Marine Weather and Tide Forecast for Walnut Grove, CA

FXUS66 KSTO 132007 AFDSTO

Area Forecast Discussion National Weather Service Sacramento CA 107 PM PDT Mon Oct 13 2025

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

SYNOPSIS
A wet, cold system will continue to bring widespread rainfall and the season's first measurable snowfall to the mountains through early Wednesday morning. Latest precipitation and snowfall amounts have trended down.

KEY MESSAGES

* TODAY - WEDNESDAY AM:

- Precipitation coverage and intensity is expected to increase later this afternoon as a cold, wet system continues to move across the area.

- A Winter Storm Warning is in effect until 5 AM Wednesday for the Sierra Nevada and Lassen NP areas above 6500 feet. Total snowfall accumulations of 4-8" are expected along the I-80 and Highway 50 corridors, as well as Lassen National Park. 1-2 feet of snow are anticipated south of Highway 50, with the heaviest late tonight and Tuesday.

- Widespread Valley and foothill rain is expected today, with the heaviest rainfall anticipated later this afternoon into the overnight hours. Latest WPC guidance indicates rainfall totals of 0.50" to around 1.50" in the Valley and Sierra foothills.
Highest precipitation totals generally along and south of I-80.

- Scattered showers are expected on Tuesday, with the potential for isolated thunderstorms (10-15% chance). Best thunderstorm potential will be over the northern San Joaquin Valley and adjacent foothills.

- Lingering showers through early Wednesday morning, followed by drier conditions.

* WEDNESDAY PM - SATURDAY:

- Dry conditions expected with a gradual warming trend and periodically breezy winds. Below to near normal temperatures are anticipated, with Valley highs in the 70s.

- Trough moving through in northwest flow may bring light mountain showers on Sunday, but confidence is low.

AVIATION

A weather system will continue to impact interior NorCal through Tuesday, bringing MVFR/IFR/LIFR conditions from rain and mountain snow. Isolated thunderstorms possible through Tuesday. Snow levels 5500-6500 feet. Gusty southerly winds expected through 06z Tuesday, with gusts up to 15-25 kts in the Valley and Delta and up to 20-30 kts over the mountains. Gusty and erratic winds near thunderstorms.
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