does
   not appear that storm coverage will be expansive enough to warrant
   watch issuance. However, convective trends will continue to be

   ..Karstens/Hart.. 07/21/2021

   ...Please see for graphic product...


   LAT...LON   45431533 47411516 48941341 48411194 45591165 45431533 

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