textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 129 AM PDT Sun Aug 31 2025

- Moderate risk for heat-related illnesses today and Monday

- Elevated fire weather concerns across the interior mountains into Monday with low RH and moderate onshore winds each afternoon

- Hazardous coastal conditions through Monday night due to long period southerly swell

SHORT TERM

Issued at 129 AM PDT Sun Aug 31 2025 (Today and tonight)

Mostly clear skies will persist today and tonight. A drier airmass combined with a compressed marine layer will result in spotty stratus development confined to only the coastline, if there is any at all. Temperatures will increase slightly for many locations this afternoon from Saturdays highs. A Heat Advisory is not warranted, but people visiting any of the numerous inland and elevated recreational areas in our forecast area should be aware of the warm temperatures and plan accordingly. Stay hydrated, seek shade, take breaks and dont leave people or pets in vehicles. Breezy onshore flow this afternoon will also result in elevated fire weather concerns, see below for more information.

LONG TERM

Issued at 129 AM PDT Sun Aug 31 2025 (Monday through Saturday)

A weak upper level low continues to gradually approach from offshore. The weak disturbance will draw in improved mid-level moisture between H50-H70. We will continue monitor the non-zero chance for elevated convection Monday into Tuesday. As the upper level disturbance approaches the coast, it is likely to evolve into a negatively tilted open wave. As of right now, the best lift is out of phase and north of the improving mid-level moisture that is expected to be in place, however subtle changes in the timing and position of the disturbance could lead to increasing chances of elevated thunderstorms. Lightning and gusty winds would be the primary concern. Beyond Tuesday, the moderate heat begins to ease through mid-week, with notable cooling by the end of the week into next weekend.

AVIATION

(12Z TAFS) Issued at 409 AM PDT Sun Aug 31 2025

VFR through the day. Breezy onshore winds develop this afternoon with gusts at 15 to 20 knots, before diminishing this evening. High resolution models are suggesting that stratus and fog return to the immediate coastal region tonight through Monday morning. Confidence on impacts to the terminals is moderate for HAF and MRY, and low everywhere else.

Vicinity of SFO... VFR through the TAF period. Breezy west-northwest winds develop this afternoon and evening gusting up to 25 knots knots. A few high resolution models are suggesting that stratus returns to the terminal area early Monday morning, but confidence is very low.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... VFR through the day with breezy onshore winds developing this afternoon and evening. Moderate confidence that stratus and fog return to the immediate coastal area and MRY tonight, potentially extending beyond the end of the TAF period.

MARINE

(Today through Friday) Issued at 409 AM PDT Sun Aug 31 2025

Fresh to strong northwesterly breezes continue through the weekend with strong gusts and thus hazardous conditions for small craft across much of the waters. Moderate to fresh northwesterly breezes will prevail Monday through Wednesday. Moderate seas persist through Wednesday.

FIRE WEATHER

Issued at 129 AM PDT Sun Aug 31 2025

Warm and dry conditions will continue today and Monday, especially for locations above 500ft. Widespread MinRH values between 10%-20% combined with occasional wind gusts up to 30 MPH will result in elevated fire weather concerns. We are also monitoring the potential for elevated thunderstorms Monday afternoon into Tuesday. Chances are low at the moment, but if the pattern evolves with improved timing of the mid-level moisture and best lift associated with the upper level disturbance we could see some isolated convection across portions of the Bay Area, East Bay Hills and North Bay.

BEACHES

Issued at 939 PM PDT Sat Aug 30 2025

A Beach Hazards Statement is in effect through 11PM Monday due to long period (18 seconds) southwesterly swell causing an increased risk for sneaker waves and rip currents along southwest facing beaches, including but not limited to: Stinson Beach, Santa Cruz Boardwalk Beach, and Twin Lakes Beach. Sneaker waves can unexpectedly run significantly farther up the beach than normal, including over rocks and jetties. Rip currents are typically more frequent and stronger in the vicinity of jetties, inlets, and piers. It is always important, but especially so on a warm, dry, holiday weekend, to exercise caution while at the beach. Never turn your back on the ocean, remain out of the water to avoid hazardous swimming conditions, keep pets on a leash, and wear a life jacket.

Sarment

MTR WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement through Monday evening for CAZ505-509- 529.

PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for Mry Bay.

Small Craft Advisory until 9 PM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Monday for Pt Reyes to Pigeon Pt 0-10 nm.

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

Small Craft Advisory until 9 AM PDT Monday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

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