472
FXUS65 KREV 242151
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
151 PM PST Sun Nov 24 2024

.SYNOPSIS...

* Active weather returns this week as a potent winter storm
  impacts the Sierra Nevada through Wednesday morning.

* The most pronounced impacts with this storm will be felt across
  portions of Alpine and Mono counties on Tuesday, with elevations
  above 7,500 feet experiencing the greatest snowfall.

* For the Thanksgiving holiday and weekend, expect generally dry
  conditions and cool temperatures.

&&

.DISCUSSION...

As the Thanksgiving holiday approaches, attention turns to an
incoming winter storm that is expected to impact the Sierra
through early Wednesday:

* While snowfall will begin across the Sierra and NE California on
  Monday, the bulk of the snow impacts with this storm are
  expected on Tuesday, particularly for Sierra areas south of
  US-50 through Mono County.

* The latest trends with this storm have continued to shift the
  axis of heaviest moisture farther southward across Mono County.
  This decreased expected snow totals across the Tahoe Basin while
  boosting snow totals across Mono County.

* Travel impacts and slow downs can be expected for any trans-
  Sierra travel. Be sure to keep close tabs on the forecast and
  check with CalTrans and NDOT for road conditions and closures
  before beginning travel.


Monday: Sierra Snow Begins, Rising Snow Levels

* Snow levels will rise through Monday afternoon with levels
  starting near 5,000 feet at day break to 6,000 7,000 feet north
  of US-50 with 7,000-8,000 feet south of US-50.

* Snow showers will be possible above these elevations with 1-3
  inches of snowfall possible across Tahoe Basin passes including
  Donner and Echo Summits. Slushy conditions are possible as
  afternoon temperature warm a few degrees above freezing.

* In Mono County, areas above 8,000 feet could see a more
  significant accumulation as as secondary stream of moisture
  targets farther southward. Snowfall amounts reaching 5-10 inches
  are possible along this Sierra crest through sunset.


Tuesday-Wednesday: Colder Phase of the Storm, Main Snow Impacts.

* The bulk of the snowfall impacts with this storm are expected
  from Tuesday into early Wednesday morning as snow levels
  steadily drop below 5000 feet by Tuesday night.

* While the greatest snow totals have shifted south across Mono
  County, the Tahoe Basin will likely experience travel impacts
  Tuesday into Wednesday morning with Sierra passes seeing a
  15-20% chance of receiving up to a foot of snowfall. Lower
  Sierra communities near lake level could see under 6 inches.

* The bulk of heavy snowfall across Mono County is expected to be
  above 7500-8000 feet through Wednesday morning. Feet of snowfall
  are expected with nearly a 70% chance of seeing over 3 feet
  along the Sierra crest. Locations below 8000 feet have lower
  confidence at this time due to snow level uncertainties.

* Western Nevada valleys will largely see a rain event with the
  main period of spillover expected late Tuesday afternoon and
  evening. Between 0.2 to 0.5 inches of rain are likely. Foothill
  areas above 5000 feet could see a few inches of snow
  accumulation by Wednesday morning.

Thanksgiving Weekend:

* Conditions improve by Wednesday afternoon with overall drier
  and cooler conditions prevailing for the balance of the week.

* Light breezes with temperatures nearly 10 degrees below season
  averages are expected on Thanksgiving day. Overall, expect
  afternoon highs in the low to mid 40s across both the Sierra
  and western Nevada with partly cloudy skies. Fuentes

&&

.AVIATION...

A lull in the weather will prevail tonight with VFR conditions
prevailing. An incoming winter storm will begin to produce
mountain wave turbulence, LLWS, and mountain top obscurations
after 12z Monday morning.

Moisture will increase through the day on Monday with -SHSN
possible across Sierra terminals Monday after 15z with rain
mixing with snow after 21z as snow levels rise between 6500-7000
across the Tahoe Basin.

More widespread snowfall impacts are expected on Tuesday into
Wednesday morning as snow levels steadily lower to near 5000 feet
Tuesday night as the bulk of the moisture drives into Mono County.
Fuentes

&&

.AVALANCHE...

A winter storm is expected to impact the Sierra from Monday into
Wednesday morning. The heaviest snowfall rates are expected on
Tuesday through Wednesday morning with the heaviest accumulations
expected south of US-50 along the Mono County crest.

* Snow levels: Snow levels will rise through Monday afternoon with
  levels starting near 5,000 feet at day break, then rising to
  6,000-7,000 feet north of US-50 and 7,000-8,000 feet south of
  US-50. Snow levels will steadily fall Monday evening through
  Tuesday before dropping below 5000 feet by Tuesday night.

* Snow totals: Monday: 1-3" along Tahoe Basin crest with 5-10"
  along the crest in Mono County. Snow totals from Tuesday into
  Wednesday morning 10-18" along the crest with a 15% chance of
  for isolated areas up to 24". Areas below 6500 feet could see
  2-6". Mono county could see 1-2 feet above 7500 feet with a 70%
  chance of seeing over 3 feet along the Sierra crest.

* SWE: 30-40% chance of at least 2" SWE along the Sierra crest in
  the Tahoe Basin Monday through Wednesday morning. 40-50% chance
  of exceeding 3" SWE on the Mono County crest during this period.

* Strong ridgetop gusts of 60-80 mph, with peak gusts over 100 mph
  in Mono County.

&&

.REV Watches/Warnings/Advisories...
NV...     Winter Storm Warning from 1 PM Monday to 4 AM PST Wednesday
     NVZ002.

CA...Winter Weather Advisory from 4 PM this afternoon to 4 AM PST
     Wednesday CAZ071.

     Winter Storm Warning from 1 PM Monday to 4 AM PST Wednesday
     CAZ072.

     Winter Storm Warning from 4 AM Monday to 4 AM PST Wednesday
     CAZ073.

&&

$$