Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
838 FXUS66 KSTO 160847 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 147 AM PDT Fri Aug 16 2024 .SYNOPSIS... Near normal to slightly below normal temperatures over the next week. Saturday will be breezy with a slight chance of isolated showers north of Redding in higher terrain. && .Discussion... There`s a fairly clear gradient between current temperatures in the northern Sacramento area and areas south of the downtown area, as the Delta breeze kicks into gear, with a five degree difference currently between Sacramento Executive AP and Sacramento Intl AP. Lows tonight in the Valley are expected to reach the low to mid 60s, so areas away from the Delta still have a ways to go. Today, an upper trough begins to build off the coast of Oregon, very demure, very mindful. This will maintain the normal temperatures we`ve been experiencing. The real cool-down occurs Saturday as the trough continues to deepen without shifting eastward much at all. The NBM currently is showing a 65 to 95% probability of temperatures below 90 degrees in the Valley, and up to a 30% chance of temperatures below 85 degrees. The onshore flow causing the overall cool-down will also bring periods of gusty winds throughout Saturday and into Sunday. While this would normally be a larger fire weather concern and attention will still need to be paid to areas with ongoing fires, day-time relative humidities will see an increase with this pattern as well, keeping us below warning criteria. Finally, on Saturday afternoon and evening, there is a 10 to 20% probability of isolated thunderstorms in northeastern Shasta and far eastern Tehama counties. Sunday and Monday see a slight uptick in temperatures, though they`ll still be below normal for the time of year. Otherwise, winds will calm by Sunday and more or less calm and dry weather is expected afterwards. && .EXTENDED DISCUSSION (Tuesday THROUGH Friday)... That aforementioned trough is going to try to hang around a bit longer next week as well. Ensembles and clusters show fairly good agreement on the trough being pushed out west by a ridge building over the Four Corners area, and weakening slightly before digging back down and deepening again off the coast of California and Oregon. This effectively means we`ll temporarily see temperatures rise to around normal again early next week (low to mid 90s in the Valley), before dipping back down to below normal by mid to late week. Probabilities of temperatures below 90 degrees in the Valley increase from 30 to 40% on Wednesday to 60 to 80% by Friday. && .AVIATION... VFR conditions prevail next 24 hours. Surface wind gusts generally less than 12 kts, except vicinity west Delta occasional gusts 15-25 kts mainly after 06Z Saturday. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$