031
FXUS66 KSTO 132148
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
148 PM PST Sat Dec 13 2025

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


.KEY MESSAGES...

 - Dry weather through the weekend, with fog, mist, and low
   clouds through the Central Valley and adjacent foothills.

 - Cooler temperatures continue below the stratus layer, with at
   or above average temperatures above the stratus layer.

 - Breezy south winds and rain/isolated thunder chances return
   early to mid week.

&&

.DISCUSSION...

...Today and Sunday...

Current visible satellite continues to show the low level
stratus, mist, and fog lingering throughout the Central Valley,
lower foothills, and Delta. The broad high pressure system
continues over the eastern Pacific and southwestern United States
through early Monday bringing the low stratus, mist, and fog.
Foggy conditions are expected during the morning and overnight
hours for the Valley and Delta, with visibility reductions of a
quarter of a mile or less. Temperatures will continue to be
affected by the high pressure system and low stratus, with well
below normal temperatures within the Central Valley and lower
foothills. Areas that are above the stratus deck are seeing at or
above normal temperatures and plentiful sunshine. This has allowed
for RH values to drop quickly in the foothills and mountains.
Little recovery during the overnight hours for RH values.
Occasional breezy conditions at times during the afternoon for
areas within the Sierra this weekend.

...Next Week...

Confidence continues to increase in a pattern change occurring
early to mid week, with wetter and breezier conditions.
Precipitation begins to shift into the coastal range and northern
Sacramento Valley late Monday and spreads east and south Tuesday
into Wednesday. Thunderstorm chances (15-25 percent) arise during
the afternoon hours on Tuesday through Wednesday for areas in the
north and central Sacramento Valley, northeast foothills and over
mountains. Snow levels will be above 8000 feet through Wednesday
and diminish toward 6500-7500 feet late on Wednesday. Little to
no snow accumulations are currently expected. Breezier conditions
are anticipated within the Sierra as the system moves through the
region. Looking ahead toward the later portions of the work week
and into next weekend, further chances for multiple upper level
waves bringing more precipitation and breezier conditions move
into the southwestern United States.

&&

.AVIATION...

Persistent low ceilings and reduced visibility across the Central
Valley and lower foothills continues throughout the TAF period
and through Sunday. Ceilings have slightly improved this
afternoon to MVFR for some sites, but will drop back to LIFR and
IFR later this evening and overnight for each TAF location.
Reductions to visibility are expected, with areas getting down to
a quarter mile or less overnight and into tomorrow mid morning.
Light and variable winds throughout the TAF period and again on
Sunday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$