310
FXUS66 KSTO 272026
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
126 PM PDT Sun Jul 27 2025

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

.DISCUSSION...

.SYNOPSIS...
Chances for afternoon and evening mountain thunderstorms this
week, with the highest chances today and around mid-week.
Otherwise, near to below- normal temperatures expected into next
week breezy onshore winds at times.

&&

.KEY MESSAGES...

* Today:
 - Chances (15-30%) for isolated to scattered mountain showers and
   thunderstorms this afternoon and evening. Highest potential
   over the Southern Cascades / Sierra crest and Coastal Range,
   mainly from Plumas County northward.
 - Main storm hazards include lightning, brief heavy rain, gusty
   winds, small hail, and possible fire starts.
 - Elevated fire weather conditions are expected in the mountains
   into the due to the lightning threat and any strikes outside
   the main precipitation core will pose the threat for fire
   starts.
 - Afternoon highs in the 80s and low 90s throughout the Valley as
   below normal highs continue.

* Monday-Thursday:
 - Mountain thunderstorm potential will generally remain outside
   of the area early this week, but isolated thunderstorms could
   develop over the Coast Range Monday afternoon and evening.
 - Mountain thunderstorm chances (10-25%) expected during the
   afternoon and evening hours this week, with storm coverage
   increasing by mid-week as a trough moves through the region.
 - Slight warming trend through early this week, but highs will
   remain below normal. Expect Valley highs in the 90s Monday and
   Tuesday.
 - Periodically breezy onshore flow expected during the afternoons
   and evenings.

.Changes from previous forecast...
 - Minimal changes from the previous forecast.

&&

.AVIATION...

Mostly VFR conditions expected over the next 24 hours across
Interior NorCal. Isolated to scattered mountain thunderstorms may
cause MVFR/IFR conditions through 03z Monday. Isolated
showers/thunderstorms possible in the northern Sacramento Valley
from 21Z Sunday to 01Z Monday. For the Valley, winds generally
less than 12 kts with gusts up to 15 kts between 22Z Sunday and
03Z Monday. For the Delta vicinity, sustained winds 10 to 20 kts
with gusts 20 to 25 kts at times through 12Z Monday. Potential for
MVFR ceilings from 12Z to 16Z Monday in the Delta.

&&

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

$$