866
FXUS66 KSTO 042112
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
112 PM PST Wed Feb 4 2026

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

.KEY MESSAGES...

 - Dry weather with patchy fog in the Valley and lower foothills
   expected through the week

 - Confidence increasing in a pattern change late weekend into
   next week bringing renewed chances for precipitation
 &&

.DISCUSSION...

...Today through Saturday...
Current GOES-West visible satellite imagery shows the fog and
stratus from Valley this morning has lifted and burned off, with
abundant sunshine being observed. Another round of dense fog will
be possible again tonight into Thursday morning with, high
resolution guidance indicating a 50 to 70 percent chance mainly
south of Sacramento. Another Dense Fog Advisory has been issued to
address the threat for dense fog in the northern San Joaquin
Valley from 10 PM tonight through noon Thursday. Patchy fog may
develop in other Valley locations as well.

The upper level pattern will feature strong high pressure over
much of the western US today, gradually weakening and shifting
eastward later in the week. Above normal temperatures will prevail
across interior NorCal, with highs in the 60s to 70s in the
Valley and foothills, and 50s to 70s in the mountains. Additional
fog development will be possible each morning through Saturday in
the Valley. A weak trough may bring the potential for light
showers over the mountains south of Highway 50 on Friday but
little to no accumulations are expected.

...Sunday and onward...
Confidence is increasing in a pattern change later this weekend
into next week. As the upper level ridge breaks down and shifts
eastward, ensemble guidance and cluster analysis indicate that upper
level troughing develops, bringing along the potential for
showers, mountain snow, breezy winds and cooler temperatures
Sunday through the middle of next week. The Climate Prediction
Center 8 to 14 day outlook then favors below normal temperatures
and above normal precipitation for the February 12th through 18th
timeframe, indicating the potential for active weather to continue
through the middle of February.

&&

.AVIATION...
Improving conditions for sites within the Sacramento Valley by
this afternoon and evening with sites at VFR conditions after 00z
Thu, outside of MOD and SCK who will remain IFR to MVFR due to fog
and low stratus. Overnight, we expect visibilities to drop to IFR
to LIFR conditions after 06z from the southern Sacramento Valley
southward as low as quarter-mile with accompanying low clouds.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory from 10 PM this evening to noon PST Thursday
for Northern San Joaquin Valley.

&&

$$