Vacaville California Weather Forecast Discussion

056
FXUS66 KSTO 092024
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
124 PM PDT Thu Oct 9 2025
For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.
.SYNOPSIS...
A weak system brings scattered showers and thunderstorms today
through Saturday north of I-80. A colder, wet system will then
bring widespread rainfall and the season`s first measurable
snowfall to the mountains, though exact amounts and timing are
still uncertain.
.KEY MESSAGES...
* TODAY - SUNDAY:
- A weak system begins to bring breezy winds and scattered
   showers today, with precip primarily in Shasta County and the
   southern Cascades. Potential for rain continues through
   Saturday afternoon with a 55 to 80% chance of 0.25 inches in
   the aforementioned areas over the 72 hour period.
- 10-15% chance for thunderstorms this afternoon/evening in
   Shasta County, and again on Saturday afternoon/evening.
- Briefly drier conditions on Sunday before the next system
   arrives early next week.
* MONDAY - WEDNESDAY:
- A colder, wet system arrives early next week, bringing
   widespread rainfall and the season`s first measurable mountain
   snowfall through Wednesday.
- Exact timing and amounts are still uncertain for this system,
   but there`s currently a 50-60% chance for an inch of rain
   everywhere below 5500 ft, and a 30-50% chance for 6 inches of
   snow or more in the Sierra above 5500 ft.
- 10-20% chance of thunderstorms Monday evening into Tuesday
   morning as well, as the system begins to move onshore.
.AVIATION...
General VFR conditions forecasted outside of scattered MVFR/IFR
conditions in the Sacramento Valley and northern San Joaquin
Valley from 09Z to 17Z Friday. A weak system will bring scattered
light rain and a 15-20% chance of isolated thunderstorms to Shasta
County after 06Z Friday. South winds 10-15 kts with gusts 15 to
20 kts through the Delta and northern/central Sacramento Valley
until 03Z Friday. South gusts up to 25 kts over the mountains
through 18Z Friday.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS STO Office Area Forecast Discussion