872
FXUS66 KSTO 032140
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
140 PM PST Tue Feb 3 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.
- Pattern change late weekend and into early next week, with
increasing precipitation chances.
&&
.DISCUSSION...
...Today through Friday...
Skies continue to be mostly sunny across the area, with hazy
conditions. Areas in the northern San Joaquin Valley continue to
see low stratus and patchy dense fog this afternoon. Improvements
are expected through the evening hours for the northern San
Joaquin, but it will be short lived as we expect further fog and
low stratus overnight. Temperatures are in the 60s within the
Sacramento Valley and 50s underneath the fog and low stratus.
Areas in the mountains are in the 50s.
HREF continues to highlight dense fog overnight for areas within
the southern Sacramento Valley towards the northern San Joaquin
Valley, but highest chances remain around Stockton and Modesto.
Thus, a Dense Fog Advisory was issued for the northern San Joaquin
area from 10pm this evening through 10am tomorrow for quarter mile
visibilities or less. Improvements to the low stratus on Thursday
and Friday as probabilities for a half mile or less have gone
down. Temperatures have also increased, with the mid 60s to lower
70s across the area. Warmest temps in the foothills and in the
northern Sacramento Valley. Minimum RH values Thursday and Friday
will be in the teens for areas within the foothills and mountains,
with light and variable winds.
...Saturday and onward...
Dry conditions and seasonal temperatures on Saturday as the ridge
aloft starts to breakdown and shift eastward. By the end of the
weekend and into early next week we transition to more troughing
across the southwestern United States increasing our chances for
an active weather pattern. Long range guidance from the ECMWF and
GFS indicate an active week ahead, with potential for multiple
systems moving through the southwestern United States. The first
being end of the weekend and into early next week, with a
secondary system end of next week and into the following weekend.
Probabilities for the first storm have gone up in QPF with 80
percent chance for a quarter of an inch or greater in the
foothills and mountains, while in the Valley probabilities have
decreased toward 20 percent. Snowfall over 6 inches is sitting
around 40-50 percent for the mountains.
Confidence continues to remain low at this time on rain/snow
amounts, timing, and breakdown of the ridge. As the pattern change
develops and we move through the week we will have a better
understanding of impacts.
&&
.AVIATION...
VFR conditions prevail for sites within the Sacramento Valley
this afternoon and evening, while MOD and SCK remain IFR to MVFR
due to fog and low stratus. Skies will be mostly sunny for the
Sacramento Valley, with light and variable winds. Improvements to
visibility in SCK and MOD through the afternoon, but overnight we
expected visibilities to drop once again to IFR through the end
of the TAF period. Areas around SAC, SMF, MCC, and MHR will see
visibility reductions down to a half mile around 10z through 16z.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory from 10 PM this evening to 10 AM PST
Wednesday for Northern San Joaquin Valley.
&&
$$
