Mesoscale Discussion 0182
   NWS Storm Prediction Center Norman OK
   0353 PM CDT Sat Mar 14 2020

   Areas affected...the Sierra Nevada

   Concerning...Heavy snow 

   Valid 142053Z - 150300Z

   SUMMARY...Heavy snow is developing across northern Sierra Nevada
   with snow spreading farther south along the range through the
   afternoon. Heavy snow is likely down to 4000 to 5000 feet into
   tomorrow with rates of 2-4+ inches per hour.

   DISCUSSION...A deepening upper-level trough is slowly sliding
   southward over the West Coast. Heights and temperatures have fallen
   aloft across northern/central California with a couple of weaker
   disturbances having rotated over northern California/Nevada today
   per water vapor imagery. Low/mid-level flow is becoming more
   southwesterly/perpendicular to the Sierra, which will increase
   topographic lift and precipitation rates. Moisture advection from
   the eastern Pacific will continue with the richer moisture plume
   slowly shifting south along/ahead of the movement of the upper-level
   trough.

   Shallow instability is aiding precipitation rates and this will
   continue as mid-level temperatures fall this afternoon/evening.
   Heavy snow will likely continue above 4000-5000 feet into tomorrow
   with occasional convective enhancements to the topographic lifting
   as vorticity maxima rotate around the base of the trough. Spillover
   precipitation is possible in the lee of the Sierra and will occur
   intermittently as diabatic heating and latent heat release increase
   from convection to help transport moisture over the crest. Snowfall
   rates of 2-4+ inches per hour are expected into tomorrow with the
   windward (western slopes) and areas near the crest favored for the
   highest rates.

   ..Nauslar.. 03/14/2020

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

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

   LAT...LON   39082106 39892169 40152141 40052089 39421991 38911984
               36761843 36571877 37581980 38332049 39082106