422
FXUS66 KSTO 122051
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
151 PM PDT Fri Jun 12 2026
For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.
.KEY MESSAGES...
-Well above normal temps in the lower elevations, triple digit
highs with widespread Moderate HeatRisk / Areas of Major
HeatRisk into the weekend (outside of Delta breeze influenced
areas).
- The Delta breeze will bring cooling into infuenced areas over
the weekend, with Minor HeatRisk and highs a little less hot, in
the 90s into next week.
-Significant warm-up early next week, Sunday-Tuesday with
Widespread Major HeatRisk for the northern and central
Sacramento Valley. Widespread Moderate HeatRisk elsewhere,
-Hottest temperatures Monday for the area north of I-80, with
areas of Major HeatRisk.
&&
.DISCUSSION...
Temperatures have trended even higher today (1-4 degrees at noon),
and are well above normal. The big change is that winds are
generally much lighter than yesterday, though there are still some
northerly gusts up to 20 mph through the morning for the northern
Sacramento Valley. Humidity levels this afternoon are generally 4
to 8 percent higher, 8 to 10 percent in the Delta, so along with
the lighter winds fire concerns are elevated but generally not
critical. Low humidity levels and periods of breezy onshore winds
will continue into next week. Onshore flow, increasing humidity
and cooling temperatures are expected mid to late week, further
lessening fire weather concerns.
Triple digit Valley highs are expected this afternoon and
continue through at least the early weekend in many locations.
Widespread Moderate HeatRisk is present this afternoon, with
areas of Major HeatRisk, mainly for the northern Sacramento Valley
and adjacent foothills. Delta breeze influenced locations will
see some cooling through the weekend, while the northern
Sacramento Valley, mountains, and foothills are forecast to see
just slightly lower highs. The Heat Advisory continues for the
northern and central Sacramento Valley and adjacent foothills
through 11 pm Saturday, June 13th. While other areas in the
Valley will benefit from the Delta breeze cooling influence,
especially in the evening, it remains important for everyone in
interior NorCal to practice heat safety! Stay cool and hydrated,
and consider checking in on those more sensitive to heat.
Early next week high temperatures have trended even higher for
the northern and central Sacramento Valley, and could see even
higher temperatures than for late this week, up to 110 in some
northern Sacramento Valley locations. Probability of Major
HeatRisk has continued to trend larger there, around 100 percent
in some spots, so confidence is high. An Extreme Heat Warning has
been issued for the northern Sacramento Valley, adjacent
mountains and foothills, and Butte County from 11 am Sunday to 11
pm Tuesday. Temperatures are forecast to trend lower mid to late
week, back to near normal Thursday.
Mainly dry weather is expected into next week. Still can`t
completely rule out a few stray showers or an isolated thunderstorm
over the Sierra crest south of US HWY 50 over the weekend into
Monday.
&&
.AVIATION...
VFR conditions with clear skies over the next 24 hours. Winds
generally less than 12 kts everywhere this afternoon, except in
the vicinity of the Delta, where westerly gusts up to 25 kts
remain until around 12z Saturday.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 11 PM PDT Saturday 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-W Tehama Co Foothills
1000-3000 ft-W. Glenn/Colusa Foothills 1000-3000 ft-W. Shasta
County 1000-3000 ft.
Extreme Heat Warning 11 AM PDT Sunday to 11 PM Tuesday PDT for the
northern Sacramento Valley, surrounding mountains and foothills,
and Butte County.
&&
$$
