Olympic Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

194
FXUS65 KREV 192252
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
252 PM PST Fri Dec 19 2025

.KEY MESSAGES...

* Widespread strong winds today and again on Sunday. Likely impacts
  for both road and air travel. Localized fire weather concerns in
  the Eastern Sierra this afternoon.

* Rain showers and high elevation snow showers this afternoon and
  evening. Heavier rains likely Saturday night through Monday that
  could lead to localized flooding concerns.

* Another storm or two could bring significant rain and snow
  Tuesday into Christmas Day, but confidence in the details
  remains mixed.

&&

.DISCUSSION...

Key Message 1: Winds today will be an issue for anyone traveling
by air or on the road. Peak winds will be before 4 PM, then taper
off throughout this evening. Expect wind prone areas along US-395
to experience gusts up to 75 mph, otherwise other locations along
the Sierra Front, Tahoe, eastern Sierra, and NE CA will see gusts
of 55-60 mph. For that reason, we will be maintaining our Wind
Advisory for NE CA and western NV and our Lake Wind Advisory for
Pyramid Lake through this evening. Isolated critical fire weather
conditions will be seen today across the eastern Sierra and into
western NV near S. Lyon County due to a combination of low RH and
gusty winds. More on this in the fire weather section further
down. Tonight through Saturday, the 700mb jet weakens a bit while
keeping Sierra ridges breezy in the 60-70 mph range. Then by
Sunday afternoon, the 700mb jet will increase again, pushing
75kt. Those winds will mix down and we`ll be looking at more
strong winds in much of the same areas as today at similar
magnitudes.

Key Message 2: Rain showers have entered our CWA this morning and
have now moved into the Tahoe Basin. Current rates are 0.05-0.1"/hr
along the Sierra and into NE CA. We expect those rates to persist
overnight and into Saturday afternoon before the precip intensity
picks up slightly Saturday evening. Through Saturday afternoon
there`s a 60-70% chance of at least 1" of rain along the Sierra
crest, a 50-60% chance of at least 0.4" in the foothills, and a 60%
chance of 0.1" along the Sierra Front and Eastern Sierra. Snow
levels will continue to hover around 8-9 kft tonight through
Saturday afternoon.

Another wave of precip is expected to move through Saturday evening
through Monday evening, bringing heavier rain rates while
maintaining similar snow levels of 8-9 kft. Current blended guidance
has a 48 hour rain total of 4.5-5.5" from Tahoe northward along the
Sierra. Lower Sierra valleys and NE CA have a 70-80% chance of at
least 2.5", and 50-60% chance of at least 1.5" along the Sierra
Front and eastern Sierra. Spillover will be limited during this
time, except for northern Washoe County where they could see as much
as 1.2". Because of these rain totals, we have issued a Flood Watch
for the Tahoe Basin northward up through Lassen County for Sunday
through Monday. More details on that in the Hydrology section.

Key Message 3: From Tuesday onward through Friday next week there`s
a moderate (50-60%) chance of multiple cooler storms rolling
through. Cooler air will get brought in on the back side of a low
pressure system off the coast, lowering snow levels down to
5000-7000 ft by Christmas Day. GFS and EC ensembles are showing a
rather significant 500mb height anomaly over the eastern Pacific
next week and signs for impressive snowfall. Looking at CW3E`s
GEFS IVT plume, there`s a well-defined swath of moisture headed
towards our range of latitudes next week, which further increases
forecaster confidence. So while it`s less uncertain we`ll have a
white Christmas this year (at least up in the mountains), the
exact details of intensity, location, and duration remain to be
determined.

-Justin

&&

.AVIATION...

* Strong W/SW flow with 700mb winds peaking over the Tahoe Basin
  at 60 kt this evening. Many peak gusts have already been
  observed today, though strong winds will continue through this
  evening. Gusts of at least 35 kt likely for Sierra terminals and
  along the Sierra Front. High-end gusts over 50 kt cannot be
  ruled out in more wind prone areas along Hwy 395. NBM has 40-60%
  chances of 50 kt peak gusts at RNO and MMH for example. Another
  round of strong winds is looking likely on Sunday as well with
  similar magnitudes.

* With that front today, rain showers have developed this
  afternoon and will persist through tonight. Mainly in the
  mountains from SVE to TRK/TVL with potential for MVFR-IFR
  conditions in rain. For RNO/CXP/MEV, light showers are possible
  (40% chance) but visibility/ceilings look to remain VFR. MMH
  misses out on this one, just wind for them.

* Additional showers possible Saturday but mainly light
  intensity. Winds should be less robust as well.

-Chris/Justin

&&

.FIRE WEATHER...

* Areas of critical wind and low humidity are of concern in the
  Eastern Sierra today, specifically fire weather zones CA274 and
  NV421.

* Latest NBM and HREF guidance suggest 1-3 hours of critical
  conditions especially along Hwys 395 & 6 where W/SW winds could
  gust over 50 MPH this afternoon (see Wind Advisory) and RH
  values around 20%.

-Chris/Justin

&&

.HYDROLOGY...

Moderate to heavy rains will lead to significant rises on rivers and
streams Sunday into Monday most notably from Alpine County north
through Lassen County.

Minor flooding of small streams, urban and poor drainage areas and
rockfall in steep terrain are possible during any prolonged periods
of high intensity rainfall.

While no mainstem river flooding is currently forecast, The Susan
River near Susanville and the West Fork of the Carson near Woodfords
are currently expected to exceed action stage and minor flooding can
not be ruled out in these area. Remain aware of the potential for
additional river and stream rises near Christmas Eve in large
mountain drainages below about 6000 feet like the Susan River. In
these areas additional rain and saturated conditions could lead to
fast rises and renewed flooding concerns. In other areas,
lowering snow levels will reduce flooding concerns into next week.

Enhanced runoff and sediment transport are likely below recent burn
areas, but debris flows are not expected. Watch for additional rises
near Christmas Eve and possible flooding concerns especially in
drainages with large mountain drainages below about 6,000 feet, like
the Susan River for example.

You can find river forecasts updated twice daily at:
www.cnrfc.noaa.gov

-Tim

&&

.REV Watches/Warnings/Advisories...
NV...Wind Advisory until 4 AM PST Saturday NVZ002-003-005.

     Flood Watch from late Saturday night through Monday afternoon
     NVZ002.

     Lake Wind Advisory until 4 AM PST Saturday NVZ004.

CA...Wind Advisory until 4 AM PST Saturday CAZ070>073.

     Flood Watch from late Saturday night through Monday afternoon
     CAZ071-072.

&&

$$