Mesoscale Discussion 1523
   NWS Storm Prediction Center Norman OK
   0159 PM CDT Tue Aug 18 2020

   Areas affected...San Bernardino and San Jacinto Mountains Vicinity

   Concerning...Severe potential...Watch unlikely 

   Valid 181859Z - 182100Z

   Probability of Watch Issuance...5 percent

   SUMMARY...Scattered storms are expected to develop along the higher
   terrain this afternoon. A few strong/severe outflow gusts are
   possible. No WW is expected this afternoon.

   DISCUSSION...Thunderstorms have recently initiated within the San
   Bernardino Mountains with cumulus continuing to build along the San
   Jacinto Mountains. Within the next hour or two, greater storm
   coverage is expected. Flow at 500 mb is a modest 30 kts leading to
   25-30 kts of shear across southern California. The is some question
   how far storms will move off the terrain with weak cloud-bearing
   winds. Even so, a deeply-mixed boundary layer with 100-110 F
   temperatures this afternoon will support strong to severe outflow
   winds propagating away from thunderstorm cores. The areal extent of
   the threat will remain quite limited and no WW is anticipated for
   this activity.

   ..Wendt/Grams.. 08/18/2020

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

   ATTN...WFO...PSR...VEF...SGX...HNX...LOX...

   LAT...LON   34731809 35031770 35041711 34871655 34211640 33741655
               33571675 33651741 34381813 34731809