textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 320 AM PDT Sat Jul 5 2025

- Temperatures remain below seasonal averages into early next week.

- Gradual pattern change bringing warming trend for second half of next week begins Wednesday.

- Marine layer increases and expands farther inland for end of the weekend, beginning of next week.

UPDATE

Issued at 1007 AM PDT Sat Jul 5 2025

Made a small tweak to the forecast this morning to account for the eroding stratus. Guidance shows it potentially lingering along the San Mateo and San Francisco coasts and perhaps the Monterey Peninsula area today, with mainly sunny skies expected elsewhere.

SHORT TERM

Issued at 320 AM PDT Sat Jul 5 2025 (Today and tonight)

A weak upper level disturbance has begun to split off from the northern jet across the Pacific Northwest and will gradually develop into a cut-off low later tonight, and settle off the Central Coast by early Sunday morning. Dry air just above the marine layer continues to make the coastal stratus cloud cover forecast difficult. A sliver of low stratus can be seen at this hour (3AM PDT) building south from the Bay Area toward the San Lucia coastal range, bypassing the Monterey Bay at the moment. Expect stratus to remain mostly confined to coastal locations where it does develop with little inland intrusion. Todays temperatures will continue to be on the cool side with bright sunshine inland and slacking wind compared to previous couple days.

LONG TERM

Issued at 320 AM PDT Sat Jul 5 2025 (Sunday through Friday)

A cut off upper level low will stall off the California Central Coast over the next few days. As the weak upper system slowly meanders offshore we should see an improved fetch of moisture above the marine layer up to approx 500mb, resulting in an expanding marine layer that will penetrate farther inland as we head into the beginning of next week. Early morning drizzle and fog may also be more widespread for the beginning of next week. By Wednesday the stalled upper low begins to make progress inland. Considerable uncertainty remains in the forecast for a potential warm up late next week, however expect temperatures by the end of next week into next weekend to at least rebound closer to normal, with eyes on some potential moderate heat risk if the synoptic pattern supports longer residence time of ridging aloft over our region late in the extended forecast.

AVIATION

(18Z TAFS) Issued at 1026 AM PDT Sat Jul 5 2025

IFR to MVFR at MRY and HAF this morning with the greatest likelihood to scatter out at MRY. HAF may maintain ceilings through the TAF period. Onshore winds increase again this afternoon with high confidence for IFR to MVFR ceilings returning late tonight across the Monterey Bay terminals as the marine layer deepens. Moderate to high confidence for MVFR ceilings to develop around the Bay Area terminals early Sunday morning and persist through about 17Z-18Z Sunday. Onshore winds increase again Sunday afternoon, however and forecast to be weaker than previous days.

Vicinity of SFO...VFR. Onshore winds will increase this afternoon with gusts to around 25 kt. Moderate to high confidence for MVFR (potentially lowering to IFR) Sunday morning. Low clouds will scatter out by around 17Z-18Z Sunday with onshore winds once again increasing by Sunday afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals... VFR. Onshore winds will increase slightly this afternoon before easing after sunset. High confidence for IFR/MVFR ceilings to develop around the terminals late this evening and potentially lowering to LIFR early Sunday morning.

MARINE

(Today through Thursday) Issued at 1026 AM PDT Sat Jul 5 2025

Moderate seas and a fresh to strong northwesterly breeze will continue through the remainder of the weekend. Winds will diminish late Sunday into Monday with a moderate breeze to continue through late next week. Occasional gale force gusts are possible along the Big Sur coastline Saturday afternoon. Winds increase and significant wave heights build beginning late next week.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for SF Bay N of Bay Bridge.

Small Craft Advisory until 9 PM PDT this evening for Mry Bay.

Small Craft Advisory until 9 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.

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

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