Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 220949
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
249 AM PDT Fri Mar 22 2024

.SYNOPSIS...

Winter returns later today with gusty winds and periods of rain
and mountain snow through Sunday. Plan on Sierra travel impacts
this weekend. Unsettled weather remains favored through next week
as a train of additional storms swings through our region.

&&

.DISCUSSION...

Time to break the sweaters (and shovels, for our Sierra communities)
back out as winter decides to make a reappearance this weekend. An
upper-level closed low currently located off the NorCal coast moves
inland today, with an attendant cold front sweeping through the
region this afternoon and evening. Southwesterly winds begin to ramp
up this morning ahead of the front, peaking this afternoon around 30-
40 mph for valleys and 80-90 mph along Sierra ridges. Winds will
dampen this evening as a precipitation band accompanying the cold
front passage moves into the region. Light showers begin first in
northeast CA and the Sierra from US-50 northward around 2-3 PM,
before the main precip band moves in to those aforementioned areas
around 7-8 PM. The band will continue to spread southward along the
Sierra through the night, with light spillover into western NV
overnight into the early morning hours on Saturday. Expect showers
to decrease in intensity by daybreak on Saturday. Expect winds to
increase again during this lull in precip with gusts to 25-35 mph
in valleys and 60-70 mph along Sierra ridges.

The closed low looks to split on Saturday, with one shortwave
ejecting off into the Northern Plains and the other continuing to
dig southward roughly along the CA coast. This will lead to a
re-invigoration of precip around the late afternoon hours
Saturday, with showers continuing into Sunday morning. Decent
instability sets up over the region during the afternoon hours on
Saturday and Sunday. This introduces a low-end chance (10-15%) for
isolated afternoon thunderstorms or pellet showers, mainly in the
Sierra.

Snow levels begin around 7000 feet at the onset of precipitation
this afternoon, hovering between 5500-6500 feet during peak
intensity, then crashing well below valley floors behind the main
precip band. Some snowflakes may reach valley floors near the tail
end of this first round early Saturday morning, but no accumulation
is expected. Snow levels rise to around 4500-5000 feet during the
second round of precip Saturday afternoon into Sunday morning.
All in all, snowfall totals through midday Saturday bring 8-14"
to the Sierra crest mainly from Alpine County northward, and 6-12"
southward along the crest in Mono County. Limited spillover from
this system will lead to a tight gradient in snowfall totals east
of the Sierra crest, with 2-6" for lower elevation communities
including Truckee, South Lake, and Mammoth Lakes. However, there
is a 20% chance of 8" snowfall for Mammoth Lakes and western Tahoe
Basin communities, along with spotty Sierra and northeast CA
locations receiving an additional 3-10" of snowfall from the more
convective snow shower bands from late Saturday into Sunday AM.

We will see much cooler temperatures settling in this weekend,
dropping to around 10 degrees below average behind the cold front
on Saturday. This trend sticks around through the entirety of
next week, as a train of several storm systems keep the overall
pattern active into the end of March. The next notable storm in
the queue looks to arrive on Wednesday, bringing additional
periods of valley rain, mountain snow, and gusty winds. Whitlam

&&

.AVIATION...

VFR conditions prevail this morning ahead of an incoming storm
system.

FL100 winds increase after 12z today, remaining elevated through
this afternoon and Saturday, peaking around 50 kts. Surface winds
will be from the southwest with gusts 25-35 kts for all regional
terminals.

Precipitation moves into the Sierra and NE CA after 0z Saturday,
with peak snow rates at KTRK/KTVL between 3-12z Saturday, leading to
a period of IFR/LIFR conditions. Spillover into western NV occurs
roughly during that same time frame, with light rain showers
leading to lowering CIGS and subsequent periods of MVFR conditions
for KRNO/KCXP/KMEV. KMMH will see snow showers between 6-12z with
periods of MVFR/IFR conditions possible. Whitlam

&&

.AVALANCHE...

For the storm this evening through Saturday AM...

* Liquid totals (SWE): Generally from 0.9-1.4" for the Sierra
  crest west of Tahoe southward to Alpine County, and 0.6-1.1" for
  Mono County.

* Peak Snowfall Rates: Up to 2"/hour for a 3-6 hour period within
  the 8 PM Fri-5 AM Sat time frame.

* Snow-Liquid Ratios: Starting wetter at 8-10:1, then trending
  somewhat drier at 10-13:1 toward end of event.

* Peak Ridge Level Wind Gusts: 80-90 mph.

-MJD

&&

.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory from 2 PM this afternoon to 11 AM PDT
     Saturday NVZ002.

     Lake Wind Advisory from 2 PM this afternoon to 11 PM PDT this
     evening NVZ004.

CA...Winter Weather Advisory from 2 PM this afternoon to 11 AM PDT
     Saturday CAZ071-072.

     Winter Weather Advisory from 5 PM this afternoon to 11 AM PDT
     Saturday CAZ073.

&&

$$


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