985 FXUS66 KSTO 261951 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 1251 PM PDT Sat Jul 26 2025 .DISCUSSION... .SYNOPSIS... Near to below-normal temperatures expected into next week breezy onshore winds at times. Chances for afternoon and evening mountain thunderstorms this weekend. Potential for mountain thunderstorm chances next week, especially by mid-week. A gradual warming trend returns next week. && .KEY MESSAGES... * This Weekend: - Chances (15-30%) for isolated to scattered mountain showers and thunderstorms this afternoon and evening. Highest potential over the southern Cascades, Sierra crest and Coastal Range. - Main storm hazards include lightning, brief heavy rain, gusty winds, small hail, and possible fire starts. - A stray shower or thunderstorm may drift into far western portions of the northern Sacramento Valley this afternoon (10-15% probability) as thunderstorms develop over the Coast Range. - Mountain thunderstorm chances decrease on Sunday to 10-20%. Highest potential over the Coast Range, southern Cascades, and Sierra crest, mainly from Plumas County northward. - Elevated fire weather conditions are expected in the mountains into the weekend due to the lightning threat and any strikes outside the main precipitation core will pose the threat for fire starts. - Afternoon highs in the 80s and low 90s throughout the Valley as below normal highs continue. * Next Week: - Slight warming trend next week, but highs will remain below normal. - Periodically breezy onshore flow expected during the afternoons and evenings next week. - Mountain thunderstorm potential generally less than 10% Monday and Tuesday. - Increased potential for mountain thunderstorms by the middle of next week during the afternoon and evening hours (10-20% probability Wednesday-Thursday). .Changes from previous forecast... - Minimal changes from the previous forecast. && .AVIATION... Mostly VFR conditions expected over the next 24 hours across Interior NorCal. Isolated to scattered mountain thunderstorms may cause MVFR/IFR conditions until around 03z-06z Sunday. Isolated thunderstorms possible in the northern Sacramento Valley through 03Z Sunday. For the Valley, south to southwest surface winds generally less than 12 kts with gusts up to 15 to 20 kts between 22Z Saturday and 06Z Sunday. For the Delta vicinity, sustained winds 10 to 20 kts with gusts 20 to 25 kts at times. Potential for MVFR ceilings from 12Z to 16Z Sunday in the Delta and adjacent Valley locations. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$