Fallen Leaf, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

580
FXUS65 KREV 161025
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
225 AM PST Tue Dec 16 2025

.KEY MESSAGES...

* Chances of rain and high elevation Sierra snow increase across
  the Sierra and western Nevada Tuesday afternoon into Wednesday.

* Gusty winds will impact recreation and travel on Wednesday along
  with elevated fire concerns in southern Mono County.

* Periods of gusty winds, rain and mountain snow are likely late
  this week into early next week.

&&

.DISCUSSION...

The much-anticipated pattern change is beginning to unfold across
the southwestern US, as broad upper-level ridging begins to dampen.
This will allow a series of disturbances to impact the region,
bringing chances for precipitation and gusty winds, especially in
the Sierra and NE CA. Unseasonably warm temperatures will persist
through early next week.

The first upper trough approaches on Tuesday afternoon, leading
to increasing cloud cover. Slight chances for light rain will
develop across the Sierra and northern NV/CA by late afternoon,
with NBM POPs increasing to 20-40% for these areas. Winds will
generally remain light through the day, becoming west around 10
mph in the afternoon.

Tonight, precipitation chances increase significantly across the
Sierra and northern NV/CA to 70-80%+. The Sierra Front will see a
chance of rain with lower probabilities 40-50%. Snow levels are
expected to remain around 9-10 kft, confining snow to the highest
peaks. The 00Z sounding indicated a wet-bulb zero height around
9500 ft, supporting these high snow levels. Winds intensify tonight,
especially along Sierra ridges, with gusts potentially reaching
advisory levels at lower elevations. Therefore, we decided to go
ahead an issue Wind Advisories for the Sierra, NE CA, and much of
western NV.

On Wednesday, the upper trough brings more rain chances for the
Sierra and northern NV/CA, and gradually taper off by the afternoon.
Strong and gusty southwest to west winds will be the primary
concern. Ridge gusts could exceed 80 mph in the Sierra, with
valley gusts of 35-45 mph, and wind prone areas up to 55 mph.
These winds could lead to choppy lakes and travel impacts,
particularly along north-to-south oriented roadways.

By Wednesday night into Thursday, conditions try to dry out as the
trough exits. However, by Friday, a second trough brings renewed
chances for rain and mountain snow. NBM guidance shows probabilities
ranging from 20-65% across the area. Snow levels are expected to
remain relatively high, generally above 7-9 kft. Gusty winds are
also likely, though not as strong as Wednesday`s event.

The weekend is forecast to remain unsettled, with continued periods
of rain and mountain snow. Ensemble guidance indicates higher
precipitation probabilities this weekend, especially on Sunday. Snow
levels will fluctuate but remain quite high. This active pattern
could lead to holiday travel disruptions leading up to Christmas.

-HC

&&

.AVIATION...

Periods of patchy FG/FZFG continue to be the main concern for
Tahoe terminals early this morning. Otherwise, VFR conditions
persist through this afternoon. Periods of MVFR conditions are
likely after 00Z at most terminals due to light rain reducing
CIG/VIS. For KTRK/KTVL IFR to LIFR conditions are possible
through Wednesday afternoon. Watch out for mountain obscurations
areawide.

Gusty winds are likely after 03Z in Sierra ridges. Winds continue
to increase through the night and start affecting Sierra valleys
and western NV between 06Z-12Z. Winds start to decrease by 00Z
Thursday. Mountain wave turbulence and LLWS is very likely
through this timeframe too.

-HC

&&

.REV Watches/Warnings/Advisories...
NV...Wind Advisory from 10 PM this evening to 4 PM PST Wednesday
     NVZ002>005.

CA...Wind Advisory from 10 PM this evening to 4 PM PST Wednesday
     CAZ070>072.

&&

$$