textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1147 AM PDT Thu Sep 3 2026

- Well below normal temperatures with beneficial rain Thursday

- Hazardous beach conditions at Pacific Coast beaches Friday through Monday

- Below normal temperatures through the weekend, gradual warming and drying trend Monday through Wednesday

SHORT TERM

Issued at 1147 AM PDT Thu Sep 3 2026 (Thursday through Thursday night)

Cloud cover will increase through the day as a cold front approaches from the northwest. FROPA will occur this afternoon into this evening from northwest to southeast. The standard wind shift from southeasterly to northwesterly will occur pre and post-frontal, respectively, with gusts up to 25 mph to be expected. Gusts of 30-40 mph are expected through terrain favored gaps and passes such as The Delta, Altamont Pass, and Pacheco Pass, as well as down the Salinas Valley. For the North Bay, rainfall totals up to 0.25" with locally higher amounts up to 0.75" in the higher terrain are expected. South of the Golden Gate Bridge, less than 0.10" is expected with accumulation favoring the coast and higher terrain with the help of orographic lift. Overperformance is still a possibility with the struggles of guidance/models in the early season. While rainfall is expected to be beneficial, wet roadways will create slick driving conditions and increase stopping distance. With ample low-level moisture and post-frontal clearing, the marine layer will try to reform tonight. As a result, patchy fog/stratus will be possible for the Friday morning commute.

LONG TERM

Issued at 1147 AM PDT Thu Sep 3 2026 (Friday through Wednesday)

The most impactful weather phenomenon Friday through Monday will be hazardous conditions at Pacific Coast beaches. Two sets of long period southerly swell from distant Hurricane Karina and Hurricane Marie will result in an increased risk for sneaker waves and strong rip currents with breaking waves up to 10 feet. With pleasant sensible weather expected, these are the type of days that are most deadly; with it being the Labor Day holiday weekend, that will likely only make matters worse. If you want an outdoor activity this weekend, hit the trails instead of the beach. There's good agreement through the weekend that there will be an upper-level low over the Pacific Northwest which will keep our region under the influence of troughing. As such, expect below normal temperatures and onshore flow to continue with the return of the marine layer. The forecast is now dry this weekend with the farther west track of Marie and dry air filtering in from the northwest. Uncertainty arrives Monday in terms of low versus trough, but global ensemble clusters are in agreement that the pattern becomes progressive again as the low begins to fill and move east. This will allow for ridging to build in from the Desert Southwest, kicking off the gradual warming and drying trend. It is now looking likely that at least some of Marie's remnant moisture will eventually be brought into our area as soon as Tuesday. Whether this transpires as clouds or rainfall will be dependent on the reinforcing low/trough and the strength of the flanking ridges. Right now, the official forecast has light rainfall Tuesday through Thursday favoring the Central Coast.

AVIATION

(00Z TAFS) Issued at 556 PM PDT Thu Sep 3 2026

The front is slowly meandering across northern CA this evening, with light to moderate rain being observed across the North Bay. Chances for rain will gradually decrease through the evening hours for terminals up there, while chances increase slightly for the rest of the Bay Area terminals this evening. The front begins to fizzle out as it advances towards the Central Coast, so lower cigs and perhaps some virga might be all we get. Behind the front, northwest winds usher in drier air. This makes any sort of fog/stratus forecast tough for tonight. Opted to keep the trends from the previous met, and have them arriving during the early overnight hours for most sites. But that could be too optimistic and we'll need to re- evaluate with the 6Z package.

Vicinity of SFO...SFO has bewildered us today with the low clouds being quite pesky, and if you didn't guess it, that remains the forecast challenge this evening. As the front passes, expect periods of reduced cigs and perhaps some VCSH. VCSH should come to an end between 03Z-05Z which may bring us a break in the periodic MVFR cigs. After that, the HREF, HRRR, and NAM show moisture lingering around KSFO all night and into tomorrow morning. The question will be, do we get socked in with MVFR cigs or to we clear out a bit? Opted to keep the pessimistic forecast for the time being with conditions improving around or shortly after sunrise. Any low clouds that linger should erode by mid to late morning. Breezy onshore winds return for the afternoon and early evening hours, with sustained speeds around 12-15kt with gusts up to 22-25kt possible. Low to medium confidence in the low cloud forecast through sunrise.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...The front will slowly approach the region tonight, bringing with it some mid and high level clouds. Ahead of it, some stratus has formed on the northern side of the Monterey Bay, while KSNS and KMRY remain cloud free. Models show the chance for stratus building in between 01-04Z, with the front arriving later. Looking at MVFR to IFR cigs tonight around the region, with skies gradually clearing Friday morning.

MARINE

(Tonight through next Wednesday) Issued at 556 PM PDT Thu Sep 3 2026

Rain chances diminish over the northern waters through the night. Gentle to moderate northwesterly breezes will persist across the waters in wake of a weak frontal passage. However, diurnal fresh to strong gusts return within the Monterey Bay and along the Big Sur Coast Friday into the weekend. More widespread fresh to strong gusts return by early next week across the coastal waters. Long period southerly swell associated with tropical activity well to our south will reach the coastal waters Friday and continue into early next week.

BEACHES

Issued at 1010 PM PDT Wed Sep 2 2026

A Beach Hazards Statement is in effect Friday-Monday as the swell from both Hurricane Marie and Hurricane Karina reaches the coast. As these hurricane whip up the ocean, the waves travel over 1,000 miles in all directions, gradually flattening out to low amplitude, but long period swell. These waves aren't very intimidating if you're on a boat in the open ocean, but the long period allows them to push much farther up the beach. Long period swell always increases the chance for sneaker waves, but that's particularly true this weekend since there are 2 different sets of southerly swell, and their energy will periodically combine. In addition to sneaker waves, expect strong rip currents and breaking waves up to 10 ft. As this is a holiday weekend and the weather is otherwise pretty nice, the exposure to the risk is high. Avoid the water if you're not an expert swimmer. If caught in a rip current, swim parallel to shore until you stop feeling the pull. Even on the beach, be prepared for sneaker waves this weekend and never turn your back on the ocean.

MTR WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement from Friday morning through Monday evening for CAZ006-505-509-529-530.

PZ...None.