380
FXUS66 KSTO 021936
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1236 PM PDT Sat Aug 2 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 5-15% across the Coast Range and
   Shasta County mountains in the afternoon/evening. Highest
   chances Sunday. Latest trends have brought t-storms chances
   down.
 - 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...
 - T-storm chances for today (Saturday) in the Shasta County
   mountains and Coastal Range have trended down. Slight decrease
   in t-storm chances tomorrow afternoon-evening (Sunday), as
   shortwave trough is trending weaker for our area.

&&

.AVIATION...

Generally VFR conditions expected to prevail next 24 hours across
interior NorCal. MVFR/IFR possible due to a slight (5-10%) chance
for isolated mountain showers/thunderstorms across Shasta County
mountains today until around 04Z Sunday. Otherwise, breezy onshore
surface winds up to 12 kts expected through Valley and Delta.
Gusts 20-25 kts in Delta and vicinity area through 18Z Sunday.

&&

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

$$