Calpine, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

236
FXUS65 KREV 150846
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
1246 AM PST Mon Dec 15 2025

.KEY MESSAGES...

* Dry weather, light winds, and unseasonably warm temperatures
  continue through Monday.

* Hazy skies and minor reductions in air quality possible each
  morning across lower urban valleys along with patchy freezing
  fog in Sierra basins.

* A pattern change is expected on Tuesday, bringing increased
  winds and chances for precipitation, primarily to the Sierra
  and northeast California.

&&

.DISCUSSION...

Generally dry weather, light winds, sunny to partly cloudy skies and
unseasonably warm temperatures continue today. A few exceptions
will occur over the central Sierra, where fog and freezing fog
persists for one more morning. Also hazy conditions are expected
over western NV due to strong valley inversions in the morning.
This foggy and hazy pattern should mostly end today as stronger
winds are expected on Tuesday. This evening there are some slight
chances for rain in portions of NE CA, amounts if any will be very
light per the HREF.

The weather pattern finally changes by Tuesday. The upper ridge
that has affected us for over a week is finally pushed down by
an upper trough in the PacNW leading to zonal flow. Winds increase
on Tuesday, primarily over mountain ridges with these stronger
winds descending into the valleys by Wednesday morning. There is a
30-70% chance of observing gusts from the west/west-southwest greater
than 45 mph on Wednesday per NBM guidance. The higher chances for
mountains ridges and wind prone areas. The strongest winds of this
week will be on Wednesday and Friday, with Friday having similar
gusts with the next shortwave trough. The stronger winds bring
elevated fire concerns for the lower elevations of Mono County.

Precipitation chances increase on Tuesday into Wednesday,
especially from the Sierra to NE CA. This area has a 50-70%
chance of precipitation with amounts ranging from 0.20-1.00 inch
of rain (the higher amount would be near the Sierra crest).
Spillover into western NV and Mono County appears to be minimal
with POPs remaining mostly around 20-50% for rainfall amounts of
less than 0.10 inches. Snow levels are high at 9-9.5 kft, so snow
is limited to the highest peaks.

The next shortwave arrives on Friday bringing more chances for
valley rain and mountain snow (above 7.5-8.5 kft), increased
winds, and cooler temperatures. The affected areas look quite
similar to the mid-week system. From Saturday and beyond, the
trend shows the wet pattern persisting with periods of
precipitation and increased winds. However, confidence is low due
to a large degree of uncertainty among the ensemble members.

-HC

&&

.AVIATION...

Generally VFR conditions persist through Tuesday morning. Periods
of IFR/LIFR conditions from KTRK to KTVL due to FG/FZFG in the
overnight and morning hours slowly clearing in the afternoon. Plus
slantwise VIS reductions over western NV in the morning slowly
clearing in the afternoon too. Winds will be generally light (AOB
8 kts) and VRB across all terminals.

Conditions start to deteriorate by Tuesday PM due to stronger
winds aloft bringing turbulence and LLWS concerns.

-HC

&&

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

$$