681 FXUS66 KSTO 092053 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 153 PM PDT Wed Jul 9 2025 For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing. .DISCUSSION... .SYNOPSIS... Moderate to Major HeatRisk is anticipated across interior NorCal Thursday through Monday. Some Delta breeze influence will bring minor cooling over the weekend and into next week in the Delta and adjacent Valley locations. Dry and periodically breezy weather continues. && .KEY MESSAGES... * Today: - Seasonable temperatures and dry conditions expected today - Smoke will continue to impact areas in the vicinity of the Green Fire over the next few days - Warming trend begins as trough moves inland and high pressure begins to build * Thursday-Friday: - Upper level ridge continues to build, resulting in dry conditions and warming temperatures with low daytime relative humidity and moderate to poor overnight recoveries - Widespread Moderate HeatRisk with areas of Major HeatRisk across interior NorCal - Locally breezy northerly flow in the northern/central Sacramento Valley and adjacent terrain, mainly in the overnight through morning timeframe * Saturday-Monday: - Continued hot and dry conditions, with widespread Moderate HeatRisk and areas of Major HeatRisk in the forecast for interior NorCal into early next week - There will be some Delta breeze influence over the weekend and into next week that will allow for minor cooling in the Delta vicinity - Upper level ridging looks to continue to be the dominating weather pattern into early next week .Changes from previous forecast... - Temperatures and HeatRisk have trended higher for this weekend through early next week - Issuance of Heat Advisory north of Interstate 80 in the Valley, foothills and mountains from Friday through Sunday && .AVIATION... VFR conditions across interior NorCal next 24 hours. Periods of breezy onshore winds with gusts up to 15 knots in the Delta vicinity through 06z Thursday. Elsewhere, sustained speeds generally less than 12 knots, with gusts up to 15 to 20 knots in the northern Sac Valley after 16z Thursday. Local MVFR conditions possible at times in HZ/FU vicinity of Shasta County wildfire, including KRDD. && .STO WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 11 AM Friday to 11 PM PDT Sunday 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. && $$