Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 220941
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
241 AM PDT Thu Apr 22 2021

.SYNOPSIS...

Dry weather with above average temperatures and breezy west to
northwest winds will prevail today and Friday. A late season storm
will bring sharply colder temperatures, stronger winds, and
periods of valley rain and mountain snow this weekend into early
next week. Dry and warmer conditions then return by the middle of
next week.

&&

.SHORT TERM...

Bottom line up front: The best overall outdoor activity days will
easily be today and Friday, but keep the jackets handy (and Sierra
pass drivers need to get their winter travel gear) for this
weekend as a late season winter-like storm moves in. This system
is looking to be one of the wettest for the Sierra in this modest
2020-21 winter season, excluding the late January storms.

Dry and warm spring weather conditions prevail today and Friday,
although a secondary shortwave passage across eastern NV-Utah will
kick up some increased northwest breezes this afternoon-early
evening across much of western NV. This looks to be a gradient
wind so peak gusts aren`t expected to be that strong (mainly 25-35
mph) but with a few hours of sustained winds up to 20 mph,
localized areas of blowing dust may occur downwind of favored
areas such as the Black Rock Desert and Carson Sink, including
portions of US-50 east of Fallon. On Friday as a flat ridge axis
moves into western NV, the breezes are expected to be more of the
typical zephyr variety across far western NV, with lighter wind
speeds over the dust-prone areas of west central NV. Moderate
chop up to 2 feet is expected on both Tahoe and Pyramid (possibly
approaching 3 feet near sunset/lake closure time today on Pyramid
Lake) through Friday, but overall conditions look marginal for a
lake wind advisory.

By Saturday, we will begin to feel the effects of the incoming
storm. The primary impacts will be wind-related with speeds
ramping up during the day. Peak afternoon gusts of 40-50 mph are
likely, locally stronger in wind prone areas along the
I-580/US-395 corridors from SE Lassen County and far western NV
to northern Mono County. Sierra ridge gusts may exceed 80 mph at
times from early morning to late afternoon Saturday. These
stronger winds could produce areas of blowing dust with reduced
visibility across portions of western NV and eastern Mono County.

While the main storm and the best precip chances hold off until
late Saturday night-Sunday, a leading shortwave is projected to
bring a round of lighter rain late Friday night into Saturday for
northeast CA-northwest NV, possibly extending into the Tahoe
basin. Precip amounts with this leading wave are expected to be
light (generally 0.10" or less) with minimal travel impacts
across the main Sierra passes. Some locations near the OR border
could see heavier rain totals around 0.25" early Saturday, as the
southern edge of the moisture feed from this wave brushes through.
MJD

.LONG TERM...Sunday through next week...

The late season winter storm continues to push through the region
Sunday into Monday, bringing strong winds, mountain snow and
valley rain to the region. Ensembles are trending slightly wetter
with the storm system Sunday into Monday, bringing some higher
amounts of snowfall to the Sierra than the previous forecast, most
notably higher amounts down into Mono County. Anyone with travel
plans over the Sierra between early Sunday morning through Monday
morning should be prepared for winter driving conditions and chain
controls over the passes.

Strong gusty winds continue on Sunday, mainly along and south of
I-80, with the strongest winds in Mono and Mineral counties. At
this time, there still looks to be around a 30% chance of damaging
winds for Mono-Mineral. Overall, the peak wind gusts do look to
be around 40-50 mph for those areas south of I-80, with lesser
winds for the northern areas.

The total water equivalent amounts for Sunday-Monday in the Sierra
look to be around 0.5-1.0" with up to 1.5" along the Sierra Crest.
Spillover precip into the valleys of northeastern California and
western Nevada will be limited, with generally less than 0.15"
right along the front as the main moisture plume pushes across the
Sierra.

With snow levels dropping to around 5500-6000 ft, this will bring
a couple inches of snow Sunday morning and again Monday morning
around the Tahoe Basin and Sierra valleys (with a rain/snow mix
and little additional snowfall during the daytime on Sunday). For
the higher elevations and passes above 7000 ft, precipitation
should remain all snow through the event with generally 6-12"
expected. There is a 25% chance we could see amounts up to 18"
along the Sierra Crest with a potential wetter solution from the
ensembles.

The storm system exits the region on Monday with a few lingering
light showers possible into Tuesday. Colder temperatures are
expected on Monday behind the front, with highs in the 50s for
western Nevada and 40s in the Sierra valleys. As shortwave ridging
builds back over the region Tuesday and through the end of next
week, temperatures will begin a warming trend to near or above
average. -Hoon

&&

.AVIATION...

VFR conditions will prevail through Friday with afternoon breezes
both days. Today`s winds are likely to be a touch greater than
Friday`s especially for west central NV, with sustained speeds up
to 20 kt and gusts of 25-30 kts.

A stronger Pacific storm will move into the region this weekend,
bringing stronger winds, increased turbulence with periods of
LLWS, mountain snow down to the KTVL/KTRK/KMMH terminals, and
lighter valley rain. MJD

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&

$$

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


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