, Issued at 1200 PM PST Sat Dec 6 2025 (This evening through Sunday)
The current satellite image shows dissipating stratus across the Santa Clara Valley and the San Francisco Bay Shoreline, while the City and the valleys of the North Bay and interior East Bay remain socked in the spillover from the Tule Fog across the Central Valley. Towards the western parts of Sonoma and Marin counties, the Tule Fog spillover merges with marine layer stratus. The trend of the last couple of days has been the models struggling to accurately reflect the evolution of the Tule Fog in the North and East bay valleys. Model output shows the stratus deck beginning to dissipate over the North Bay valleys now, but that does not appear to be happening. I have tamped down the highs for today and tomorrow across the Bay Area in response to the model's struggles. The current forecast has today's highs in the upper 50s across the Bay Area valleys, with central and eastern Contra Costa County and far eastern Alameda County seeing highs in the lower to middle 50s. This does assume that the stratus does eventually mix out this afternoon, and if the stratus lingers through the day, the North and East bay valleys might not get out of the 40s. Tomorrow's forecast currently has the highs warming by a couple of degrees, within a couple degrees of 60 for most of the area, but this is highly dependent on how the Tule Fog evolves tonight into Sunday morning, and could also need to be dropped if the stratus sticks around long enough tomorrow.
Meanwhile, over in the Central Coast the skies are clear, have remained generally clear this morning, and will remain clear during the afternoon and evening hours. Model output is showing some possibility for stratus to develop in the Monterey Bay region and northern Salinas Valley tonight. While is some reason to second- guess the model output, for the reasons stated above, those reasons lean towards more stratus being present than the current forecast. However, any influence from the Tule Fog will be limited to the far eastern reaches of San Benito and southern Monterey Counties, where the Gabilan Range abuts the Central Valley. Highs in the Central Coast reach the middle to upper 60s in the inland valleys, to the lower to middle 60s closer to Monterey Bay, perhaps into the lower 70s in some of the sheltered valleys within the Santa Lucia and Gabilan ranges.
..issued at 1200 PM PST Sat Dec 6 2025 (Sunday night through next Friday)
Ridging will dominate the weather patterns through the rest of the 7- day outlook, enabling a gradual warming trend across the region. The highs will peak around the later part of the upcoming work week with highs in the inland valleys reaching the middle 60s to middle 70s, around 8 to 13 degrees above the seasonal average. As with the short term forecast, the biggest source of uncertainty will be how the Tule Fog develops every night and morning, impacting the temperatures across the North and East Bay valleys. The deterministic forecast has the East Bay interior valleys remaining in the lower to middle 60s, but depending on how the Tule Fog evolves the temperatures could easily vary by around 10 degrees on either side of the current forecast.
A couple of storm systems will approach the West Coast during the 7- day outlook, but the ridging pattern will deflect the brunt of the storms to the Pacific Northwest and leave us with a chance of drizzle in the coastal waters while land areas remain dry. Longer range model guidance suggests a possible change in the weather pattern towards the middle of the month. Ensemble model cluster analysis continues to show some of the model members (somewhere around 30-40% of the ensemble members) depicting a breakdown of the ridge. however, most of the ensemble members and the ensemble means point to the ridge persisting over the western United States, or flattening out into a zonal flow pattern. Uncertainty remains rather high in this part of the forecast and we will keep an eye on what the trend from later model runs turns out to be.
(00z TAFS) Issued at 416 PM PST Sat Dec 6 2025
Low clouds and fog continue in the North Bay and interior East Bay. Expect cloud cover in these areas to lower further into the night and the fog to become thicker. The SF Bay terminals as well as SJC see CIGs arrive overnight with some slight reductions in visibilities. Winds stay mostly light to moderate through the morning, with wind directions determined by more localized affects. Cloud cover and fog will be slow to erode into Sunday, but conditions look to improve into the afternoon. However, the North and East Bay will continue to struggle with low clouds and fog, causing some doubt for clearing at STS and LVK, while APC doesn't look to clear for Sunday afternoon. While over sites see less chances for low clouds and fog into that afternoon, pockets of haze will affect much of the region.
Vicinity of SFO, VFR lasts into early Sunday morning. Moderate northerly winds become lighter and more westerly into the night before becoming more variable into early Sunday morning as IFR CIGs fill over the terminal. CIGs scatter in the mid morning, and moderate northwest winds arrive that afternoon.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR through the TAF period. Winds stay light for MRY through the TAF period, while SNS sees moderate northwest winds become light into the early night. Expect winds to turn southeast overnight. Northwest winds return Sunday afternoon with the potential for haze along the coast.
(tonight through next Friday) Issued at 416 PM PST Sat Dec 6 2025
Strong to near gale force gusts will be possible through the end of the weekend, with breezy northwest winds lasting into the middle of next work week. Moderate seas with wave heights 6 to 8 feet across the outer waters this weekend. A new, long period northwesterly swell is anticipated by Wednesday of next week.
Ca, Coastal Flood Advisory until 3 PM PST Sunday for CAZ006-506-508- 529-530.
PZ, Small Craft Advisory from 3 PM to 9 PM PST Sunday for Pigeon Pt to Pt Pinos 0-10 nm.
Small Craft Advisory until 9 PM PST this evening for Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory from 9 AM Sunday to 3 AM PST Monday for Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 3 AM PST Sunday for Pigeon Pt to Pt Pinos 10-60 NM.
Small Craft Advisory from 9 AM to 9 PM PST Sunday for Pigeon Pt to Pt Pinos 10-60 NM.
