textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 144 PM PST Mon Nov 24 2025

- Dry and mild conditions continue until the end of the week

- Cooler temperatures this weekend as the next system approaches

- Gusty offshore winds are possible by the end of the upcoming weekend

SHORT TERM

Issued at 252 AM PST Tue Nov 25 2025 (Today and tonight)

Primary concern in the short term is the dense fog that has developed overnight across the North Bay Interior Valleys and East Bay Interior Valleys, and may eventually have to be expanded further as we head toward and through sunrise. Attm a Dense Fog Advisory is in effect for the North Bay Interior Valleys and East Bay Interior Valleys until 11AM this morning.

An offshore surface high pressure under broader ridging aloft is pulling a weak fetch of offshore flow across much of our area today and tomorrow. Subsidence beneath the ridge should keep a shallow marine layer just offshore this afternoon and evening area wide, resulting in a nice day. Todays temperatures will be similar to yesterday for the North Bay and Bay Area, slightly warmer for inland areas over the Central Coast where morning fog won't be as extensive. Patchy dense fog is expected to develop once again later tonight into the overnight hours over the North Bay Interior Valleys, however coverage should decrease as drier air associated with the shifting ridge mixes closer to the surface.

LONG TERM

Issued at 252 AM PST Tue Nov 25 2025 (Wednesday through Monday)

Gradual warming through the middle of the week remains on track with temperatures peaking on Thursday afternoon while a progressive trough to our north continues to quickly get deflected north and east of our area. Weak amplified ridging aloft over the Pacific Northwest on Friday won't stop a weak back door cold front from pushing south through our area during the day Friday, cooling most areas off by a few degrees. The forecast for the weekend and beyond lacks consensus, but cooler temperatures than what we'll see the next few days seems likely as the longwave synoptic pattern becomes highly amplified, allowing for cooler Canadian air to filter south across the entire West Coast.

AVIATION

(06Z TAFS) Issued at 938 PM PST Mon Nov 24 2025

Conditions vary from VFR to LIFR including a few areas of hazy skies this evening. A shallow cool frontal boundary is moving southward over the coastal waters while low ceilings, fog and tule fog are slowly advancing back into our easternmost forecast area. A stable air mass including a lower precipitable water (0.52") on the 00z (4 pm) Oakland upper air sounding compared to 0.72" 12z (4 am) this morning favors improving radiative cooling tonight and Tuesday morning. Light offshore winds per SAC-SFO 0.8 mb and WMC- SFO 2.1 mb support a reversal of maritime influence we had over the weekend (which helped limit dense fog coverage), with an increasing continental influence reaching into our forecast area, including a tule fog intrusion from the east tonight and Tuesday morning. So far not seeing any numerical weather prediction mesoscale models showing any significant boundaries forecast to disrupt the light offshore wind pattern Tuesday morning which may allow the fog intrusion to the Bay Area to linger during the day, minus incoming solar heating Tuesday. This may favor a positive feedback loop of more dense fog Tuesday night/Wednesday morning.

Vicinity of SFO...VFR likely continues through the evening. There's an increasing probability 20%-30% of IFR per recent HREF between 09z-16z Tuesday, 00z/06z SFO TAF has tempo IFR ceiling 13z-17z Tuesday, but caveat is persistent light NE-E wind may transport even lower conditions to VLIFR-LIFR during this time. It's a low confidence forecast since it's still many hours from now, however weather conditions and the time of year (plus recent generous early season rain) are all favorable for aforementioned conditions and it needs to be closely monitored. As such, it is a low confidence forecast as to the return and duration of VFR Tuesday, if the model forecasts are under-forecasting the extent of fog it may take longer to mix out to VFR than currently 17z advertised in the TAF.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Low to moderate confidence VFR continues through late evening and overnight here. Current satellite imagery supports VFR forecast to late evening at least. Nocturnal radiative cooling will set up cool air drainage winds for tonight and Tuesday morning providing a mixing wind to help prevent the development of stratus and/or fog. Cool front and air mass passes by to our west, HREF/HRRR model ouput show dry, cool air drainage mixing winds and VFR prevailing tonight and Tuesday morning. VFR continues Tuesday afternoon with winds gently shifting back to light onshore in the mid to late afternoon. Low confidence VFR forecast Tuesday evening.

MARINE

(Today through Sunday) Issued at 252 AM PST Tue Nov 25 2025

Dense fog has developed across the West Delta, into the San Pablo and San Francisco Bays, creating hazardous conditions for mariners through the morning hours. High pressure will persist over the coastal waters through mid to late week. Seas will gradually ease through the middle of the week with gentle to moderate northerly breezes. Winds will begin to increase again late week, building moderate to rough seas.

BEACHES

Issued at 923 PM PST Mon Nov 24 2025

The Beach Hazards Statement has been extended through 10 AM PST Tuesday. A long period northwesterly swell will result in an increased risk for sneaker waves and rip currents. Breaking waves of 13 to 18 feet are expected. 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.

MTR WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement until 10 AM PST this morning for CAZ006- 505-509-529-530.

Dense Fog Advisory until 11 AM PST this morning for CAZ506-510.

PZ...Dense Fog Advisory until 11 AM PST this morning for SF Bay N of Bay Bridge.