textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1231 AM PDT Wed Sep 30 2026

- Elevated fire weather conditions across the higher terrain through Thursday

- Areas of moderate HeatRisk across the interior through Tuesday

- Minor coastal flooding for bayshore locations along the San Francisco, San Pablo, and Monterey Bays Monday through Thursday

SHORT TERM

Issued at 1231 AM PDT Wed Sep 30 2026 (Wednesday through Thursday)

With ridging nosing in from the Eastern Pacific Ocean and a low across the Desert Southwest, the upper-level pattern will support northerly/offshore flow through Thursday. Northerly/offshore winds will be strongest during the overnight periods and in the higher terrain. Mt. St. Helena gusted to 48 mph Tuesday morning with gusts of 25-35 mph elsewhere, similar conditions can be expected during the overnight periods through Thursday morning. The combination of dry and windy conditions will result in elevated fire weather conditions across the higher terrain through Thursday. Temperatures will be 5 to 10 degrees above normal with the marine layer struggling to form. If it is able to form, it will be compressed around 500 feet and remain confined to the coast. Minor coastal flooding for bayshore locations along the San Francisco, San Pablo, and Monterey Bays will continue during the highest high tides through Thursday.

LONG TERM

Issued at 1231 AM PDT Wed Sep 30 2026 (Friday through Tuesday)

Global ensemble clusters are in agreement that anomalously high heights will be across our area through Tuesday. 500 mb heights and 850 mb temperatures are forecast to be near the 90th percentile for the first week of October, which is 588 decameters and 21 degrees Celsius, respectively. Saturday will likely be the peak of the heat as upper-level longwave ridging drifts in from the Eastern Pacific Ocean. Nonetheless, temperatures will be 10 to 15 degrees above normal with moderate HeatRisk away from the immediate coast through Tuesday. The marine layer will likely still struggle to form; if it's able to form, it will be compressed around 500 feet and remain confined to the coast.

AVIATION

(06Z TAFS) Issued at 954 PM PDT Tue Sep 29 2026

Currently VFR except MVFR at HAF. Moderate confidence on LIFR conditions returning to the coastal terminals of HAF, MRY, and SNS with lower confidence in the return at APC and STS, elsewhere VFR. With stratus well offshore, this will likely be achieved via radiational cooling. The best chances are between 08Z and 16Z, more specifically when radiational cooling maximizes around sunrise (14Z). Diurnal winds will prevail. Haze will reduce slant range visibilities.

Vicinity of SFO...Currently VFR with westerly flow. High confidence in VFR and diurnal winds prevailing through the TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently VFR with southwesterly flow at MRY and VFR with northerly flow at SNS. Moderate confidence on LIFR conditions returning tonight, best chances are between 08Z and 16Z. Diurnal winds will prevail.

MARINE

(Tonight through next Monday) Issued at 954 PM PDT Tue Sep 29 2026

Hazardous conditions for small craft will continue through Wednesday night across the outer waters and coastal jet regions of Point Reyes and Point Sur. Frequent northerly gale force gusts will continue tonight across the northern outer waters. Conditions will improve Thursday and into the weekend as northerly breezes diminish to become gentle to moderate. Rough to very rough seas Wednesday will subside to become moderate by Friday.

FIRE WEATHER

Issued at 515 AM PDT Mon Sep 28 2026

The marine layer persists this morning, around 1500-2000ft, but should gradually compress to around 500ft throughout the day. Today will be coolest day of the week, though it is also the start of a warming trend. Offshore flow gradually works its way into the region today, which will lead to breezy winds each morning from through Wednesday. The strongest winds are expected on Tuesday morning in the interior mountains of the North and East Bays, where wind gusts could reach 30-35 mph. These offshore winds should contribute to poor overnight humidity recoveries, with overnight relative humidities as low as 20-40% above the marine layer.

MTR WATCHES/WARNINGS/ADVISORIES

CA...Coastal Flood Advisory until 5 PM PDT Thursday for CAZ006-506- 508-529-530.

PZ...Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 3 AM PDT early this morning for Pt Pinos to Pt Piedras Blancas 0-10 nm.

Gale Warning until 9 AM PDT this morning for Pt Arena to Pt Reyes 10-60 NM.