Alta Sierra, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

549
FXUS66 KSTO 022216
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
216 PM PST Mon Feb 2 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 morning fog in the Valley through the
   week.

 - Pattern change late weekend and into early next week, with
   potential for precipitation.

&&

.DISCUSSION...

...Today through Friday...

Skies are partly to mostly sunny across the area, with a few hazy
spots. Temperatures have warmed into the 70s in the northern
Sacramento Valley and 60s elsewhere in the Valley. Areas in the
mountains are in the 40s to 50s. Ridge of high pressure will
remain in place through the week, with light and variable winds
and morning fog. HREF continues to show fog each morning through
Friday for areas in the southern Sacramento Valley towards the
northern San Joaquin Valley. Around the Sacramento area fog will
be patchy, with visibility reductions to a half mile, while areas
in the northern San Joaquin Valley sees reductions to a quarter
mile or less. This will be a rinse and repeat situation through
Friday. Thus, we have issued another Dense Fog Advisory from 6z
through 18z for the northern San Joaquin Valley for tonight into
tomorrow morning.

Besides the fog, conditions will remain dry with low RH values in
the teens to 20s for the mountains each afternoon through Friday.
Temperatures will continue to be above normal this week, with a
slight cooling trend over the weekend.

...Saturday and onward...

Dry conditions and seasonal temperatures on Saturday, with a
change in the ridging over the southwestern United States come
Sunday. Ensembles have started to pick up on a pattern change
taking shape end of the weekend and into early next week that
would break down the ridge and introduce precipitation chances. At
this time, ECMWF and GFS ensembles have hinted at the possibility
of widespread precipitation for the region, with a continued
active pattern through all of next week. Probabilities at this
time for over a quarter of an inch of precipitation are 30-40
percent for the Valley, and over 60 percent for the foothills,
mountains, and Shasta county area. Confidence is low at this time
on rain/snow amounts, timing, and breakdown of the ridge.

&&

.AVIATION...

VFR conditions expected through the evening, with conditions
turning IFR to MVFR as visibilities drop. Patchy dense fog around
05-06z for SAC, SMF, MHR, and MCC through 15-16z. Visibility
reductions down a half mile at times for those locations. Areas in
the northern San Joaquin area will see more widespread dense fog,
with visibilities of a quarter mile or less. RDD and RBL will
remain VFR through the TAF period.

&&

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

&&

$$