054
FXUS66 KSTO 102127
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
127 PM PST Mon Nov 10 2025

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

.KEY MESSAGES...

 - Dry and warm weather continues through Tuesday
 - An atmospheric river storm system late Wednesday through Friday
   will bring widespread precipitation, gusty winds, cooler
   temperatures, and mountain snow
 - Winter Storm Watch in effect from 1 AM Thursday - 4 AM Friday
   for the northern Sierra and southern Cascades above 5000 feet
 - Potential for some additional showers over the weekend into
   early next week as a secondary system moves across the Pacific
   Northwest

.DISCUSSION...

...Today through Tuesday...
Warm and dry conditions will prevail across interior northern
California through Tuesday as upper level ridging continues across
much of the Western US. High temperatures will range from the
upper 60s to lower 70s in the mountains to the upper 70s to around
80 in the Valley, which is trending around 10 to 12 degrees
warmer than the climatological average for the middle of November.
Lowest humidity values will be in the Sierra Nevada south of
Interstate 80, around 20 to 30 percent range during the daytime.
High resolution guidance continues to show patchy fog/mist
developing Tuesday morning before sunrise and lasting through mid
morning. Confidence remains low on exact location and how dense
the fog becomes. Right now, best chances are in the southern
Sacramento Valley and the northern San Joaquin Valley Tuesday
morning.

...Wednesday through Friday...
Ensembles are in good agreement on the ridge shifting eastward
mid to late week, with a deepening trough in the eastern Pacific.
An atmospheric river storm system will approach the region
bringing along widespread precipitation, mountain snow, scattered
thunderstorms and gusty southerly winds beginning late Wednesday
afternoon. Cooler temperatures will also accompany this system
Wednesday through the end of the work week. Storm total
precipitation amounts have trended slightly higher with now 1-1.5
inches forecast across the Valley and 1 to 3.5 inches forecast in
the foothills and mountains from late Wednesday through Friday.
Slick roads and ponding water may lead to increased travel times.

While there is still some uncertainty in exact timing, snow
levels, and snow amounts, the most likely amounts of 4 to 8
inches above 5000 feet and 1 to 2 feet above pass level warrant a
Winter Storm Watch over the northern Sierra Nevada and southern
Cascades from 1 AM Thursday through 4 AM Friday. Snow levels will
initially be above 8,000 feet on Wednesday before lowering to
5,000-6,000 feet Thursday and potentially down to 4,000-5,000 feet
early Friday. Chain controls, travel delays and slick/snow
covered roads will be possible above 5000 feet from heavy snow.
There is also a 10-20% chance of thunderstorms late Wednesday
through Thursday, including the overnight period as the initial
band moves through NorCal. Showers linger on Friday but rain and
snow accumulations are much lighter by that point. Be sure to plan
ahead for the pattern change and check back frequently for
updates on the latest forecast!

...Saturday through Monday...
There is potential for another round of showers in the forecast
for later this weekend into early next week from a secondary
system moving across the Pacific Northwest. Minimal impacts are
expected from this at this time as precipitation amounts appear to
be relatively light, however there could be some minor snow
accumulations in the mountains and then slick roads elsewhere
from rain.

.AVIATION...
General VFR conditions prevail across interior northern
California over the next 24 hours, with the exception of patchy
MVFR/IFR/LIFR conditions in the Valley and Delta from 11Z to 17Z
Tuesday in BF/FG. Confidence is low on exact timing and density.
Light and variable winds are forecast through the period.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from late Wednesday night through late
Thursday night for West Slope Northern Sierra Nevada-Western
Plumas County/Lassen Park above 5000 feet.

&&

$$