textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1248 PM PST Fri Dec 12 2025

- Hazardous beach conditions through the evening

- Impacts from Tule Fog continue in the North Bay and interior East Bay valleys

- Wetter conditions expected next week

SHORT TERM

Issued at 1248 PM PST Fri Dec 12 2025 (This evening through Saturday)

Persistent stratus and fog continues across the valleys of the North Bay and interior East Bay, with the clouds continuing to mix out throughout the afternoon and into the early evening hours, when the Tule Fog outgrowth returns to the Bay Area. To the south, a southerly surge is developing to the west of San Luis Obispo County, and will travel northwards along the Big Sur coast, flow into the Monterey Bay region, and progress along the San Mateo coast through the evening and overnight hours. Continuing to opt for a more persistent forecast for high temperatures today, with highs in the Central Coast valleys reaching the lower to middle 70s, the Bay Area valleys reaching the upper 50s to lower 60s barring the northern and eastern parts of the interior East Bay, where highs reach the middle 40s to near 50, and highs across the higher elevations into the lower to middle 70s. Overnight, expect lows in the upper 30s to middle 40s for the valley regions, and the middle 40s to the lower 50s in the higher elevations. Dense Fog Advisories may need to be issued early Saturday morning for the inland valleys, but also the immediate coast depending on the evolution of the Tule Fog and southerly surge through the next day.

By Saturday, the ridge that has brought us the last few days of stable conditions will begin move off to the east, with the coastal stratus retreating to the immediate coastal region. How the Tule Fog will react to the change isn't all too clear. The current forecast shows a similar clearing pattern to today's. High temperatures are currently expected to remain nearly the same as today's in the lower elevations, perhaps a couple of degrees cooler in the higher elevations.

LONG TERM

Issued at 1248 PM PST Fri Dec 12 2025 (Saturday night through next Thursday)

As we head into the early part of next week, the ridge continues to move to the east and a pattern change brings more zonal flow to the region by Tuesday. This new pattern should help scour out the Tule Fog and, when combined with a plume of moisture with PWAT values up to 1.2 inches, brings a chance of light rain to the region Tuesday and Wednesday, focused on the North Bay. A weak ridge will move through the state on Thursday and Friday, but the overall flow should remain generally zonal and lingering showers and drizzle are possible from remnant moisture in the region.

Beyond the 7-day outlook, the forecast points towards another round of wet weather across the region for the weekend of the 20th and 21st as a deep trough in the eastern Pacific coincides with another plume of moisture moving through the West Coast. The CPC outlooks are leaning towards precipitation totals above the seasonal average in their latest 6-10 day outlooks (from December 18th to the 22nd, 55-70% probability), giving the region a moderate chance for heavy rain and high winds (40-60% probability of total rainfall and sustained winds reaching the 85th percentile of the seasonal distribution) starting on the 20th. For context, when taking the long-term averages, December is the wettest month for downtown San Francisco with monthly average precipitation of 4.76 inches. We have not seen a drop of rain since the 20th of November, and for the 6-10 day outlook, the expected rainfall total lies somewhere around three quarters of an inch of rain. The chances for rain don't stop that weekend: CPC outlooks maintain the lean towards precipitation totals above seasonal averages in the 8-14 day outlook (December 20th-26th, seasonal average of over an inch of rainfall at downtown San Francisco), the moderate chances for heavy rain and high winds mentioned earlier in this paragraph extend through the 26th, and the ensemble mean products suggest a lingering trough in the eastern Pacific through this period, a pretty notable signal especially this far out into the forecast.

AVIATION

(18Z TAFS) Issued at 927 AM PST Fri Dec 12 2025

LIFR conditions persist over the North Bay, East Bay and South Bay this morning while the Bay Area and Monterey Bay terminals remain VFR. The aforementioned LIFR conditions are forecast to improve by late morning or early afternoon and give way to VFR conditions. Overnight, tule fog/stratus is likely to return to the North Bay and East Bay late tonight and South Bay early Saturday morning. Looking like there is greater probability of a southerly surge to impact the Monterey Bay terminals early Saturday morning.

Vicinity of SFO...VFR conditions through the TAF period. There is generally less than a 20% probability for IFR conditions early Saturday morning across the Bay Area terminals, but not high enough to include in the current TAF. Any low clouds and/or fog that do develop are anticipated to be short lived with clearing by 18-19Z Saturday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Light onshore winds will return by mid-afternoon before easing after sunset. There is a greater probability for sub-IFR conditions beginning late tonight and into Saturday morning as a southerly surge moves up along the Big Sur coast.

MARINE

(Today through Wednesday) Issued at 838 AM PST Fri Dec 12 2025

Gentle NE winds will gradually shift to southerly by Saturday morning as moderate to rough seas subside to a slight 3 feet from Saturday through Monday. These favorable conditions are rare for winter. A moderate westerly swell will return by Tuesday with moderate westerly winds arriving Wednesday.

BEACHES

Issued at 1214 AM PST Fri Dec 12 2025

Long period NW swell is causing hazardous beach conditions Friday. This energy brings strong rip currents, an increased risk for sneaker waves, and large breaking waves. This coincides with nice warm weather, which will likely lure more people to the beach under a false sense of security. A Beach Hazard Statement is in effect through Friday evening. Respect the power of the ocean and never turn your back on it.

MTR WATCHES/WARNINGS/ADVISORIES

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

PZ...None.