Issued at 855 PM PST Mon Dec 8 2025
A strong 500 mb high pressure system (585 decameter height) remains over the forecast area. This continues to result in dry weather. Large scale compressional warming of air within the high continues to result in close to 90th percentile (or slightly greater) temperatures at each of the mandatory pressure levels from 925 mb to 500 mb on the Oakland upper air sounding for the time of year. This warmth is aloft, with milder to warmer temperatures also over our forecast area at ground level where it remains clear/sunny during the day, an early December Sun angle heat input reaching the ground connecting and mixing with warm air availability just overhead near the temperature inversion. However, this air mass stability is also resulting in a much different story near and at ground level where fog and stratus prevail much if not all day e.g. in the East Bay and the North Bay valleys, also reaching the San Francisco Peninsula on mainly light offshore winds; it's been markedly chillier on a daily basis in these areas since November 25th.
For the time being high pressure remains in control of our area's weather, which extends through the rest of the week with some weakening of the high over the weekend, but only marginally with 500 mb heights barely lowering below 580 decameters.
, Issued at 243 PM PST Mon Dec 8 2025 (This evening through Tuesday)
The stagnant pattern continues with the story being cloudy conditions returning tonight for areas that cleared around the Bay Area and clear conditions for much of the Central Coast. This should keep low temperatures generally in the 40s for Bay Area counties and Santa Cruz County. Elsewhere in the Central Coast, lows will vary from the upper 30s to low 40s for the interior portions, while c coastal areas sit closer to the mid 40s. A new forecast challenge also arrives for tonight as temperatures were a bit chillier than expected last night for the northern Salinas Valley and along the coast of the southern Monterey Bay area. For now kept NBM in for the lows; however, should temps drop like last night they may need to be adjusted a few degrees cooler.
..issued at 243 PM PST Mon Dec 8 2025 (Tuesday night through next Sunday)
High pressure holds through the week, leading to dry conditions through the weekend. Temperatures should warm by mid week, before cooling a bit again over the weekend. The next chance for rain looks to be around December 15, where the NBM favors the best chances of rain around the North Bay with a 15-20% expanding to the East and South Bay counties and into Santa Cruz County. Ensembles do show the ridge flattening some which could allow a front to make it into the region. The details will likely change, so stay tuned.
(06z TAFS) Issued at 948 PM PST Mon Dec 8 2025
Low clouds and fog have reformed in the North Bay and interior East Bay. SFO and SJC see CIGs arrive in the late night with some slight reductions in visibilities. Winds stay mostly light to moderate through the TAF period, with wind directions determined by more localized affects. Cloud cover and fog will be slow to erode into Wednesday afternoon, but conditions look to improve into the late afternoon. However, the North and East Bay will continue to struggle with low clouds and fog, causing some doubt for clearing at APC. As cloud cover erodes, pockets of haze will affect much of the region. Winds reduce again into Wednesday evening with fog and low cloud looking again to reform in the North Bay and interior East Bay.
Vicinity of SFO, VFR lasts into the late night. Winds become lighter into the night with scattered low clouds building into the area, along with some slight reduction in visibilities. IFR level CIGs fill into the late night with some weak easterly winds. Cloud cover thins into the afternoon, but winds stay light and turn slightly more northerly. These wind look to become light and variable into the late evening.
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 westnorthwest rebuild into Wednesday afternoon. These winds become light and variable into that night.
(tonight through next Sunday) Issued at 948 PM PST Mon Dec 8 2025
North and northwest flow continues with moderate to fresh winds continuing south of Point Sur. Winds increase to a strong breeze Tuesday into mid week across the outer waters. A new, long period northwesterly swell is expected by midday Wednesday,lasting into the early weekend.
Ca, None. PZ, Small Craft Advisory until 9 PM PST Tuesday for Pt Pinos to Pt Piedras Blancas 0-10 nm.
