textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 246 AM PST Mon Jan 19 2026

- Dry weather, cool mornings, and warm afternoons this week

- Morning fog across the Delta, North Bay Valleys, and interior East Bay Valleys

SHORT TERM

Issued at 246 AM PST Mon Jan 19 2026 (Today and tonight)

Patchy fog is developing in the North Bay Valleys with intermittent reports of dense fog (1/4 statute mile visibility or lower) coming in from KSTS (Santa Rosa Airport) and KDVO (Novato/Gnoss Field Airport). Will hold off on a Dense Fog Advisory for now as the areas of dense fog are localized/not widespread on the webcam footage. If anyone is commuting in the North Bay Valleys, East Bay Valleys, or along the San Pablo/Suisun Bay and Delta areas this morning, be aware of the potential for dense fog, be prepared for sudden changes in visibility, and remember to slow down.

High pressure remains the name of the game. A ridiculously resilient ridge remains fixed over the West Coast with temperatures running anywhere from 5 to 15 degrees above normal for this time of year. High temperatures on Sunday were generally in the mid to upper 60s across the lower elevations of the Bay Area, upper 60s to low 70s across the higher elevations, and low to upper 70s across the Central Coast. The temperature distribution for today looks to be fairly similar with highs in the mid to upper 60s across the Bay Area and upper 60s to mid 70s throughout the Central Coast. Guidance shows a shallow (500 ft) marine layer developing tonight which may bring additional fog and low clouds to portions of the coastline tonight. Winds remain light and offshore through midweek.

LONG TERM

Issued at 246 AM PST Mon Jan 19 2026 (Tuesday through Sunday)

Ridging sticks around through at least midweek before an upper level trough pushes in late Wednesday into Friday. This upper level trough will develop as a cut-off low and move southwards along the California coastline late this week. Unfortunately, this system looks to be dry with no rain expected from this system. PWAT values are between 0.7"-0.8" with a slightly stronger moisture tap entering southern California (where models show the potential for light rain). In the wake of this cut-off low, upper level ridging redevelops over the West Coast this weekend into next week. Rain lovers should not fully despair yet as models do signal some potential for rain to return late January/early February. The ECMWF shows some potential for light rain in early February with deep upper level troughing pushing into the West Coast. Models have consistently showed something developing late January/early February but the timing continues to be pushed back. The timing of the return of rain will become more clear as we get closer in time to late January/early February.

While we aren't expecting any rain with this upper level trough, it will bring in cooler air amd a return of more seasonal temperatures. High temperatures remain warm on Tuesday with highs in the mid 60s to low 70s (approximately 5 to 10 degrees above normal). Temperatures cool into the upper 50s to mid 60s Wednesday into the weekend as the ridge breaks down and cooler air arrives with the upper level trough. As the ridge rebuilds over the weekend, temperatures may warm by a few degrees but overall remain seasonal in the low to mid 60s. Winds shift onshore mid to late week as the upper level low moves down the coastline but they will shift offshore again by the weekend as the ridge rebuilds. Localized dense fog continues nightly across the interior valleys through the weekend with the potential for more fog to become more widespread across the interior valleys starting Thursday night.

AVIATION

(12Z TAFS) Issued at 315 AM PST Mon Jan 19 2026

Persistence forecast. High confidence in intermittent FG/BR invof KSTS and KAPC. Tule fog along the Delta will likely impact interior East Bay terminals such as KCCR and KC83. Otherwise VFR prevails through the period for all other terminals. Winds remain light and variable.

Vicinity of SFO...VFR. Winds light and variable.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Winds light and variable. SE drainage flow out of the Salinas Valley during the overnight and morning hours.

MARINE

(Today through Saturday) Issued at 315 AM PST Mon Jan 19 2026

Light to gentle breezes continue across the waters this week. Slight increase in winds over the outer waters by late week as the large scale weather pattern begins to shift. Moderate period northwesterly swell enters the waters mid week, peaking Tuesday night into Wednesday morning.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...None.