Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 281014
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
314 AM PDT Thu Mar 28 2024

.SYNOPSIS...

Moderate-to-heavy mountain snow and valley rain accompanying a cold
front passage will taper off areawide around sunrise. Gusty westerly
winds continue through this afternoon, though lighter in comparison
to yesterday. We will see a brief break between storms through
Friday morning, with the next storm in the queue bringing periods of
valley rain and mountain snow through the holiday weekend. Drier and
milder conditions return early-mid next week.

&&

.DISCUSSION...

Current surface obs and radar imagery indicate the cold front is
making its passage across the Sierra early this morning. A band of
moderate-to-heavy mountain snow and valley rain is evident along the
frontal boundary, with more showery conditions ahead of it. Peak
snowfall rates in the Sierra (generally between 1-2"/hr) are
expected from current time of writing through around 4 AM for the
Tahoe Basin, and between 2 AM to 7 AM for the high Sierra in Mono
County as the front continues to trek southward this morning.
Spillover will be efficient across far western NV through around 3
AM. Spillover becomes less efficient through the remainder of the
morning south of US-50 as the front loses its steam, especially
into the Eastern Sierra, which will yield lighter snow
accumulations to areas below 8000 feet. Precipitation chances
diminish across the region by sunrise, with only some isolated
light snow showers over the Sierra from the Tahoe Basin northward
expected through the remainder of the day. Westerly winds are
expected to remain elevated behind the frontal passage, with
gusts to 25-30 mph in valleys and 50-60 mph along ridgelines
possible through this afternoon.

Dry conditions don`t stick around too long, as a closed low
approaches the northern California coast early Friday morning. This
system will transport subtropical moisture into the region, with
precip bands wrapping around the parent low bringing periods of
mountain snow and valley rain as it gradually slides down the west
coast through Sunday. Snow levels fluctuate between 4500-5500 feet
through the duration of this storm, which will likely lead to
periods of difficult travel in the Sierra under heavier bands. High-
res guidance still shows a good amount of variability in the timing
of these heavier bands, which will greatly impact snow accumulations
through Sunday.

Generally, storm total snow accumulations from Friday to Sunday have
been on the upward trend for the Tahoe Basin, and generally stagnant
for the Mono County. Recent guidance suggests a 50-60% chance for
more than 12" of snow along the Sierra crest from the Tahoe Basin
northward, and a 60-70% chance for 12" of snow for the Sierra crest
in Mono County. For Sierra communities (including Truckee, South
Lake, and Mammoth Lakes), there is a 50-70% chance for greater than
6" of snow through Sunday. Overall, this doesn`t look like an overly
impressive winter storm for the Sierra, especially given the
extended duration of this storm. However, you can still expect
periods of travel difficulties in the Sierra from Friday morning
through Sunday. If your holiday weekend travels take you into the
mountains, best to leave extra time and be prepared for chain
controls.

Upper-level ridging builds into the western US behind the exiting
low by Monday, yielding much drier and warmer conditions for the
first couple days of April. This break looks short-lived yet again,
with storm chances returning as early as Wednesday, though there is
still a wide spread in possible solutions. Some scenarios keep
temperatures above average through Friday, while others indicate a
return to well-below average temperatures by Thursday. Regardless,
the storm door will be open mid-to-late next week with potential for
increased winds and shower chances into next weekend. Whitlam

&&

.AVIATION...

FL100 winds reached their peak around 50 kts between 06-09z with the
passage of a cold front through the region. Expect FL100 winds to
gradually taper through the remainder of today, though LLWS and
turbulence will continue to be a concern through this afternoon.
Surface winds become westerly this morning, with gusts 20-30 kts
expected for most regional terminals this afternoon.

Moderate-to-heavy snowfall will continue to bring IFR/LIFR
conditions to KTRK/KTVL through around 12z. Light rain showers
spilling into far western NV will continue to bring periodic MVFR
CIGS to KRNO/KCXP/KMEV through around 12z. Light snow showers ahead
of the main cold front precip band are expected to bring periodic
MVFR/IFR conditions to KMMH between 10-16z.

Precipitation chances taper off regionwide by 16z, yielding VFR
conditions for most regional terminals through the remainder of the
day. The only exception includes KTRK/KTVL, where isolated light
snow showers may bring brief lowering of CIGS/VIS between 21z-06z.
Whitlam

&&

.AVALANCHE...

The quick hitting storm is currently ongoing in the Sierra. Details
for this storm remain on track...

* Liquid totals (SWE): Generally from 1.0-1.7" for the Sierra crest
  west of Tahoe southward to Alpine County, and 0.75-1.2" for Mono
  County through this morning.

* Peak Snowfall Rates: For the Tahoe Basin, 1-2" per hour rates are
  ongoing and will continue through around 4-5 AM. For Mono County,
  1-2" per hour rates are possible in the high Sierra from 2 AM-7 AM.

* 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: Downtrending through the remainder of
  the morning, with highest gusts 50-60 mph.

Whitlam

&&

.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 11 AM PDT this morning NVZ002.

     Lake Wind Advisory from 11 AM this morning to 8 PM PDT this
     evening NVZ002-004.

CA...Winter Weather Advisory until 11 AM PDT this morning CAZ072-073.

     Lake Wind Advisory from 11 AM this morning to 8 PM PDT this
     evening CAZ072.

&&

$$


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