


Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
653 FXUS66 KSTO 132107 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 207 PM PDT Sun Jul 13 2025 For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing. .DISCUSSION... .SYNOPSIS... Hot weather continues through Monday with Moderate to locally Major HeatRisk. Increasing Delta breeze influence will bring minor cooling and overnight relief over the weekend and into next week in the Delta and adjacent Valley locations. Dry weather and periodically breezy onshore winds are expected through Friday alongside temperatures returning to near normal mid to late week. && .KEY MESSAGES... * Heat Advisory remains in effect through 11 PM Monday evening for the northern/central Sacramento Valley and surrounding foothills and mountain locations. * Today-Monday: - Broad troughing and attendant northwesterly flow continue as high heights aloft persist. - Widespread Moderate HeatRisk with areas of Major HeatRisk across interior NorCal. - Smoke will continue to impact areas in the vicinity of the Green Fire, with occasional northerly winds spreading smoke and haze southward through the Valley. - Locally breezy northerly flow in the northern/central Sacramento Valley and adjacent terrain, mainly in the overnight through morning timeframe. - Increasing onshore flow and Delta Breeze influence expected through the weekend, bringing minor cooling and overnight relief to the Delta and adjacent Valley. - Low daytime relative humidity with moderate to poor overnight recoveries over foothills and mountains. - Low (5-10%) chance for isolated thunderstorms across the high terrain of Shasta County during the afternoon/evening hours on Monday. * Tuesday-Saturday: - Upper level pattern remains largely persistent with broad troughing/northwesterly flow across interior NorCal. Some signals for ridging and increasing heights aloft into next weekend. - A slight cool down to more seasonable temperatures mid to late week, followed by a gradual warming trend by next weekend. - Periodically breezy onshore flow expected to persist in the afternoon and evening, shifting toward terrain driven influence during the overnight hours. - Strongest onshore winds anticipated on Tuesday as a subtle shortwave ejects through the region. -- Probability of Wind Gusts > 30 mph: 60-90% throughout the Delta and Sacramento Valley. - Persistent and periodic late day wind gusts 20 to 30 mph anticipated throughout the Delta and vicinity each day. .Changes from previous forecast... - Minimal changes from the previous forecast. && .AVIATION... Wildfire smoke will result in MVFR and IFR conditions at times in the northern Sacramento Valley, including KRDD and KRBL. VFR conditions expected elsewhere across interior Northern California over the next 24 hours. West-southwest winds will be breezy through the Delta with gusts 15 to 25 kts through 16Z Monday. Elsewhere, sustained speeds generally at or below 12 knots over the next 24 hours, with periodic gusts 15 to 20 kts in the Valley between 22Z Sunday and 04Z Monday. && .STO WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 11 PM PDT Monday for Burney Basin / Eastern Shasta County-Central Sacramento Valley-Mountains Southwestern Shasta County to Western Colusa County-Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-Shasta Lake Area / Northern Shasta County-Western Plumas County/Lassen Park. && $$