textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1103 AM PDT Wed Sep 23 2026

- Warming trend continues into Thursday bringing pockets of moderate HeatRisk across parts of the Bay Area and north Central Coast.

- Cooler conditions arrive Friday into the weekend.

- Near seasonal temperatures early next week.

SHORT TERM

Issued at 1157 PM PDT Wed Sep 23 2026 (Tonight through Friday)

There is a large variation in temperatures across our forecast area, with 50s in a shallow marine layer along the coastline and 60s, 70s and near 80 inland and at elevation. The warmth is due to ongoing thermal and height ridging aloft while a narrow channel of cooler air over the coastal waters is undercutting the ridge. There is very little to no stratus or fog over the coastal waters since there is also warmer surface to near surface air temporarily mixing in on northwest winds. Even though it's dry aloft i.e. good conditions for outward radiative cooling to help stratus and fog develop, the air/sea interface is not thermodynamically supportive of stratus/fog at the current time. However, 1000 mb NAM forecasts a rapidly southeastward moving cooler air mass arriving in our coastal waters between midnight and Thursday morning, which may briefly fall into syncopation with the remaining rhythm of radiative cooling in the early morning. This combination will likely help produce a few areas of coastal stratus and fog, while inland areas stay clear since the marine layer depth is forecast to remain near steady.

Daytime highs on Thursday will warm up similarly to Wednesday's daytime highs with mid 60s to 70s near the immediate coastline, 70s/80s bayside to the 90s well inland.

The ridge will weaken Friday with onshore winds deepening, sending cooler air inland. Daytime highs Friday will range from the 60s/70s coastside to the 80s well inland.

LONG TERM

Issued at 1157 PM PDT Wed Sep 23 2026 (Friday night through next Wednesday)

For the weekend, 500 mb troughing will return once again which will keep temperatures cooler than normal for late September. It should be a beautiful weekend temperature-wise. After the weekend cooling trend, temperatures will warm up again by the middle of next week.

AVIATION

(06Z TAFS) Issued at 934 PM PDT Wed Sep 23 2026

A relatively weak but compressed marine layer continues to maintain VFR conditions across our area. Coastal sites are expected to see MVFR/IFR ceilings develop after midnight with interior locations like KSTS and KSJC possibly not seeing stratus/fog until closer to sunrise. VFR is expected area wide by mid/late Thursday morning.

Vicinity of SFO...MVFR ceilings are expected to develop during the overnight hours, with high confidence in VFR conditions by mid- morning Thursday. Gusty onshore flow develops in the afternoon and will continue into the late evening hours. A fetch of weak offshore flow late in the forecast period may limit stratus development into early Friday morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR/LIFR ceilings are expected to develop around or shortly after midnight and persist through mid-morning Thursday with VFR conditions expected through the remainder of the TAF period into late Thursday evening.

MARINE

(Tonight through next Tuesday) Issued at 934 PM PDT Wed Sep 23 2026

North to northwest breezes will continue tonight, with strong gusts developing Thursday afternoon that will persist through Friday, especially Friday afternoon and evening from nearshore Santa Cruz to Big Sur with seas responding and becoming rough into the weekend.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory until 5 AM PDT early this morning for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 3 AM PDT Thursday for Pt Arena to Pt Reyes 10-60 NM.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory from 9 AM to 9 PM PDT Friday for Mry Bay.

Small Craft Advisory from 3 PM Thursday to 9 AM PDT Saturday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory from 9 PM Thursday to 9 AM PDT Saturday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory until 3 AM PDT Thursday for Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory from 3 AM Friday to 3 PM PDT Saturday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.