Mammoth Lakes, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

755
FXUS65 KREV 260758
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
1258 AM PDT Mon Oct 26 2026

.KEY MESSAGES...

*   Gusty southwest winds are expected today, with widespread
    valley gusts of 30-40 mph and Sierra ridgetop gusts
    potentially reaching 70-80 mph.

*   Isolated light rain and mountain snow showers are possible
    across far northeast California today. Most other areas will
    remain dry through Wednesday.

*   Increasing chances for unsettled weather, cooler temperatures,
    and widespread precipitation are expected late week into the
    weekend.

&&

.DISCUSSION...

An upper-level trough currently moving onshore across the Pacific
Northwest will clip northern California and western Nevada today.
This system will be the primary driver for gusty southwest winds
across the region. Sierra ridgetop winds are forecast to increase
significantly overnight, reaching 70-80 mph by early morning,
and potentially up to 90 mph along the highest peaks. Valley
locations will experience southwest gusts up to 30-40 mph, with
wind prone areas along US-395 from Susanville down through Mono
County reaching 45-55 mph. These winds will create hazardous
boating conditions on area lakes, prompting Lake Wind Advisories
through this afternoon. Winds will gradually diminish this evening
as the trough moves eastward.

Precipitation chances associated with this system will be very
limited and confined to the Warner Mountains, Surprise Valley,
and far northern Washoe County. The chance of light rain and snow
today is around 25-35%. Along the northern half of the Warners in
eastern Modoc County, there`s around a 50-60% chance of 1" or
more of snow. Elsewhere along that range, there`s only a trace of
snow expected. Otherwise, conditions are expected to remain dry
across western Nevada and northeast California.

By Tuesday and Wednesday, a transient upper-level ridge will build
over the Great Basin, leading to a return of dry and mild
conditions. Skies will be mostly sunny, and winds will be light.
Temperatures will be near to slightly above seasonal averages,
with highs in the 50s and 60s for most areas. Overnight lows will
remain cool, generally in the 20s and 30s for the Sierra and
colder valleys, and 30s to low 40s elsewhere.

By Friday, active weather will pop back into the forecast with a
deep Pacific NW low churning off the coast of Washington.
Precipitation chances will increase, particularly for the Sierra
and northeast California, with slight chances (15-30%) for rain
and mountain snow showers. Confidence increases further for more
widespread precipitation Saturday and Sunday. Long range models
start to diverge in the exact evolution of the western trough
(consolidated upper low vs. elongated trough), which will impact
the finer details of QPF and timing. However, the overall trend
points to a series of low pressure systems moving through the
region into early next week. This will bring additional chances
for valley rain and mountain snow showers to most of the forecast
area, with snow levels likely dropping. Extended outlooks
continue to lean wetter and cooler than average conditions into
the first week of November.

-Justin

&&

.AVIATION...

VFR conditions continue today, however, an incoming low pressure
system will bring mountain wave turbulence, LLWS, and lenticular
clouds to the Sierra and east of the Sierra, starting this morning
through this evening. Southwest gusts across the Sierra and
Sierra Front will range from 25-35 kt mainly between 18Z-03Z this
afternoon. Winds will taper off late tonight, becoming light.

-Justin

&&

.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory from 10 AM to 6 PM PDT Monday NVZ003-004.

     Lake Wind Advisory from 4 AM to 6 PM PDT Monday NVZ002.

CA...Lake Wind Advisory from 10 AM to 6 PM PDT Monday CAZ071-073.

     Lake Wind Advisory from 4 AM to 6 PM PDT Monday CAZ072.

&&

$$