807
FXUS66 KSTO 101930
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1230 PM PDT Thu Sep 10 2026

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

.KEY MESSAGES...

  - Hot, dry and breezy through Thursday, with areas of Moderate
    HeatRisk and elevated fire weather conditions

  - Notable cool down over the weekend, with near to below normal
    temperatures expected

  - Breezy onshore winds Thursday-Saturday followed by gustier
    north winds Saturday night-Monday with elevated to critical
    fire weather conditions over the weekend

&&

.DISCUSSION...

Today-Friday:

Mid to high level clouds are once again passing through portions
of interior NorCal on GOES-West visible satellite imagery this
afternoon. Highs are expected to be very warm today, with
widespread triple digits and Moderate HeatRisk (areas of Major
HeatRisk) forecasted in the Valley. To this point, a Heat
Advisory remains in effect through 10 PM PDT tonight. Elevated
fire weather conditions remain today as well, with breezy north
winds at times and low daytime relative humidity. Virga and
sprinkles remain possible (10-15% chance) over the Sierra this
afternoon, along with a non-zero chance for isolated lightning.
Highest chances for both are south of I-80.

On Friday, onshore flow returns, along with the beginning of a
notable cool down as the ridging overhead begins to flatten and
troughing progresses inland over the Pacific Northwest. Breezy
southerly winds are expected along with the closer to normal
temperatures on Friday, strongest gusts will occur in and near the
Delta, as well as over the Sierra crest.


Weekend into Mid-Next Week:

Saturday morning and afternoon, as the troughing moves further
inland, gusty south to west winds are expected across interior
NorCal. The NBM has gusts around 25 to 35 mph on Saturday. In the
evening and transitioning into Sunday, winds will remain gusty
but the direction will shift to north to east. NBM probabilities
for 30 mph gusts or higher on Sunday and Monday have trended down
slightly (20 to 40% for both days now), however chances for gusts
of 25 mph or higher remain good (around 50 to 70% in the
Sacramento Valley along and west of I-5). Due to these windy
conditions, along with generally low relative humidities, a Fire
Weather Watch has been issued for portions of the Sacramento
Valley and northern foothills from 11 am PDT on Saturday, to 11 am
PDT on Monday. Areas not included in the Watch will still see
elevated fire weather conditions, just more limited in time and
scope.

Temperatures over the weekend will be near to below normal with
highs in the Valley and foothills fluctuating in the 80s through
Monday. Tuesday and onward, weak troughing will remain over
NorCal, maintaining near normal temperatures and periodically
breezy winds. Be sure to follow the forecast at weather.gov for
any updates!

&&

.AVIATION...

VFR conditions prevail at TAF sites across the forecast period.
Winds in most areas will remain at 12 kts or less for the forecast
period, except in the Delta and nearby Valley locations. Winds in
the Delta will gust 20 to 25 kts starting at 21z today, northern
San Joaquin Valley and Sacramento sites seeing occasional gusts
up to 15 kts after 22z.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Saturday morning through Monday morning
for Butte County Below 1000 ft-Central Colusa County Incl. I-5-
Central Glenn Co & Interstate 5-Eastern Colusa County-Eastern
Glenn County-N. Sac Valley in Tehama County-Shasta Metro-Sierra
(Tehama-Plumas) 1000-3000 ft-Sutter/Yuba counties below 1000 ft.

Heat Advisory until 10 PM PDT this evening for Butte County
Below 1000 ft-C. San Joaquin County including Stockton-C. Solano
County including Fairfield-C. Stanislaus County including
Modesto-C. Yolo/NE Solano including Woodland-Central Colusa
County Incl. I-5-Central Glenn Co & Interstate 5-Central
Motherlode 1000-3000 ft-E. Diablo Range Above 1000 ft-Eastern
Colusa County-Eastern Glenn County-N. Motherlode 1000-3000 ft-N.
Sac Valley in Tehama County-NE San Joaquin Valley Below 1000 ft-
SW Solano County including Vallejo-Sac Metro/W. El Dorado/Amador
County-Sacramento County Delta-San Joaquin County Delta-Sierra
(Tehama-Plumas) 1000-3000 ft-Southern Motherlode 1000-3000 ft-
Sutter/Yuba counties below 1000 ft-Tracy Triangle Below 1000 ft-
W. Stanislaus County Above 1000 ft & I-5-W. Yolo County
including Capay/I-505-Yolo / Solano County Hills.

&&

$$