Somerset, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

573
FXUS66 KSTO 231320
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
520 AM PST Mon Dec 23 2024

.SYNOPSIS...
Periodic chances for moderate precipitation and breezy to gusty
southerly winds are expected to continue through the weekend as a
series of weather systems impacts the region. Isolated
thunderstorms possible on Tuesday.

.DISCUSSION...
Current radar imagery shows a few lingering light showers early
this morning, mainly over the Sierra and east side of the Valley.
Otherwise, generally drier conditions are anticipated today ahead
of the next storm. Patchy Valley fog is possible this morning
across portions of the Valley and Delta.

A stronger, colder system is still on track to impact interior
NorCal Monday night into Tuesday. Current probabilities of
exceeding 1 inch of liquid precipitation are around 70-100% across
the northern Sacramento Valley, foothills and mountains. Forecast
precipitation totals sit around 0.5-1" across the Valley, with
1-2.5 inches possible along the Sierra/southern Cascades and
foothills. Snow levels will start above pass levels, but rapidly
lower to around 5000-6500 feet by Tuesday morning. NBM advertises
a 60-90% probability of exceeding 6 inches of snowfall through
Tuesday evening. Moderate mountain snow is expected, with snowfall
rates up to 1-2.5" per hour possible Tuesday morning. A Winter
Weather Advisory remains in effect for the southern Cascades and
northern Sierra for elevations above 6000 feet from 7 AM to 7 PM
Tuesday. Total snow accumulations of 5 to 10 inches are forecast
above 6000 feet; locally higher amounts over peaks. Additionally,
NBM depicts a 10-20% probability of thunderstorm development on
Tuesday. Isolated thunderstorms will be possible along the main
frontal band, and also behind the front with some possible
clearing. Gusty southerly winds are also anticipated late Monday
night through Tuesday morning as the system moves through, with
gusts up to 25-35 mph over the northern Sacramento Valley and
northeast foothills; stronger gusts over the Sierra.

Precipitation chances are expected to taper off Tuesday night,
with overall dry conditions anticipated for much of Wednesday
(Christmas Day) as short-lived ridging moves overhead. With a
drier period expected to follow, additional chances for fog
development will likely be possible (10-20% probability of
visibilities less than 1 mile).

Ensembles indicate an active pattern continuing through the
weekend. The next wave is expected to arrive late Wednesday night
or early Thursday, bringing another round of widespread
Valley/foothill rain and mountain travel impacts. Snow levels will
start around 4500 to 5500 feet early Thursday, then increase to
around 5500-6000 feet by Thursday afternoon. Moderate snow is
possible, with probabilities of snowfall exceeding 6 inches above
6000 feet ranging from 40% to 70% through Thursday night. Breezy
southerly winds will accompany the system.

Please continue to check weather.gov/sto for the latest updates
and check quickmap.dot.ca.gov before you go this holiday season!


.EXTENDED DISCUSSION (Friday THROUGH Monday)...
While uncertainty remains, ensembles suggest an active pattern
persisting late week into the weekend as additional waves move
across the area. Probabilities of liquid precipitation exceeding
0.5 inches range from 40% to 60% across the Delta and southern
Sacramento through Sunday night, while probabilities of exceeding
1 inch around 60% to 95% favor the northern Sacramento Valley,
foothills and mountains. Probabilities of snowfall exceeding 6
inches above 6000 feet through Friday evening sit around 20% to
50% at this time, with minor to moderate mountain travel impacts.
Snow levels start around 6000 feet Friday morning, then rise above
pass levels by Saturday. Drier conditions may return by early
next week.

Please continue to check weather.gov/sto for the latest updates
and check quickmap.dot.ca.gov before you go this holiday season!

&&

.AVIATION...
MVFR/IFR with localized LIFR conditions from low ceilings and
lingering precipitation south of I-80 and near KRDD/RBL through
18z Mon with continued IFR/LIFR conditions across the Northern
Sac. Valley and mountains from 00z Tue through 12z Tue as light to
moderate precip. develops. Light southerly winds less than 12 kts
expected until 00z Tue, then 15-30kt gusts through the Valley
with 35-45 kts along the Sierra crest after 09z Tues. Snow levels
around 6500-7500 feet, becoming 8000-9000 feet after 00z Tue. &&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 7 AM to 7 PM PST Tuesday for West
Slope Northern Sierra Nevada-Western Plumas County/Lassen Park.

&&

$$