504
FXUS66 KSTO 012133
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
133 PM PST Thu Jan 1 2026

For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.

.KEY MESSAGES...

 - Generally light rain and high elevation mountain snow showers
   forecast through early Friday morning. Isolated thunderstorms
   this afternoon, mainly from I-80 southward.

 - Brief break Friday morning ahead of a stronger system that will
   bring moderate to heavy precipitation, gusty winds, and
   thunderstorm chances late Friday and into the weekend.

 - Unsettled weather pattern continues into next week.

&&

.DISCUSSION...

...Today - Friday Morning...
Radar imagery shows scattered showers and a few isolated
thunderstorms across portions of interior NorCal this afternoon.
Additional precipitation amounts will range from less than 0.1 to
around 0.5" in the Valley, with 0.5-1.5" over the foothills and
mountains through Friday morning. Highest amounts at higher
elevations. Additional light snow accumulations are forecast
today, highest amounts south of Highway 50 over the highest peaks.
Snow levels remain above 8000 feet through this afternoon,
lowering to around 6500-7500 feet this evening into early Friday
morning. Isolated thunderstorms are expected in the Valley and
Sierra foothills through this afternoon, mainly south of I-80
(10-20% probability). Precipitation coverage decreases later this
evening into the overnight hours, with showers limited to the
northern Sacramento Valley and adjacent terrain by early Friday
morning. A brief break in precipitation is expected for most areas
by Friday morning ahead of the next system.

...Friday PM through Monday...

The main synoptic level system over the Pacific moves toward the
coast on Friday bringing sufficient moisture and instability
toward the region. Precipitation overspread the region Friday
afternoon through the weekend and continuing into the early part
of next week. Heaviest precipitation is currently expected late
Friday through early Monday morning. Moderate to heavy rainfall is
anticipated at times, with forecasted precipitation amounts
ranging from 1-3" in the Valley, 3-5" in the foothills, and
4-6+" in the mountains. Thunderstorm chances increase Saturday and
Sunday, with the highest thunderstorm probabilities in the
Valley. Heavier rainfall rates can be expected with any
thunderstorms that develop.

As the system moves onshore, colder air will push down from the
north helping drop snow levels. Snow levels remain around
6500-7500 feet Friday PM into Saturday morning, then drop off
toward 5000-6000 feet Saturday afternoon into Sunday. Total
snowfall accumulations of 6-12 inches are expected above 5000
feet, with 2 to 4 feet above 6000 feet (locally higher amounts at
peaks). A Winter Storm Warning is in effect for the southern
Cascades and Sierra above 5000 feet from 10 PM Friday through 4 PM
Monday. Locally higher amounts are possible at higher elevations.
Winds could gust as high as 55 mph will cause dangerous travel
conditions combined with the heavy snow. If you plan to travel
this week and into the weekend, make sure you have alternate
routes, backup plans, and carry a safety kit with you at all
times.

Along with the precipitation there will be gusty south to
southwest winds through the Valley and in the mountains. Gusts up
to 35-45 mph are anticipated Friday night through early Sunday
morning for areas within the northern/central Sacramento Valley
and northeast foothills. A Wind Advisory has been issued for those
areas from 10 PM Friday through 4 AM Sunday; strongest from Chico
northward.

...Tuesday through Mid-Week...
Long range guidance looks to continue the feed of moisture and
instability into the region mid next week bringing further
precipitation and mountain snow.

&&


.AVIATION...
Light rain showers forecast for Valley TAF sites today, with
visibilities fluctuating between 2SM and 6SM. Surface wind gusts
generally below 15 knots through the day for Valley TAF sites,
wind gusts up to 30 knots in the higher elevations. Low ceilings
in combination with -RA and BR will keep most TAF sites in MVFR to
IFR conditions today. Snow levels above 7500 feet through 00z
Friday; then falling to around 6500 feet by 12z Friday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 10 PM Friday to 4 AM PST Sunday for Central
Sacramento Valley-Northeast Foothills/Sacramento Valley-Northern
Sacramento Valley.

Winter Storm Warning from 10 PM Friday to 4 PM PST Monday for
West Slope Northern Sierra Nevada-Western Plumas County/Lassen
Park.

&&

$$