, Issued at 1247 AM PST Sun Nov 9 2025 (Today and tonight)
Mostly clear conditions continue overnight with large scale offshore flow keeping the lower atmosphere relatively dry, although some stratus and fog development is possible in the North Bay valleys and far eastern Contra Costa county. Low temperatures tonight range from near 50 within wind-sheltered valleys, to the middle 50s for the rest of the lower elevations and the upper 50s to lower 60s along the thermal belts. The weather pattern today should continue to be warm, clear, and dry underneath a large scale ridge, with highs reaching 10 to 20 degrees above seasonal averages away from the immediate coastal area. High temperatures are forecast around the lower to middle 80s in the inland valleys, except in the Morgan Hill- Hollister corridor and the southern Salinas Valley where temperatures reach the upper 80s to near 90, while the bays see highs in the upper 70s to lower 80s and the Pacific coast reaches the upper 60s to lower 70s. Although this is a lower confidence outcome (around a 10-20% probability), there is some scope for significantly warmer temperatures on the western side of the coastal ranges and the Berkeley-San Leandro hills, particularly if stronger offshore flow develops than the current forecast. In the event that these scenarios develop, the 75th percentile high temperatures (25% chance of warmer temperatures) remain a degree or two above the current forecast for the immediate San Francisco Bay region, while the 90th percentile (10% chance of warmer temperatures) jump into the middle to upper 80s.
..issued at 1247 AM PST Sun Nov 9 2025 (Monday through Saturday)
The ridge remains established through Monday, when highs similar to or a couple degrees above today's forecast are expected, with similar caveats if offshore flow comes in stronger than the current forecast. Overnight, the thermal belts remain active through Tuesday morning, resulting in mild overnight lows and offshore winds across the higher terrain.
On Tuesday, the ridge begins to erode and shuffle to the east, starting a cooling trend that will bring highs down around 2 to 5 degrees across the region, with the most pronounced cooling at the coastal areas. By Wednesday, the decaying ridge should allow a deep trough developing across the eastern Pacific to enter the West Coast and bring a period of unsettled weather to the region. In terms of this particular trough, the unsettled regime comes in two parts. First, the most intense rain band comes through the region late on Wednesday into Thursday. This does bring in widespread rainfall across the Bay Area and Central Coast, but the exact totals, and thus downstream effects on flooding and landslide risk, are still in question. For the period from 4 AM Wednesday to 4 AM Friday, the NBM gives the following ranges for 25th to 75th percentile rainfall totals (that is, a 50% probability that the eventual rainfall falls within this range): 1.0"-1.9" at Sonoma County Airport and San Francisco International Airport, 0.8"-1.5" at San Jose Airport, and 1"-1.7" at the Livermore Airport and Monterey Regional Airport. The NBM is also keeping a 10-20% probability of thunderstorms across the Bay Area and Central Coast Wednesday night into Thursday, and the ECMWF is forecasting K-Index values up to 30-35 degrees Celsius, suggesting that scattered thunderstorms are possible.
After the main rain band moves out late Thursday, an extended period of lighter rain, possibly showery in nature, lingers Friday into the upcoming weekend. The axis of the upper level trough crosses into the state early on Friday, promoting unstable conditions resulting in the possible development of convectively driven showers. There is also a chance that a cut-off low could develop off the coast of southern California, which could enhance the rain potential across the Central Coast. That said, with the moisture tap moving to the south and into southern California and Baja California, there will be less moisture for the showers to tap into, and the rain totals for this part of the system trend lower than those on Wednesday and Thursday. The precipitation chances start out around 40-60% on Friday morning and steadily decrease into Saturday.
Beyond the 7 day outlook, ensemble model means are suggesting another trough may develop somewhere around the Day 8-9 (the 16th and 17th) timeframe, bringing another chance of rain to the region. This far out, attempting to tease out any further details is a fool's errand.
(12z TAFS) Issued at 301 AM PST Sun Nov 9 2025
Patchy dense fog has been persistent in the vicinity of KSTS, with LIFR/IFR vis expected through mid-morning. Otherwise, the remainder of our terminals are VFR with relatively weak offshore flow through the forecast period.
Vicinity of SFO, Similar to SFO.
SFO Bridge Approach, VFR is expected through the forecast period with light westerly surface winds this afternoon and evening becoming light and variable late tonight into early Monday morning.
Monterey Bay Terminals, VFR conditions are expected through the TAF period with breezy valley winds at KSNS this morning, becoming onshore in the afternoon. A southern surge of stratus gradually moving up the Big Sur coastline may bring MVFR ceilings later this afternoon into the evening to KMRY. Confidence in potential and timing is too low attm for mention in the TAF. Drainage valley winds return to KSNS this evening into early Monday morning.
(today through Friday) Issued at 301 AM PST Sun Nov 9 2025
*Synopsis from previous forecaster: Favorable conditions in the short term with rough conditions later this week. A gentle to moderate northerly breeze and moderate NW swell will continue through Tuesday. Late Wednesday winds will flip to southerly and increase to a strong breeze across the coastal waters. Winds will remain moderate to strong and gradually veer back to NW through the day Thursday. These winds, combined with a building NW swell, will generate rough waves. While the winds decrease Friday, the high swell continues to build with significant wave heights reaching up to 15 feet before diminishing through the weekend.
Ca, None. PZ, None.
