Issued at 850 PM PDT Wed Sep 2 2026
No changes to the forecast this evening as we watch the cold front slowly drift southwards. Rain remains well to our north via radar, though high clouds have started move overhead. In between the breaks of the high clouds, satellite has shown some stratus developing along the coast and in some valleys. Will need to keep an eye on that and see how it pans out for the aviation forecast.
, Issued at 1159 AM PDT Wed Sep 2 2026 (This afternoon through Thursday)
KMUX shows a band of light precipitation bisecting the Bay Area and moving east. Still waiting on a bucket tip south of the Golden Gate Bridge; nonetheless, it won't amount to much as the band continues to weaken. This pre-frontal rain has overperformed the official forecast with Mt. Tam measuring 0.57" in the last 24 hours. The overperformance is likely due to the struggles of guidance/models in the shoulder seasons. The cold frontal passage will occur tomorrow afternoon/evening from northwest to southeast, bringing renewed chances for rainfall alongside well below normal temperatures and cloudy conditions. This second round of rain also runs the risk of overperformance; however, the forecast has trended wetter. Totals of 0.10"-0.50" for most of the North Bay and 0-0.10" south of the Golden Gate Bridge are expected with accumulation south of the Golden Gate Bridge primarily favoring the San Francisco Peninsula Coast. Looking at the 90th percentile, totals get bumped up with up to 1.00" possible in the higher terrain of the North Bay and up to 0.50" along the San Francisco Peninsula Coast. While rainfall is expected to be beneficial, wet roadways will create slick driving conditions and increase stopping distance. Wind Advisory criteria is not expected to be met; however, gusts of 30-40 mph can be expected through gaps/passes and down the Salinas Valley.
..issued at 1159 AM PDT Wed Sep 2 2026 (Friday through next Tuesday)
A cutoff low will spawn in the Pacific Northwest from remnant upper- level troughing as ridging expands westward into the Desert Southwest. The low is expected to fill through the weekend, giving the ridge increasing influence over the forecast. As such, a gradual warming and drying trend and the reformation of the marine layer is expected over the weekend. These features will also be enough to shunt moisture from Tropical Storm Marie south of the California Bight, at least for now. Even with a cutoff low in play, there is relatively good agreement in the forecast through Monday. By Tuesday, the ECMWF and GFS begin to drastically diverge on their solutions with Marie. The one to watch will be the ECMWF as it has another cutoff low digging, absorbing, and bringing what was Marie into Central California, which would be a low probability outlier at the moment. It's imperative to note that if it reaches California: Marie will no longer be tropical and the primary impact will be rainfall.
(06z TAFS) Issued at 957 PM PDT Wed Sep 2 2026
Minimal changes to the TAF package this evening. The near term changes covered stratus that has started to form along the coast and in some of the valleys. Outside of that, we await the arrival of a cold front. The highest chances for rain will be for the North Bay terminals with chances decreasing around the San Francisco Bay. Heavier pockets of rain may bring reduced visibility at times, but most sites will see at least MVFR to potentially IFR cigs with the passage of the front. VFR cigs may return as early as the late morning areas for some terminals, for North Bay terminals. Clearing skies will gradually follow for terminals south of there, with a slot for clear skies. Models hint at stratus trying to reform late Thursday night into Friday morning but confidence was too low to add to most terminals.
Vicinity of SFO, Stratus formed off the west side of the San Francisco Peninsula and around KOAK this evening; however, KSFO has been lucky with only high clouds being reported. Confidence remains low with the stratus forecast here, so opted to remain optimistic during the overnight hours. Though lower clouds are expected with the passage of the front. We'll be watching the frontal passage, which should reach the San Francisco area Thursday morning. The best chances for rain look to be between 14-20Z with perhaps some vicinity showers or MVFR type cigs lingering into the mid afternoon. Winds will be from the south early on and getting to about 15kt by the late morning or early afternoon. Flow becomes west/northwest once the front passes, with sustained 15kt winds through roughly sunset. Cigs should gradually improve with the frontal passage as well.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, The HRRR seems to be doing alright this morning, capturing the blip of stratus hugging the northern portion of the Monterey Bay and slinking into the northern Salinas Valley. Models show stratus flirting around KSNS for the next couple of hours, with stratus returning after midnight but clearing shortly after sunrise. Brought cigs up a bit to MVFR levels rather than keeping them at IFR given last nights observations, but the marine layer and stratus have humbled us before. Nonetheless, it should be short lived as it retreats to the coast during Thursday morning and a front slowly meanders southward. VFR cigs are expected by 13-15Z Thu, with high clouds returning to the forecast for the afternoon. Around or shortly after 0Z Fri, stratus looks to make are return to KSNS and KMRY.
(tonight through next Tuesday) Issued at 850 PM PDT Wed Sep 2 2026
A weak cold front will move through the region late tonight and into Thursday morning. Winds will continue to shift ahead of its arrival with gentle to moderate southwest breezes expected. Rain chances are best north of Pigeon Point during the morning and early afternoon hours, with isolated showers possible down to Point Pinos during the afternoon. Northwest winds return behind the front and will be gentle to moderate. Diurnal winds increase more Friday and Saturday afternoon, especially in vicinity of Monterey Bay. The tropical activity well to our south will produce long period southerly swell beginning Friday and continuing through the weekend into the beginning of next week.
Ca, Beach Hazards Statement from Friday morning through Monday evening for CAZ006-505-509-529-530.
PZ, None.
