Winter Weather in Nevada, March 10, 2021

Area Forecast Discussion
National Weather Service Reno NV
253 PM PST Tue Mar 9 2021

.SYNOPSIS...

Low pressure will provide deteriorating travel conditions tonight
across the Sierra as accumulating snows are expected through
Wednesday. Travel impacts due to light snow are also expected in
far western Nevada valleys Wednesday morning. Chilly temperatures
with scattered snow showers are expected Wednesday afternoon
through Thursday before drier and warmer weather returns Friday
and Saturday.

&&

.SHORT TERM...

Precursor snow showers are beginning to push their way across the
Sierra and through far NE California ahead of an incoming winter
storm expected tonight into Wednesday. Travel conditions across the
Sierra will steadily deteriorate this evening before the heaviest
snowfall rates of around 1-2" per hour arrive after about midnight
until around sunrise Wednesday.

Snow amounts remain steady with about 4-8" through the Tahoe Basin
with higher-end amounts of 6-10" possible for the west shore of
Lake Tahoe. For the Sierra crest from western Plumas south into
Mono County, 8-16" inches looks possible, with 1-4" for communities
along US-395 in in Mono County and 3-6" around June Lake and Mammoth
Lakes. Little to no accumulation expected east of US-395 into Chalfant
Valley.

For western Nevada valleys, should see some good potential for
accumulating snows late tonight into early Wednesday morning which
may result in some travel headaches for the morning commute.
Accumulations down on the valley floor look to be around an inch
with about a 35% chance of getting up to 2 inches. Areas above
5000 feet including Reno North Valleys, Carson City foothills, and
Virginia City/Highlands could see up to 3-4 inches.

As the cold core of the low drifts across the region Wednesday
afternoon, we will see instability increasing with snow showers
becoming scattered and more hit and miss with brief periods of
light/moderate snowfall. Increased instability may yield snow
pellet showers along with about a 10% for some isolated lightning
strikes in the Sierra.

Snow showers will taper off Wednesday evening but may see a
deformation wrap around snowband develop from roughly I-80 southward.
A few snow showers look possible although accumulations look
limited. Expect brisk northerly breezes and below average temperatures
(30s for Sierra valleys and 40s for the valleys of western Nevada)
behind the cold front. Fuentes

.LONG TERM...Friday through next Tuesday...

With this week's closed low finally exiting southern CA-NV, drier
conditions will return Friday through much of the weekend. Brisk
north to northeast flow with stronger gusts over Sierra ridges on
Friday will keep temperatures on the cool side, with highs only in
the upper 40s-lower 50s for lower elevations and 30s to lower 40s
for Sierra valleys. These winds decrease Saturday as a ridge axis
moves inland from the CA coast with temperatures rebounding to near
mid-March averages in the 50s for lower elevations and 40s to
around 50 for Sierra valleys.

Sunday, and especially by Monday, the forecast confidence in wind,
precipitation, and temperatures falls off big time. The issue is
where the next piece of energy off the Pacific winds up and whether
or not it stays intact or starts to elongate and drop well south as
it moves into California and Nevada. Looking at how ensembles are
clustered for Monday, let's just say that they are all over the
place which leads to low confidence for early next week; also,
consider that the forecast values early next week are a broad
average and could vary considerably from what is shown at this time.

Wind-wise for Sunday, many solutions are rather breezy but only
about 10% of the EPS members and a very small number of GEFS
members are showing a situation that would require any advisories
or warnings. As far as temperatures, for Sunday in Reno they could
be anywhere from mid 40s to lower 60s and, for Monday, between the
upper 30s and 60-ish. Finally, precipitation-wise Sunday night and
Monday, POP remains on the low side given the wide variety of
ensemble solutions and very low confidence. What does all this mean?
We, and you for that matter, will have to wait until we get a bit
closer to Sunday and Monday before we can come up with an actionable
forecast!

Beyond Monday, there aren't any strong signals for a significant
storm next week although some scenarios leave open the possibility
for a weaker trough passage in the mid-late week time frame.
-Snyder/MJD

&&

.AVIATION...

Two disturbances will move over eastern CA and western NV between
this afternoon and late morning Wednesday. By late afternoon and
early evening conditions will worsen for northeast California and
the Sierra north of Mono County with the first wave, with Mono
County and areas out into far western NV to see degrading conditions
between 09Z/1 AM and 14Z/6 AM Wednesday as the more substantial
second wave moves overhead.

Widespread terrain obscuration and MVFR/IFR conditions are likely
for northeast CA and Sierra terminals tonight through Wednesday
morning; however, there may be a break between this evening and
early Wednesday morning where conditions improve slightly,
especially away from the Sierra crest. Several inches of snowfall
are likely for Sierra terminals through Wednesday morning, with up
to 2" for northeast CA terminals. Periods of MVFR/IFR conditions are
likely to reach far western NV terminals towards daybreak Wednesday
with at least light (~0.5") accumulations expected; there is a 30-
50% chance for 2", with the highest chances west of I-580/Hwy 395
and in the North Valleys of Reno (including KRTS). Widespread light
snow is expected to break by ~18Z/10 AM with a chance of -SHSN the
rest of the day; however, paved surfaces in valleys are unlikely to
see accumulations after 10 AM.

Farther east into west-central NV including KLOL, KNFL, and KHTH
chances for measurable snowfall or prevailing sub-VFR conditions
through Wednesday is low. The best bet for briefly lowered CIGS/VIS
and terrain obscuration may be in the afternoon with -SHSN.
-Snyder

&&

.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 7 PM PST Wednesday NVZ002.

     Winter Weather Advisory from 1 AM to 10 AM PST Wednesday NVZ003.

CA...Winter Weather Advisory until 7 PM PST Wednesday CAZ071.

     Winter Weather Advisory until 7 PM PST Wednesday CAZ073.

     Winter Weather Advisory until 7 PM PST Wednesday CAZ072.

&&

For more information from the National Weather Service visit...
http://weather.gov/reno