Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
314 FXUS66 KSTO 292012 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 112 PM PDT Sun Sep 29 2024 .Synopsis... Above normal temperatures continue through this week, though slightly less hot today with light onshore flow. Temperatures are expected to peak Tuesday and Wednesday, with widespread triple digit highs in the Delta and Valley. Gusty northerly winds and low humidity will bring elevated fire conditions tonight into Tuesday. && .Discussion... A weak trough pattern will bring less hot temperatures for today, with onshore flow bringing some relief, particularly Delta breeze influenced areas. In spite of this, temperatures will still be above normal, 2-8 degrees higher than average. Eastern Pacific ridging will extend eastward, connecting with ridging over the 4-Corners area. This will bring well above normal temperatures on Monday and Moderate HeatRisk across much of the area. Even hotter temperatures arrive Tuesday and Wednesday, with widespread Moderate HeatRisk across the area, and areas of Major HeatRisk in the foothills and adjacent Valley. Temperatures in the Valley are likely to reach triple digits on these days, with the NBM predicting a 30 to 80% probability of temperatures of 100 degrees or greater. Record temperatures are possible, with current forecast record high minimums for Sacramento Executive Airport of 62 and 64 for Stockton Airport Tuesday morning. The record high maximum of 100 for Stockton Airport Tuesday and again on Wednesday could also be tied or broken. The record of 102 for Redding Airport on Wednesday is also vulnerable. In addition to heat, drying north to east winds will develop tonight through Monday. Winds will be gusty with a 20 to 55% probability of gusts 30 mph or greater, primarily along the I-5 corridor in the northern Sacramento Valley. These winds will also cause lower relative humidities during the day (generally 10-20% in the Valley) with poor overnight recoveries (generally 20-50%). These elements combined will lead to elevated fire weather concerns into Tuesday, though primary concerns are for Monday. && .EXTENDED DISCUSSION (Thursday THROUGH Sunday)... Well above normal high temperatures continue Thursday under strong upper level ridging. NBM guidance looks low compared to most ensemble solutions that maintain upper 90s to around 100 in the Central Valley. Gradual cooling Friday into the weekend as upper level ridging slowly weakens. High temperatures remain slightly above normal into Sunday. && .AVIATION... VFR conditions over interior NorCal next 24 hrs. Surface wind below 12 kts except vicinity of the Delta where we can expect southwesterly surface winds up to 20 kts after 00z Mon, as well as in the northern and western Sacramento Valley where northerly gusts up to 20 to 25 kts will occur after 06z Monday. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$