243
FXUS66 KSTO 142158
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
158 PM PST Sun Dec 14 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 much of Monday, with fog, mist, and low
   clouds for the Central Valley and adjacent foothills.

 - Cooler temperatures will continue below the stratus layer,
   with above normal temperatures above it.

 - Breezy south winds and rain/isolated thunderstorm chances
   midweek.

 - Active weather pattern continues end of the week and into next
   weekend.

 &&

.DISCUSSION...

...Today and Monday...

Current satellite continues to show the low stratus deck across
the Central Valley and adjacent foothills. A few areas in the
northern Sacramento Valley have gotten clouds to clear out and
temperatures to warm. This is not the case for other areas within
the Valley. This lingering stratus deck is thanks to ridge of high
pressure over the eastern Pacific and southwestern CONUS.
Temperatures underneath the stratus have been well below normal,
and areas above the stratus continue to be at or above normal.
This will continue into Monday as winds remain light and the upper
level wave moving into the region slows and reaches CA by
Tuesday. Look for continued low ceilings, mist, and foggy
conditions through Monday. Fog may become dense overnight into
Monday morning, with visibility reductions to a quarter mile or
less for areas within the Central Valley.

...Midweek...

An upper level wave moves out of the eastern Pacific Monday night
and into Tuesday increasing precipitation chances and breezy
conditions to the region. Precipitation begins late Monday night
and into early Tuesday morning for the Coastal Range and Shasta
county area. Later, precip spreads east and south, but remains
along and north of the I-80 area for Tuesday. Coverage will be
isolated for the showers for much of Tuesday. By the afternoon,
instability and moisture increase giving way to thunderstorm
chances (10-25 percent) for areas north of I-80. Best chances
will be within the Sierra, Sacramento Valley, and Coastal Range.
By Wednesday, coverage will be scattered to widespread across the
entire forecast area for precipitation, with snow levels above
8000 feet. Thunderstorm chances will be 10-25 percent. A brief
lull in precipitation Thursday morning and afternoon, before
another round of precipitation moves into the region bringing
breezier conditions.

...Friday Onward...

An active pattern continues for CA Friday and into next weekend,
with another upper level wave moving out of the eastern Pacific.
This system has trended cooler over the past couple of runs of the
NBM. Snow levels are looking to be above 7500 feet by Friday
afternoon and evening and remaining so through the weekend.
Chances for widespread precipitation with the system as it moves
through. Along with the precipitation, conditions will be breezy
for the forecast area. Confidence remains low on the full
development, track, and snow levels with the system.

&&

.AVIATION...

Persistent low ceilings and reductions to visibility across the
Valley and lower foothills through the TAF period. RDD and RBL
have started to see some clearing, but this is expected to be
brief before stratus redevelops this evening creating lower
ceilings and visibility reductions. LIFR to IFR conditions are
expected overnight and into Monday morning, with light and
variable winds. Quarter mile or less visibilities for areas in the
Sacramento Valley. Areas in SCK and MOD will see visibility
reductions but down to half mile or less.

&&

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

$$