942
FXUS66 KSTO 132036
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1236 PM PST Thu Nov 13 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 continue to bring
   widespread precipitation, gusty southerly winds, cooler
   temperatures, isolated to scattered thunderstorms and mountain
   snow through Friday
 - Potential for some additional light rain and snow showers
   Saturday into early Sunday, particularly I-80 southward
 - A colder weather system will bring Valley rain and mountain
   snow Sunday PM through Monday.

.DISCUSSION...

...Today through Friday... An atmospheric river storm system will
continue to bring widespread moderate to locally heavy
precipitation, isolated/scattered thunderstorms, gusty southerly
winds, and light high-elevation Sierra snow through Friday. The
latest guidance shows some heavier precipitation moving across the
area this afternoon into the evening. A Flood Advisory remains in
effect until 7 PM across portions of the Sacramento Valley,
northern San Joaquin Valley, Delta, and Sierra foothills.
Potential impacts include minor flooding in low-lying and poor
drainage areas as well as mud/rock slides in the foothills. WPC
Guidance shows additional precipitation totals to be around
0.50-1.5 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 are expected to remain above 8000 feet
through tonight, lowering to around 7000-7500 feet by Friday
morning. A Winter Weather Advisory remains in effect above 7000
feet for the northern Sierra from 4 PM Thursday to 10 AM Friday.
Highest snowfall amounts are still expected south of Highway 50.
Gusty southerly winds are expected through this afternoon, 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 today, with generally a
10-30 percent chance being advertised by the NBM (mainly south of
I-80). Isolated embedded thunderstorms will be possible as the
main frontal band move through. Activity will become less
widespread on Friday, with best shower chances over the mountains.

...Saturday through Sunday Morning...
Light showers are expected Saturday into Sunday morning as an
upper low pushes northward. Minimal impacts are expected from
this at this time, with less than 0.25 inches north of I-80 and
0.25-1" south of I-80. There could be some minor snow accumulations
in the Sierra south of Highway 50, with 1-3 inches expected above
7500 feet.

...Sunday PM through Early Next Week...
There is potential for another round of light to moderate
precipitation late Sunday into Monday as colder weather system
drops down from the north. WPC Guidance shows the latest
precipitation totals to be around 0.25-0.50" in the Valley and
Delta, with 0.5-1.25" in the foothills and mountains. This system
will be colder, with snow levels around 7000 feet late Sunday,
potentially lowering to around 5500-6000 feet by Monday morning.

...Mid to Late Next Week...

Drier conditions are expected Tuesday through Wednesday morning.
Then, another colder system may approach the region late week.


.AVIATION...
MVFR/IFR conditions due to low clouds and rain as a weather
system pushes through the area. South winds gusting 20 to 35 kts
over the Valley and foothills until 03Z, lingering gusts 15 to 20
kts will still be possible until 08Z Friday. Additionally there is
a 15 to 25% chance of thunderstorms mainly along I-80 southward
until 09Z Friday. After 10Z, surface winds generally 12kts or
less. Over the mountains, southwest winds gusting 20 to 30 kts
until 12Z Friday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 6 PM PST this evening 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 this afternoon to 10 AM PST
Friday for West Slope Northern Sierra Nevada.

&&

$$