Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 252245
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
245 PM PST Sat Jan 25 2020

.SYNOPSIS...

Low pressure will move through the region tonight and Sunday
bringing valley rain, mountain rain and snow, and breezy
conditions. A few inches of snowfall for Sierra passes is expected
by Sunday morning. A couple of weak storms brush the region early
next week with a ridge of high pressure expected to bring very
warm weather by the end of the week.

&&

.SHORT TERM...

There were not many substantial changes in the short term part of
the forecast this cycle. Model solutions still bring a shortwave
trough through the region late tonight and Sunday. Some of the
solutions have been wavering back and forth regarding precipitation
amounts...but since we are fairly close to the onset of this
precipitation...we leaned more on the short range high resolution
models for both POPs and QPF tonight and tried to refine the
timing a bit more. The heaviest precipitation time still looks
like the midnight to 6 am time frame with slightly increased QPF
in the Sierra.

Snow levels continue to be problematic and now appear they will
start higher this evening and may not fall quite as fast as
previously forecast. Our current forecast favors the lower end of
the range thinking heavier precipitation intensity will drag the
snow levels down late tonight. The current projection has snowfall
amounts around 3-6 inches on the Sierra passes that are open year
round while above 8000 feet in the Tahoe area some spots could
see 10+ inches of snow. Farther south into Mono County the Sierra
crest is not expected to pick up more than 4-8 inches of snow
with lesser amounts below 8500 feet.

Amounts near lake level around Tahoe may be only a couple of
inches as the rain does not change to snow until Sunday morning.
East of the Sierra precipitation amounts should drop off rather
quickly and only rain is expected in the lowest valleys.

While snow amounts in the Sierra and elsewhere will be light by
our winter storm standards...even a few inches could cause travel
disruptions late tonight and Sunday morning on the mountain roads
and highways. Travelers should take potential delays into
account.

Gusty winds are still expected with this system. Choppy conditions
are likely on Lake Tahoe and a Lake Wind Advisory remains in
effect. In the lee of the Sierra...wind prone areas could see
gusts around...or in excess of...40 mph late tonight and Sunday.

A brief break develops Sunday night into Monday as a flat ridge
moves over the region. Warm air advection near the Oregon border
could produce light precipitation early Monday north of
Cedarville. Then another fast-moving shortwave drops out of Oregon
into the Great Basin Tuesday. Model solutions are at odds with
how much...if any...precipitation can be expected with this
feature. For now we will keep any precipitation confined to the
northern half of the forecast area and mention only light
amounts.

.LONG TERM...

The main story for the long term is strengthening high pressure
over the southwest U.S. next week that will keep the storm track
mainly north of the Oregon border. While there aren`t any signs
that the building ridge of high pressure is going stay over the
region for long, there aren`t any signs of strong storms either.

Around the Wednesday night time frame, a weak system is forecast
to brush by the region with little to no impact in our area.
Mostly a slight chance of showers near the Oregon border and an
increase in cloud cover and breezes for the rest of the region.

The ridge is then forecast to build more directly over California
and Nevada going into the next weekend. Expect clear skies and
very warm temperatures for Friday and Saturday. In fact,
temperatures could be near records by Saturday with daytime highs
in the mid 60s in the valleys and upper 50s in the Sierra.
-Zach

&&

.AVIATION...

A weak storm currently moving into the region will bring minor
impacts through midday Sunday with rain in the valleys, rain
changing to snow in the mountains, and breezy winds to the
region.

For KTRK/KTVL/KMMH most of the precipitation will be rain with
snow levels coming down to terminal level late morning/early
afternoon Sunday with little to no snow accumulation expected.
MVFR conditions are likely with periods of IFR conditions
possible.

For KRNO/KCXP/KMEV impacts will mainly be lower ceilings and
occasional light rain showers along with some breezy winds with
gusts up to 20 knots.

A couple of weak brush by systems early next week will keep some
clouds in the region and slight increases in winds. A ridge of
high pressure is forecast to build over the region for the second
half of the week. -Zach


&&

.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory from 9 PM this evening to 3 PM PST Sunday for
     Lake Tahoe in NVZ002.

CA...Lake Wind Advisory from 9 PM this evening to 3 PM PST Sunday for
     Lake Tahoe in CAZ072.

&&

$$

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



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