047
FXUS66 KSTO 011934
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1234 PM PDT Fri Aug 1 2025

.DISCUSSION...

.SYNOPSIS...
Chances for afternoon and evening thunderstorms continue through
the weekend primarily across the Coast Range and Shasta County
mountains. Near to slightly below normal temperatures are expected
into the weekend and early next week as periodically breezy
onshore winds continue. A warming and drying trend is then
anticipated from mid week onward with areas of Moderate HeatRisk
returning by late next week.

&&

.KEY MESSAGES...

* Today - Sunday:
 - Thunderstorm chances around 10-25% across the Coast Range and
   Shasta County mountains in the afternoon/evening. Highest
   chances today and Sunday.
 - Main storm hazards include lightning, brief heavy rain, gusty
   winds, small hail, and possible fire starts. Short term model
   trends indicate best thunderstorm chances from 3-8 PM.
 - Elevated fire weather conditions are expected in the mountains
   due to the lightning and gusty outflow wind threat and any
   strikes outside the main precipitation cores will pose the
   threat for fire starts.
 - Afternoon highs in the 90s throughout the Valley as high
   temperatures remain seasonable through the weekend.
 - Periodically breezy onshore flow expected during the afternoons
   and evenings.
 - Probability of south to west wind gusts across the Delta and
   adjacent Valley > 30 mph on Sunday: 60-90%

* Next Week:
 - Slight cool down on Monday as a quick moving system on Sunday
   exits the region.
 - Gradual warming and drying trend expected mid to late week as
   Desert Southwest ridging amplifies.
 - Periodically breezy onshore flow looks to continue as split
   flow aloft persists over interior NorCal.
 - High temperatures trend slightly above normal by the end of the
   week, with 90s to lower triple digits through the Valley,
   Delta, and foothills resulting in areas of Moderate HeatRisk.

.Changes from previous forecast...
 - Slight chances for isolated mountain thunderstorms across the
   Coast Range and Shasta County mountains continues through the
   weekend.
 - Warming trend expected from midweek onward with Moderate
   HeatRisk by late next week.

&&

.AVIATION...
Generally VFR conditions expected to prevail next 24 hours across
interior NorCal. MVFR/IFR possible in isolated mountain
showers/thunderstorms across Shasta County terrain today until
around 04z Sat. Otherwise, breezy onshore surface winds up to 12
kts expected through Valley and Delta, with lighter terrain driven
winds at higher elevations. Gusts 20-25 kts in Delta and vicinity
area from until 09z Saturday, decreasing through the early
morning.

&&

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

&&

$$