533
FXUS66 KSTO 021916
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1216 PM PDT Fri Oct 2 2026

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



.KEY MESSAGES...

   - Heat Advisory in effect from 11 AM Saturday - 10 PM
     Wednesday the Sacramento Valley, Delta, northern San Joaquin
     Valley, and adjacent foothills.

   - High temperatures, 10-20 degrees above normal, will lead to
     widespread Moderate HeatRisk in the Delta, Valley, and
     foothills Today-Thursday, with areas of Major HeatRisk in
     the Delta.

&&

.DISCUSSION...

...Today (10/02)...

High pressure aloft will be the headline for at least the next 7
days, with continued dry and hot conditions expected. For today,
highs will reach the low to mid 90s across most of the Valley with
upper 70s to upper 80s for the higher elevations. A weak surge of
monsoonal moisture will move through portions of the area today,
along with weak offshore troughing, have facilitated the
development of scattered high clouds. Resulting cloud cover will
help mitigate some of the unseasonably hot temperatures today.
Widespread Moderate HeatRisk is expected trough the Delta and
foothills, with areas in the Sacramento and northern San Joaquin
valleys.


...Saturday-Wednesday (10/03-10/07)...
Latest model runs keep high pressure firmly in control of the
weather pattern as we move into the weekend and mid next week.
High temperatures will continue to climb well-above normal (10-20
degrees) for a significant portion of the Valley, Delta, and
adjacent foothills/thermal belts. Weak offshore flow on Saturday
and Sunday will lead to isolated areas of Major HeatRisk in the
Delta and surrounding terrain, with Moderate HeatRisk for the rest
of the region. Unseasonably hot temperatures, combined with
limited Delta Breeze/overnight cooling, and potential societal
impacts, a Heat Advisory is in effect from 11 AM Saturday morning
until 10 PM Wednesday for the Valley, Delta, and adjacent
foothills. Several large-scale activities, along with local Fall
events take place this weekend, so if you are outside remember to
drink plenty of water/stay hydrated, find shade and take breaks,
and check on those most sensitive to heat illness!

...Thursday and beyond...
Extended guidance keeps us under broad ridging through the end of
next week, with some slight uncertainty if mid to upper 90s will
continue into next weekend. Cluster analysis reveals overall
agreement in at least upper level ridging remaining in the region,
however the strength and a slight shift to zonal heights aloft
appear in some cluster members. Regardless, we expect at least
slightly above normal to above normal high temperatures to
continue through at least Thursday of next week.

&&


.AVIATION...


VFR conditions continue through the TAF period for Interior
Northern California. Light and variable winds through the period,
with a few gusts to 15 kts within the Delta this evening.
Otherwise, we will see a SCT to BKN cloud deck shift through the
region through the TAF period.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM Saturday to 10 PM PDT Wednesday 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-Shasta County Foothills 1000-3000 ft-Shasta Metro-Sierra
(Tehama-Plumas) 1000-3000 ft-Southern Motherlode 1000-3000 ft-
Sutter/Yuba counties below 1000 ft-Tracy Triangle Below 1000 ft-
W Tehama Co Foothills 1000-3000 ft-W. Glenn/Colusa Foothills
1000-3000 ft-W. Shasta County 1000-3000 ft-W. Stanislaus County
Above 1000 ft & I-5-W. Yolo County including Capay/I-505-Yolo /
Solano County Hills.

&&

$$