617
FXUS66 KSTO 312029
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
129 PM PDT Mon Aug 31 2026

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



.KEY MESSAGES...

  - Well below normal temperatures persist through much of the
    week.

  - Elevated Fire Weather conditions continue into this evening
    in the northern Sac Valley, northeastern foothills, and Burney
    Basin due to low humidity and breezy winds.

  - Increasing confidence in areas of unsettled weather mainly
    Thursday and Friday, potentially into the weekend.

  - Potential for tropical system remnant moisture next week, but
    confidence remains low at this point.

&&

.DISCUSSION...

Today through Early This Week...

Dry weather with cooler temperatures today as a low pressure
system moves through, with Valley highs generally in the 80s and
then dropping into the 70s to low 80s by Tuesday. Breezy onshore
winds have developed, south to southwest winds, already gusting to
around 20 to 30 mph, strongest near the Delta and in the northern
and central Sacramento Valley, adjacent foothills, and the Burney
Basin. Humidity levels are dropping into the 20s% and are
expected to drop as low as the teens this afternoon and evening for
the northern Sacramento Valley, northeast foothills, and Burney
Basin. The gusty winds and low humidity will lead to periods of
elevated fire weather conditions for those areas. Tuesday, as the
bulk of the trough approaches, there is a slightly increased
potential for isolated showers and thunderstorms in the
northwestern portion of Shasta County, as suggested by recent CAMS
runs and a probability of thunderstorms of 15%, so they have been
added to the forecast.

Mid to Late Week...

The remainder of the week and into the weekend, troughing will
remain the dominant pattern and will help maintain cooler than
normal temperatures. Confidence is increasing in the potential
for precipitation, especially north of I-80, including in the
Valley. The latest storm totals have trended higher, ranging up
to near an inch over northern Shasta. Totals up to a couple
tenths of an inch are forecast in the Sacramento Valley. There is
also a 20-25% probability of thunderstorms Thursday in the
mountains north of I-80. Upper low spinning centered over Oregon
may have some disturbances bringing some showers into the weekend.

There is the potential for a tropical system to bring moisture
into California early next week, but ensembles are showing many
different tracks, so confidence in precipitation from this into
Northern California remains fairly low.
&&

.AVIATION...

VFR conditions prevail over the next 24 hours across interior
NorCal. Surface south to west winds incresing to 10 to 15 kts in
the afternoon with gusts up to 20 to 30 kts, highest in the Delta
and northeast foothills. The Delta will see contiuned gusts
through 18 z Tuesday but elsewhere winds decrease after 03z with
lingering 15 to 25 kt gusts until 09z Tuesday for the northeast
foothills. Periods of haze and smoke exepcted across the forecast
area through 18z Tuesday.
&&

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

$$