textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 856 AM PDT Sat Sep 12 2026

- Breezy onshore winds Saturday afternoon through Sunday afternoon

- Temperatures near seasonal averages through next week

UPDATE

Issued at 856 AM PDT Sat Sep 12 2026

As mentioned in the Short Term section of the AFD below, a weak frontal boundary that moved across the North Bay and Bay Area yesterday evening scoured out low-level marine layer clouds. However, the marine layer on the 12Z OAK Upper Air Sounding reported the marine layer depth at around 1,500 feet. Thus, stratus was confined to the Monterey Bay Region, down the Salinas Valley and just off of the Big Sur coastline. These low clouds are forecast to dissipate throughout late morning and early afternoon. All that said, the ongoing forecast remains on track at this time with no updates anticipated this morning.

RGass

SHORT TERM

Issued at 1017 PM PDT Fri Sep 11 2026 (Tonight through Saturday night)

Satellite imagery reveals something pretty peculiar for this time of year, so soon after the marine layer redeveloped after a couple days of heat: clear skies across most of the Bay Area and Central Coast, as a weak frontal boundary helped to scour out the marine layer clouds over the afternoon and evening hours. Observations from the Bodega Bay profiler suggest that the marine layer itself is still there, hovering around 1000-1500 feet, so it remains to be seen if any of the remaining stratus, most notably the patch on the eastern side of Monterey Bay, can linger through the night, and whether any new stratus can form overnight. Looking at the high resolution output, it doesn't seem likely and many of us may see the skies remain clear overnight.

A strong cutoff low hovers off the coast of the Pacific Northwest, helping contribute to the cooling trend that started Thursday night and continued through the following day. Through Saturday the cutoff low is expected to inch its way into the state of Oregon, helping to tighten the local pressure gradient and building breezy and strong onshore winds in the afternoon and evening hours on Saturday before winds ease Sunday morning. Wind gusts will generally reach 25 to 35 miles per hour, with favored gaps, passes, valleys, and coastal areas seeing gusts to 45 miles per hour.

Morning lows will hover in the middle 50s to lower 60s for the lower elevations, and into the middle 60s for the higher elevations. Afternoon highs range from the upper 70s to middle 80s for the inland valleys, up to the 90s in the warmest spots of the far interior Central Coast, the upper 60s to the middle 70s close to the Bays, and the lower to middle 60s along the Pacific coast.

LONG TERM

Issued at 1017 PM PDT Fri Sep 11 2026 (Sunday through next Friday)

The trough axis continues moving eastwards Sunday into the early part of next week, helping to relax the pressure gradient and lower the wind gusts for Sunday. Despite the trough axis moving into the northern Rockies and Plains, some troughing influence will remain across the West Coast, keeping temperatures near to slightly below seasonal averages. The pattern will remain remarkably stable through the remainder of the 7-day outlook. Highs will range from the middle 70s to the middle 80s inland, the upper 60s into the 70s close to the Bays, and the lower to middle 60s along the Pacific coast. Low clouds will likely develop overnight into the morning, while breezy onshore winds will set up in the afternoon and evening hours. Longer- term outlooks suggest a lean towards temperatures above seasonal averages and precipitation totals near to above seasonal averages towards the latter part of September.

AVIATION

(12Z TAFS) Issued at 524 AM PDT Sat Sep 12 2026

It's VFR except for patchy stratus and mist/fog /MVFR-LIFR/ this morning. Surface to lower level cool air advection on northwest winds will increase today, the wind flow trapped beneath a lower level temperature inversion resulting in areas of strengthening, gusty onshore winds. The SFO-SAC pressure gradient is forecast to increase to 4 mb to 5 mb in the afternoon. September sun angle surface warming and vertical mixing will erode any remaining stratus by late morning. Gusty onshore winds may continue through the evening before diminishing tonight.

Vicinity of SFO...VFR. West wind 5 knots increasing to 25 to 35 knots in the afternoon, continuing through the evening and may take to 3 am Sunday before diminishing to 15 knots.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR except patchy stratus and mist/fog /IFR-LIFR/ nearby during the morning. Onshore winds 5 knots increasing to 10 to 20 knots with occasional gusts to 25 knots in the Salinas Valley late morning, afternoon and early evening. Winds diminishing to 10 knots tonight and Sunday morning.

MARINE

(Today through Thursday) Issued at 856 AM PDT Sat Sep 12 2026

Hazardous conditions for small craft prevail this weekend through the middle of next week. Winds increase today with a strong breeze to develop by early Sunday and continue into the middle of next week. Widespread near gale force gusts are likely Sunday into early Monday with gale force gusts are expected along the inner waters from Pigeon Point to Point Piedras Blancas, the Monterey Bay, and in portions of the San Francisco and San Pablo Bays. Moderate seas will build, becoming rough by Monday in response to the stronger winds.

FIRE WEATHER

Issued at 625 AM PDT Sat Sep 12 2026

The marine layer remains around 1,500 feet in depth per 12Z OAK Upper Air Sounding. However, the stratus pattern does not represent this as mostly clear sky conditions prevail early this morning with stratus hugging the southern portion of the Monterey County coastline. However, overnight humidity recoveries have been good to excellent in elevations generally below 1,500 feet. Above that, humidity levels remain largely in the teens and twenties as of 6 AM PDT Saturday. Thus, not expecting much humidity retention this afternoon with the higher elevations not forecast to exceed 25-35%. The depth of the marine layer will hold steady between 1,000-1,500 feet through the weekend. Areas above the marine layer often experience nocturnal drying that will likely continue into early next week.

RGass

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory until 9 AM PDT Sunday for SF Bay N of Bay Bridge.

Small Craft Advisory from 3 PM to 9 PM PDT Sunday for SF Bay N of Bay Bridge.

Small Craft Advisory until 3 PM PDT Sunday for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm.

Gale Warning from 3 PM to 9 PM PDT Sunday for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm.

Small Craft Advisory until 3 AM PDT Monday for Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 3 AM PDT Monday for Pt Reyes to Pigeon Pt 0-10 nm.

Small Craft Advisory until 9 PM PDT this evening for Pt Pinos to Pt Piedras Blancas 0-10 nm.

Gale Warning from 9 PM this evening to 9 PM PDT Sunday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory until 9 AM PDT this morning for Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory from 3 PM Sunday to 3 AM PDT Monday for Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM.