355
FXUS66 KSTO 151914
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1214 PM PDT Mon Jun 15 2026

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

.KEY MESSAGES...

 - Hot, well-above average temperatures through Tuesday with
   widespread Moderate HeatRisk and areas of Major HeatRisk in the
   northern/central Sac Valley. Hottest temperatures today.

 - Chances for mountain showers/thunderstorms along the Sierra
   crest on Thursday into Friday.

 - Cooler temperatures Thursday into the weekend with increased
   Delta breeze.

&&

.DISCUSSION...

Hot, well-above normal temperatures continue today with
widespread Moderate HeatRisk and areas of Major HeatRisk in the
northern/central Sacramento Valley and adjacent foothills. Hottest
temperatures of the week are expected today, with highs
approaching 110 in the northern Sacramento Valley. Expect elevated
low temperatures tonight as well, which will limit overnight
relief. As a result, an Extreme Heat Warning remains in effect
through 11 PM Tuesday. Diurnal Delta Breeze influence will work
to keep the vicinity Delta and Sacramento area cooler compared to
the rest of the Valley through this heat event, but highs will
still be in the mid to upper 90s. Remember to stay cool and
hydrated, and consider checking in on those more sensitive to
heat.

The hot temperatures combined with low relative humidity and
breezy onshore winds, will continue the pattern of elevated fire
weather conditions in the northern Sacramento Valley and adjacent
terrain through Tuesday. Daytime humidities will be in the teens
to mid 20s, with overnight recoveries in the 50s, though both
daytime and overnight relative humidities should gradually
improve into the weekend.

On Wednesday, a gradual cooling trend begins as upper level
ridging begins to break down. Near to below normal high
temperatures are expected through the weekend. While we`re not
expecting widespread precipitation with this pattern change, there
is an increasing chance (15-25%) for isolated showers and
thunderstorms along the Sierra crest on Thursday and into Friday.

&&

.AVIATION...

VFR conditions with clear skies over the next 24 hours. In the
vicinity Delta, Westerly gusts up to 25-30 kts are possible
through 18Z Tuesday. In the southern Sacramento Valley, west to
southwest gusts 15 to 20 kts are possible between 00Z-05Z Tuesday.
Sustained winds 12 kts or less elsewhere.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 11 PM PDT Tuesday for Butte County
Below 1000 ft-N. Sac Valley in Tehama County-Shasta County
Foothills 1000-3000 ft-Shasta Lake Area & 1-5 1000-3000 ft-
Shasta Metro-Sierra (Tehama-Plumas) 1000-3000 ft-Tehama Co Coast
Range Above 3000 ft-W Tehama Co Foothills 1000-3000 ft-W. Shasta
County 1000-3000 ft-W. Shasta County Above 3000 ft.

&&

$$