textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 843 PM PDT Thu Sep 10 2026

- Cooler temperatures, closer to seasonal averages, Friday into the weekend

- Breezy onshore winds this weekend

UPDATE

Issued at 843 PM PDT Thu Sep 10 2026

Temperatures are cooling rapidly across the region and some marine layer stratus has arrived to the immediate coastal areas. While some interior locations remain relatively warm, further cooling is expected through the night and especially on Friday night, and high temperatures on Friday are not expected to be as high as today's. As a result, we have cancelled the Heat Advisory.

DialH

SHORT TERM

Issued at 1215 PM PDT Thu Sep 10 2026 (This evening through Friday night)

After a warm start to the day, the interior will remain very warm to hot with the ongoing Heat Advisory still in place until 10 PM PDT this evening. However, we are already seeing cooler conditions near the coast as a shallow marine layer is forecast to return as well as an increase in onshore winds.

Tonight, temperatures are forecast to cool into the mid 50s to near 60 deg F near the coast and across the interior valleys. However, the higher elevations look to only cool into the 70s and potentially the lower 80s. Coastal stratus and/or fog look to develop along the coast and potentially into the North Bay Valleys overnight as the marine layer deepens to around 500 feet.

On Friday, depending on how much stratus/fog develops in the morning, the cooling trend will continue with temperates moderating to near seasonal averages with mostly sunny conditions across the interior. This is a result of the mid/upper level through deepening off of the Pacific Northwest coast and high pressure over the Desert Southwest being suppressed to the south.

LONG TERM

Issued at 1215 PM PDT Thu Sep 10 2026 (Saturday through next Wednesday)

The gradual cooling trend will continue into the weekend as the low pressure off of the Pacific Northwest coast deepens further, bringing rainfall to that region. This will allow the marine layer to deepen as well, reaching around 1500 feet by Saturday night into Sunday. This would also bring increased afternoon and evening winds in the favored valleys, peaks, passes, and gaps.

Beyond this weekend, troughing off of the West Coast looks likely to persist. This will allow for afternoon maximum temperatures to be near to slightly below average and overnight minimum temperatures to be near or slightly above.

AVIATION

(06Z TAFS) Issued at 935 PM PDT Thu Sep 10 2026

Shallow marine layer is hugging the coast and beginning to slowly ooze inland. Initial impacts are mainly to HAF with IFR conditions. IFR will prevail well into Friday for HAF with some sct late Friday evening. Elsewhere, VFR will persist for the first few hours tonight before stratus move farther inland dropping cigs to MVFR/IFR, except far inland LVK/SJC/APC. VFR expected tomorrow afternoon. Some uncertainty in the extended as the marine layer struggle with a strengthening n to s tightening gradient. Overall conf is moderate. Marine layer depth will likely be in the 700-1000 foot range.

Vicinity of SFO...VFR. Will bring cigs in late with some impacts to the Friday AM rush. Clearing will be early Friday afternoon.

SFO Bridge Approach...Similar to SFO. Far S end of approach may be more SCT than BKN/OVC Friday AM.

Monterey Bay Terminals...Eddy is forming in the bay, which may delay initial push of stratus but expecting cigs by Friday morning. Clearing to VFR will be mid afternoon.

MARINE

(Tonight through next Wednesday) Issued at 843 PM PDT Thu Sep 10 2026

Northerly flow will increase over the coastal waters through Friday leading to moderate to fresh breezes. Winds will increase further this weekend and become fresh to strong. The stronger winds will produce locally hazardous conditions for small craft Moderate seas will prevail through the weekend, building to become rough in the outer waters Monday. A longer period southerly swell will mix into the sea state due to tropical systems in the Pacific.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory from 3 AM Friday to 3 AM PDT Saturday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

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

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