Storm Prediction Center Mesoscale Discussion 165

   Mesoscale Discussion 0165
   NWS Storm Prediction Center Norman OK
   0903 PM CDT Wed Mar 12 2025

   Areas affected...portions of the Sierra over central California

   Concerning...Heavy snow 

   Valid 130203Z - 130600Z

   SUMMARY...Heavy snow should continue over the next several hours,
   with snowfall rates potentially increasing to over 2 inches per hour
   soon.

   DISCUSSION...Deep-layer moisture and ascent persists across portions
   of California into the Great Basin with the approach of a potent
   upper trough. Deep-layer cold-air advection with the upper trough's
   approach is encouraging the column to cool to the freezing mark over
   higher elevations of the sierra. Here, surface temperatures are
   already dipping into the mid 30s F, where the KTRK ASOS recently
   reported heavy snow. The current thinking is that snowfall rates
   should only continue to increase with increasing lift within a
   moistening, cooling column. Synoptic-driven ascent, combined with
   mesoscale orographic lift, will support heavy snowfall rates over
   the higher elevations of the Sierra, with over 2 inch/hour snowfall
   rates possible in a few locations.

   ..Squitieri.. 03/13/2025

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

   ATTN...WFO...REV...HNX...STO...

   LAT...LON   37491907 37661942 38071995 38842058 39802121 39962096
               39872054 39392020 38071916 37661886 37541889 37491907