Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
661 FXUS66 KSTO 151955 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1255 PM PDT Fri Aug 15 2025 .DISCUSSION... .SYNOPSIS... Warmer weather today, then near to below normal temperatures through the weekend and into next week with mainly Minor HeatRisk and periodically breezy onshore flow. Slight chance of thunderstorms mainly over Shasta County vicinity this weekend, otherwise dry conditions prevail. && .KEY MESSAGES... *Today: - Slightly warmer today with dry conditions - Afternoon highs the 90s to near 100 for much of the Valley and foothills - Widespread Minor HeatRisk with localized Moderate HeatRisk *Weekend: - Cool down with near to below average temperatures over the weekend with Minor HeatRisk and rising relative humidity - Periodically breezy onshore flow is forecast at times, strongest in the Delta vicinity and over the Sierra Crest - 15-35% chance of mostly wet thunderstorms in Shasta County (includes northern Sacramento Valley), northern Coastal Range, and southern Cascades, dry weather elsewhere - Potential for nocturnal convection Saturday night into Sunday morning as well mainly in Shasta County *Next Week: - Below normal temperatures on Monday will gradually warm back up to near normal through next week as high pressure is favored to build back in over the Western US, centered over the Four Corners region - Widespread Moderate HeatRisk returns to the forecast late next week as a result of the warming trend - Drying trend will bring lower relative humidity to the area mid to late next week, around 15-20% in the afternoons .Changes from previous forecast... - Added mention of the potential for nocturnal convection Saturday night into Sunday morning over Shasta County vicinity && .AVIATION... VFR conditions will continue for the next 24 hours across interior NorCal. Sustained surface winds generally at or below 12 kts except in the Delta with west-southwest surface winds 12-15 kts with gusts 20-25 kts 23Z Friday - 15Z Saturday. Northerly surface wind gusts of up to 15-20 kts in the northern Sacramento Valley through 03Z Saturday. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$