609 FXUS66 KSTO 151954 AFDSTOArea Forecast Discussion National Weather Service Sacramento CA 1254 PM PDT Mon Sep 15 2025
For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing.
.DISCUSSION...
.SYNOPSIS... Dry weather with above normal temperatures in the 90s through Wednesday. Clouds and a few showers and isolated thunderstorms moves in Thursday into the weekend to bring cooling trend. &&
.KEY MESSAGES... * TUESDAY - WEDNESDAY: - Ridging aloft brings dry conditinos and above normal temperatrures and areas of moderate heat risk.
* THURSDAY - SATURDAY:
- Moisture from tropical system Mario will move into area bring clouds and chance of moisture to all areas. No strong forcing with the moisture so likely most activity in higher terrain but enought moisture for light showers or even a thunderstorm in the valley. Main time period looks to be Thursday night through Saturday.
- Elevated fire concerns will be highest Thursday night into Friday before moisture deepens and humidities increase.
.CHANGES FROM PREVIOUS FORECAST...
- No major changes except to introduce slight chance of thunder to southern valley locations Thursday night.
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.AVIATION... VFR conditions and clear skies expected at interior northern California TAF sites next 24 hours. Surface winds generally less than 12 kts.
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.STO WATCHES/WARNINGS/ADVISORIES... None. &&
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NWS STO Office Area Forecast Discussion