261
FXUS66 KSTO 122200
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
300 PM PDT Sun Oct 12 2025

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

.SYNOPSIS...
Dry weather with breezy north to west winds ahead of a wet, cold
system bringing widespread rainfall and the season`s first
measurable snowfall to the mountains Monday and Tuesday.

.KEY MESSAGES...

* TODAY:

 - Dry conditions with breezy north to west winds up to 15-20 MPH,
   shifting to west across the Delta and south of I-80 late this
   afternoon and evening.

* MONDAY - WEDNESDAY:

 - A colder, wet system arrives early next week, bringing
   widespread rainfall and the season`s first measurable mountain
   snowfall through Wednesday evening.

 - Winter Storm Warnings are in effect from 5 AM Monday to 5 AM
   Wednesday for the Sierra Nevada and Lassen NP areas above 6500
   feet for 1-2 feet of snow, up to 3 along the highest peaks and
   gusts up to 30-35 MPH. Heaviest snow accumulation will be
   Monday afternoon and evening with highest totals south of Hwy.
   50.

 - Rain for the Valley/foothills is expected to begin Monday
   morning with heaviest rainfall rate later in afternoon and
   evening before transitioning to lighter, scattered showers on
   Tuesday. Valley amounts are forecasted around 0.75-1.25" in the
   Valley with higher amounts along the Motherlode and eastern
   portions of the Valley.

 - 10-20% chance of thunderstorms Monday evening into Tuesday
   morning as well, as the system begins to move onshore.

 - Dry conditions develop after Wednesday with breezy north winds.

.AVIATION...

Decreasing north to west winds across the northern and central
Sacramento Valley with breezy south to east winds developing
after 21z Sun across the Delta and southern Sac. Valley into 18z
Mon with gusts up to 15-20 kts. Scattered showers begin over the
northern Sac Vally and Coastal Range around 10z Mon ahead of
MVFR/IFR conditions from rain around 18z Monday into Tuesday
moving into the Valley and later mountain snow over the Sierra.
Snow levels will be 5500 to 6500 feet on Monday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 5 AM Monday to 5 AM PDT Wednesday for
West Slope Northern Sierra Nevada-Western Plumas County/Lassen
Park.

&&

$$