Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

523 pm PST Wed Dec 3 2025

Short Term

, Issued at 1213 PM PST Wed Dec 3 2025 (This evening through Thursday)

Satellite imagery shows extensive high clouds across the Central Coast, medium-level clouds across the Bay Area south of the Golden Gate, and a thinner layer of high clouds across the North Bay. Across the higher elevations, strong northeasterly winds continue to gust up to 45 to 50 mph across favored locations, more generally around 25 to 35 mph. These are being driven by the interaction between a positively tilted trough extending from the Upper Midwest into the Desert Southwest and an upper level ridge off the coast of the Pacific Northwest and British Columbia. The combination results in northerly flow over the region and a offshore pressure gradient, although with the trough starting to move eastwards, the gradient is gradually relaxing. The SFO-WMC gradient, which peaked at -8.9 mb as of 7 AM this morning, has slackened to -6.3 as of Noon. Model guidance shows the gradient continuing to gradually relax over the next 24 hours. Another push of offshore flow is expected tonight, but the gusts will not be as strong and the winds should return to a more northwesterly onshore flow tomorrow.

High temperatures today and tomorrow will hover in the upper 50s to the middle 60s for the lower elevations, down to the lower to middle 50s in the higher elevations. Lows will reach the upper 30s to the lower 40s in the inland valleys, and into the middle to upper 40s along the coast. Chilly lows in the lower to middle 30s are expected in the southern reaches of Monterey County, but the coverage is not widespread enough, especially across the southern Salinas Valley, to issue a Cold Weather Advisory.

Long Term

..issued at 1213 PM PST Wed Dec 3 2025 (Thursday night through next Tuesday)

The forecast conditions remain remarkably stable with the conditions remaining generally dry and benign through the 7 day outlook. Although a couple of storm systems will impact the West Coast, the upper level flow will divert them to the north. As a result, while the Pacific Northwest and the North Coast see a couple shots of rain, the current forecast depicts the rain chances for our part of the state remaining offshore, sometimes tantalizing close to the shoreline. The eastern Pacific ridge will build into the southwestern US during this time, allowing a gradual warming trend to begin on Friday and last through the weekend. By the early part of next week, temperatures in the inland valleys could rise into the upper 60s to lower 70s, with the coast remaining in the lower to middle 60s.

The next chance for substantial rainfall across the region lie closer to the middle of the month, and at this point in the forecast, the uncertainty can be best described as "Here be dragons". Considering that the moisture to power such a system currently lies in the western Pacific and the parent low pressure system has yet to form over Asia, this is not surprising.

Aviation

(00z TAFS) Issued at 523 PM PST Wed Dec 3 2025

Light, generally light offshore winds and VFR conditions continue through the TAF period. Sites are running anywhere between 15% to 50% drier today than they were at this time yesterday. This influx of dry air should keep both marine stratus and foggy conditions away from our area tonight. The one concern would be if any Tule Fog is able to redevelop and move into the delta/towards APC. Not currently expecting this to occur but it is a possibility if fog is able to redevelop in the Central Valley. A weak sea breeze is possible tomorrow afternoon and evening again.

Vicinity of SFO, VFR through the TAF period. A weak sea breeze is expected to develop this afternoon/evening and again tomorrow afternoon/evening. Otherwise, winds largely remain light and offshore through the TAF period. Not expecting any low clouds or fog either at SFO or along the Bridge Approach.

SFO Bridge Approach, Similar to SFO.

Monterey Bay Terminals, VFR. Winds remain lightly onshore through the rest of the evening before becoming offshore again overnight. Winds transition to lightly onshore/more northerly by late tomorrow morning/early tomorrow afternoon.

Marine

(tonight through next Tuesday) Issued at 523 PM PST Wed Dec 3 2025

Moderate NW winds will persist through the afternoon and decrease to a gentle breeze by Thursday. Rough seas in the outer waters will gradually diminish overnight as the winds ease and westerly swell abates. After a brief favorable weather window on Thursday, northerly winds will increase to a fresh to strong breeze on Friday, rebuilding moderate seas up to 8 feet.

Beaches

Issued at 425 AM PST Wed Dec 3 2025

A Beach Hazards Statement remains in effect for the coastline from Sonoma County to Monterey County through 10 PM PST Wednesday evening. Breaking waves 10 to 14 feet, with long lulls of 10 to 20 minutes or more between largest sets can be expected. Some of the favored break points may exceed 20 feet at times. Forerunners will be 18+ seconds with heights of 2-5 feet into tonight resulting in the greatest risk for sneaker waves. This combined with high astronomical tides in the morning hours will increase the aforementioned risk. 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.

RGass

Watches, Warnings, Advisories

Ca, Beach Hazards Statement until 10 PM PST this evening for CAZ006- 505-509-529-530.

Coastal Flood Advisory until 3 PM PST Sunday for CAZ006-506-508- 529-530.

PZ, Small Craft Advisory from 9 PM Thursday to 3 PM PST Friday for Pt Arena to Pt Reyes 10-60 NM.

Visit this site often? Consider supporting us with a $10 contribution.
Learn more