textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 120 PM PST Tue Nov 25 2025

- Dry and mild conditions continue through Thursday

- Cooler temperatures Friday and into the weekend as the next system approaches

- Gusty offshore winds are possible by the end of the weekend and into early next week

UPDATE

Issued at 851 PM PST Tue Nov 25 2025

And here we go again. Temps are falling to or near to the dewpoint temp, which means that the relative humidity is at or approaching 100%, which means saturation yielding haze or fog. In addition, the winds are very light. Looking at observations around the area Santa Rosa is already reporting 2 SM, Napa 1.5 SM, and Livermore 5 SM. Will likely do a quick update to the forecast to expand the fog farther west. Apart from that, the forecast remains on track this evening.

SHORT TERM

Issued at 120 PM PST Tue Nov 25 2025 (This evening through Wednesday)

Low clouds persist over the North Bay and East Bay, yet are forecast to begin clearing later this afternoon. However, if they do not, temperatures will be cooler than currently forecast by up to 10 degrees. Elsewhere, temperatures are forecast to reach into the 60s across most inland areas while the immediate coastal areas of the North Bay and San Francisco Peninsula remain in the mid-to-upper 50s.

As offshore flow persist in the higher elevations across the region, the marine layer remains compressed. Thus, there is greater probability for less coverage of fog overnight. However, still expecting patchy to areas of dense fog across the North Bay valleys, East Bay valleys, and the Santa Clara Valley overnight. Temperatures overnight are forecast to be mostly in the 40s with the coldest interior spots potentially lowering into the upper 30s.

As the ridge axis shifts eastward into southern California, temperatures will continue to warm on Wednesday. This is when we are expecting temperatures across the interior Central Coast, Santa Cruz area, southern Santa Clara and Hollister valleys, and far inland North Bay valleys to reach or exceed 70 degrees F. These temperatures will be up to 10 degrees above seasonal averages. Again, similar to today, areas that do not see afternoon sunshine will likely be a few to several degrees cooler.

LONG TERM

Issued at 120 PM PST Tue Nov 25 2025 (Wednesday night through next Monday)

On Thursday, an upper level trough is forecast to approach the Pacific Northwest brining unsettled weather to that area. Locally, we are forecast to see similar temperatures as Wednesday for daytime highs. By Friday, this feature will shift into the northern part of the Intermountain West, thus cooling temperatures to near seasonal averages as a weak, dry back door cold front sweeps across the Bay Area and Central Coast. A reinforcing trough will drop out of British Columbia and act as an inside slider setup as in drops southward across the Intermountain West. This would lead to gusty offshore winds across our region. However, exact details reamin difficult to pin down at this time as there remains uncertainty this far out. Be sure to check back and keep up-to-date with the latest forecast information.

AVIATION

(06Z TAFS) Issued at 948 PM PST Tue Nov 25 2025

Fog is starting to make its way into the North Bay and East Bay. Confidence is moderate to high in fog impacting STS, APC, and LVK overnight, moderate confidence it will reach OAK, SJC, and SNS, and low confidence in fog reaching SFO, HAF, and MRY. STS and APC have already reported fog with cameras showing fog filling in across the East Bay. Current thinking is that if sites do start to develop fog, visibilities and ceiling heights will drop rapidly. Winds stay light and offshore overnight before becoming more northwesterly to northerly during the day. Light, offshore winds redevelop overnight with potential for fog to return again.

Vicinity of SFO...VFR through the TAF period. Confidence is low that fog will extend across the SF Bay tonight and reach SFO. Current thinking is that fog will not be as expansive tonight as it was last night with fog more limited to the North Bay and interior East Bay. Winds stay light and offshore overnight before moderate onshore winds return during the day. Winds weaken and shift offshore again overnight with guidance suggesting some potential for lower visibilities and ceilings tomorrow night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR at MRY, VFR potentially becoming IFR at SNS overnight. For MRY - fog is not expected to reach the terminal tonight with winds remaining light and generally offshore through the TAF period. For SNS - leaned on persistence to show fog potential for tomorrow morning. The key thing to watch for is if fog will fill in across the southern Salinas Valley and gradually flow south to north. SNS looks to develop moderate SE drainage winds early tomorrow morning which could help bring fog northwards towards the airport. If fog does not develop in the southern portions of the valley, drainage winds could keep the atmosphere too well mixed to allow for fog formation at SNS.

MARINE

(Tonight through next Monday) Issued at 948 PM PST Tue Nov 25 2025

High pressure over off the California Coast will maintain gentle to moderate northerly conditions through mid week. Patchy dense fog will be possible again tonight, especially in the bays. Seas will continue to subside through Wednesday. Winds will begin to increase again late week, building moderate to rough seas.

MTR WATCHES/WARNINGS/ADVISORIES

CA...Dense Fog Advisory until 11 AM PST Wednesday for CAZ510.

PZ...None.