Mesoscale Discussion 0180
   NWS Storm Prediction Center Norman OK
   0651 PM CST Thu Feb 29 2024

   Areas affected...Portions of the Sierra in northern California

   Concerning...Heavy snow 

   Valid 010051Z - 010445Z

   SUMMARY...Snowfall rates are expected to increase to near 2-3 inches
   per hour with localized blizzard conditions across portions of the
   Sierra in northern California in the 01-06Z time frame.

   DISCUSSION...Within the base of a deep midlevel cyclone centered off
   the British Columbia coast, the exit region of a robust
   mid/upper-level jet streak will impinge on the northern Sierra
   during the next few hours, while a related cold front moves
   southeastward across the region. The associated increase in
   large-scale ascent/frontal forcing, augmented by strengthening
   upslope flow, will continue to favor an increase in precipitation
   rates into tonight. This increasing ascent is already becoming
   evident in low/mid-level water-vapor loops and regional radar data.
   Given the overlap of strengthening ascent and influx of Pacific
   moisture (including a relatively deep and saturated dendritic growth
   zone), snowfall rates are expected to increase to near 2-3 inches
   per hour over portions of the northern Sierra (with locally higher
   rates possible). Current thinking is that these heavier rates will
   become more persistent in the 01-06Z time frame as the cold front
   continues southeastward (supported by the latest high-resolution
   guidance), with heavy snow persisting into the overnight hours. The
   highest rates will likely occur at elevations above 5000-6000 feet. 

   In addition, strengthening low-level flow accompanying the
   mid/upper-level speed maximum and cold front will likely support
   localized blizzard/whiteout conditions, given the potential for 50+
   mph gusts and the heavy snowfall rates.

   ..Weinman.. 03/01/2024

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

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

   LAT...LON   38221950 38021972 38242005 38922046 39492080 39712112
               39912108 40022080 39652042 38681989 38221950