ZCZC SPCSWOMCD ALL
ACUS11 KWNS 010051 
SPC MCD 010051 
CAZ000-010445-

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 

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