, Issued at 1250 PM PDT Mon Aug 31 2026 (Monday through Friday)
Upper-level shortwave troughing will swing into Northern California tomorrow; this will result in temperatures well below normal, a chance for drizzle/light rain, and widespread cloud cover. The best chances for drizzle/light rain will be in the North Bay, particularly along the coast and in the higher terrain with the help of orographic lift. A reinforcing upper-level low and an attendant cold front will approach the area Wednesday into Thursday. This will keep well below normal temperatures and cloudy conditions around and likely make the marine layer arbitrary. There will be a better chance for drizzle/light rain with this round with a lifting mechanism in place as PWAT climbs to near one inch (90th percentile). It is likely (60+% chance) that the northwestern half of the North Bay gets wetting rain (0.10 inches) between now and then. While rainfall is expected to be beneficial, wet roadways will create slick driving conditions and increase stopping distance.
..issued at 1250 PM PDT Mon Aug 31 2026 (Saturday through Sunday)
Global ensemble clusters diverge on solutions dramatically going into the weekend, specifically on low vs trough and the location and timing of the feature, so basically everything. What is certain is that the region will be under the influence of some kind of troughing through the weekend. As it weakens through the weekend, a gradual warming and drying trend will commence with temperatures moderating to slightly below to near normal. Beyond the seven day forecast and into Labor Day/early next week, Invest EP95 well offshore of Southwestern Mexico becomes a variable. Uncertainty over the weekend will compound and propagate into the tropical side of the forecast, making it impossible to talk specific impacts at this point in time. The primary impacts would likely be rain and wind with impacts likely decreasing from south to north.
(06z TAFS) Issued at 1019 PM PDT Mon Aug 31 2026
MVFR stratus has lingered through the day across portions of the SF Bay Area, and is beginning to expand again across the North Bay and into the Monterey Bay region. High clouds may interrupt the radiational cooling across portions of the South Bay and Central Coast, but a very deep marine layer should support stratus decks heading far inland through the course of the night. Stratus should clear back to the immediate coast through the course of Tuesday morning into the early afternoon, with a gentle to moderate onshore pattern wind developing in the afternoon and evening hours. Tuesday night, lower confidence in stratus impacts as the fringes of a decaying front begin to impact the region, with a shift to a more southwest wind flow expected as the front or its remnants approach. Chances for rain in the North Bay lie just after the end of the 24- hour TAF period.
Vicinity of SFO, MVFR stratus with gentle southwest winds through the night and into Tuesday morning. Moderate confidence in a moderate westerly breeze developing in the afternoon and evening hours on Tuesday, with winds turning to the southwest and the south through the evening and overnight periods. Low confidence of MVFR ceilings Tuesday night before the end of the TAF period, with greater confidence in low-end VFR clouds over the terminal.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, MVFR to low-end VFR ceilings persist through the latter part of Tuesday morning. A gentle onshore wind persists through the afternoon and evening, with the winds turning from the southwest over MRY tonight to the west for the afternoon and evening. Low confidence in a return of stratus to SNS Tuesday night as winds diminish.
(tonight through next Sunday) Issued at 1019 PM PDT Mon Aug 31 2026
Gentle westerly to northwesterly breezes persist through the week with intermittent periods of moderate breezes. Wind driven seas remain slight to moderate through the week with long period southerly swells persisting thanks to tropical cyclone activity.
Ca, None. PZ, Small Craft Advisory until 3 AM PDT Tuesday for SF Bay N of Bay Bridge.
