textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1201 AM PDT Fri Sep 11 2026

- Temperatures near seasonal averages through the next week

- Breezy onshore winds this weekend

SHORT TERM

Issued at 1201 AM PDT Fri Sep 11 2026 (Today and tonight)

What a difference a day makes. The continuing development of a cutoff low off the coast of British Columbia has led to a remarkable cooling through the evening and overnight hours, the return of a marine layer of around 500-1000 feet, and a stratus deck over the coastal regions and through the Petaluma Gap and the Golden Gate. As of midnight, temperatures across the Bay Area and Central Coast are running around 5 to 25 degrees below what they were 24 hours prior. Through the day, the aforementioned cutoff low will strengthen as it parallels the coast of the Pacific Northwest. Morning lows will range from the middle 50s to lower 60s in the lower elevations, and the middle 60s to the middle 70s in the higher elevations, while afternoon highs will top out in the middle 80s to the lower 90s in the inland valleys, the upper 90s to the triple digits in the warmest spots of southern Monterey County, the upper 60s to the lower 80s close to the Bays, and the lower to middle 60s along the Pacific coast.

LONG TERM

Issued at 1201 AM PDT Fri Sep 11 2026 (Saturday through Thursday)

The cooling trend continues into the weekend as the cutoff low moves into the Pacific Northwest, allowing for further development of the onshore flow and marine layer to take place. By the weekend, highs will drop into the middle 70s to middle 80s inland and the upper 60s to upper 70s close to the Bays. Breezy onshore winds are expected through the weekend as the passing cutoff low tightens the pressure gradient over the northern half of California. Regarding the SFO-WMC gradient, model output has kept the peak gradient somewhere in the 10 to 15 mb range late on Saturday, with widespread gusts of 25 to 35 mph possible Saturday evening into Sunday morning. Favored gaps, passes, and coastal regions could see gusts to 45 mph.

The trough axis should move into the northern Rockies and the northern Plains for the early part of next week, but the general pattern should remain rather zonal for the remainder of the 7-day outlook, and temperatures should remain more or less stable with highs near or slightly below seasonal averages.

AVIATION

(12Z TAFS) Issued at 429 AM PDT Fri Sep 11 2026

As expected the marine layer has returned and is bringing IFR to LIFR stratus to the coastal terminals. The 12Z balloon just measured the marine layer depth at 1600 feet, which is deep enough to reach SJC, but not LVK. APC is still VFR, but could go either way at this point. The stratus will clear around 18-19Z for all but the coastal terminals. HAF will likely stay IFR or worse through the entire TAF period. Stratus will return to most terminals overnight.

Vicinity of SFO...The terminal is reporting IFR ceilings, which will persist through at least 17Z, and possibly through 19Z before VFR conditions return through the afternoon. A moderate onshore breeze will arrive this afternoon. Stratus is likely to return between 06Z and 12Z tonight.

SFO Bridge Approach...Ceilings will clear a couple hours earlier than the terminal, and form a couple hours later.

Monterey Bay Terminals...LIFR conditions will persist through the morning. SNS will very likely clear by late morning, but MRY is more of a toss up. If there is any clearing at MRY, it will only last for 6 hours or so before the marine layer stratus returns.

MARINE

(Today through Wednesday) Issued at 429 AM PDT Fri Sep 11 2026

A moderate to fresh NW breeze will increase over the next 24 hours, with a fresh to strong breeze expected through the weekend and into next week. Seas are currently moderate and will build to rough by Monday in response to the stronger winds.

FIRE WEATHER

Issued at 429 AM PDT Fri Sep 11 2026

A new weather pattern will influence conditions over the Timber and Plaskett Fires in Monterey County. The marine layer has returned and is 1,600 feet deep as measured by the 12Z balloon. This height should be fairly consistent through the day before some expansion this weekend as the trough moves through. While the marine layer brings much cooler and more humid conditions to the coast, areas above the marine layer often experience nocturnal drying as the dry air above the clouds rolls in simultaneously with the low clouds. In the late morning the clouds will mix out as the layers become less stratified, often increasing dew point during the warmest part of the day.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory from 9 AM to 3 PM PDT Saturday for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm- SF Bay N of Bay Bridge.

Small Craft Advisory until 3 PM PDT Saturday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory from 9 AM this morning to 9 PM PDT this evening for Pigeon Pt to Pt Pinos 0-10 nm.