193
FXUS66 KSTO 122156
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
156 PM PST Wed Nov 12 2025

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


.KEY MESSAGES...

 - An atmospheric river storm system will bring widespread
   precipitation, gusty southerly winds, cooler temperatures,
   scattered thunderstorms and mountain snow late tonight through
   Friday
 - Potential for some additional showers Saturday into early
   Sunday and again Sunday afternoon into early next week

.DISCUSSION...

...Tonight through Friday...
An atmospheric river storm system will bring widespread
precipitation, isolated thunderstorms, gusty southerly winds,
high-elevation Sierra snow and cooler temperatures to the
forecast area tonight through Friday. The latest guidance shows
some light showers ahead of the main band this evening with the
front moving through late tonight into Thursday. WPC Guidance
shows the latest precipitation totals to be around 1-2.25 inches
in the Valley and 1.5-3.5 inches in the foothills and mountains
(locally higher amounts are possible over the mountains). Snow
levels have trended higher with the most recent forecast, and are
expected to remain above 8000 feet through Thursday evening,
lowering to around 6500-7500 feet late Thursday night into early
Friday morning. A Winter Weather Advisory remains in effect above
7000 feet for the northern Sierra from 4 PM Thursday to 7 AM
Friday. Highest snowfall amounts are still expected south of
Highway 50. Gusty southerly winds will also develop with this
storm system, and a Wind Advisory remains in effect for the
Valley, Delta and Northeast Foothills from 10 PM tonight through 1
PM Thursday. Isolated thunderstorms may also develop on Thursday,
with generally a 10-20 percent chance being advertised by the
NBM. Isolated embedded thunderstorms will be possible as the main
frontal band move through. Be sure to plan ahead for wet weather
and check back frequently for updates on the latest forecast!

...Saturday through Sunday Morning...
A weaker wave of precipitation will bring light precipitation
Saturday into Sunday morning, with best chances south of I-80.
Minimal impacts are expected from this at this time as
precipitation amounts appear to be light, with less than 0.10
inches north of I-80 and 0.10-.50 south of I-80. There could be
some minor snow accumulations in the Sierra south of Highway 50,
with 1-2 inches expected.

...Sunday PM through Early Next Week...
There is potential for another round of showers in the forecast
for Sunday afternoon into early next week from another system
moving across the Pacific Northwest. WPC Guidance shows the
latest precipitation totals to be around 0.25-0.50" in the Valley
and 0.5-1" in the foothills and mountains. This system appears to
be somewhat colder, with snow levels potentially lowering to
around 5500-6500 feet by Monday morning.

.AVIATION...
Scattered MVFR conditions due to low clouds as a weather system
makes its way into the region. South winds will stay generally 12
kts or less until 09Z Thursday. South winds will then increase
with gusts 30 to 45 kts through the Valley and gusts to 50 kts in
the Delta from 09Z Thursday to 00Z Friday. MVFR/IFR/LIFR
conditions anticipated after 12Z as rain moves into the region.
Over the mountains snow levels will be above 7000 feet with
southwest winds gusting 35 to 45 kts 06Z to 21Z Thursday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 10 PM this evening to 1 PM PST Thursday for
Carquinez Strait and Delta-Central Sacramento Valley-Northeast
Foothills/Sacramento Valley-Northern Sacramento Valley-Northern
San Joaquin Valley-Southern Sacramento Valley.

Winter Weather Advisory from 4 PM Thursday to 7 AM PST Friday
for West Slope Northern Sierra Nevada.

&&

$$