Mesoscale Discussion 1547
   NWS Storm Prediction Center Norman OK
   0445 PM CDT Sat Aug 22 2020

   Areas affected...Southeast Nevada and northwest Arizona

   Concerning...Severe potential...Watch unlikely 

   Valid 222145Z - 222315Z

   Probability of Watch Issuance...5 percent

   SUMMARY...Isolated thunderstorms will continue to pose a transient
   hail risk, but the threat will be too limited in duration and
   coverage to warrant a watch.

   DISCUSSION...Isolated thunderstorms ongoing across southeast NV and
   northwest AZ have shown evidence of periodically supporting severe
   hail over the past hour (per recent MRMS MESH estimates and a
   three-body-scatter-spike noted in one cell south of the Las Vegas,
   NV area). The environment across this region features 1500-2000 J/kg
   MLCAPE, but little deep layer shear based on the KESX VAD. However,
   RAP forecast soundings show 20-25 knots of bulk wind shear within
   the cloud bearing layer that may be supporting a brief hail threat
   with the stronger updraft pulses. A transient hail threat should
   continue for the next one to two hours as additional isolated storms
   develop along the higher terrain across the region and off of
   convective outflows. Steep low-level lapse rates (8-9 C/km per
   recent RAP analyses) associated with deep, dry boundary layers will
   also support a downburst wind potential. Due to the transient and
   isolated nature of the threat, a watch is not expected.

   ..Moore/Grams.. 08/22/2020

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

   ATTN...WFO...FGZ...SLC...VEF...

   LAT...LON   37111493 36521578 35751596 35291567 34941513 34721443
               34701366 34841279 35181241 35721231 36261247 36801288
               37151408 37111493