textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1104 PM PDT Mon Apr 6 2026

- Above normal temperatures and dry conditions through Wednesday

- Unsettled weather returns Thursday with below normal temperatures and beneficial rainfall

- Isolated to scattered thunderstorms Thursday and Friday

SHORT TERM

Issued at 1104 PM PDT Mon Apr 6 2026 (Tonight through Wednesday night)

Upper-level shortwave ridging will dominate our weather through Wednesday. This will result in above normal temperatures and dry conditions. Fortunately, a decent marine layer of about 1,500 feet is expected during this time which will keep conditions cooler at the coast and the natural air conditioning on.

LONG TERM

Issued at 1104 PM PDT Mon Apr 6 2026 (Thursday through next Monday)

A vertically stacked surface low in the Eastern Pacific Ocean near 37 N, -140 W will kickoff our pattern change. As it encroaches our marine zones on Thursday, it'll increase PWAT values to near the 90th percentile (0.79 inches for 12Z April 9th). The RRFS sounding profile can be characterized by low CAPE, conditionally unstable lapse rates, and low shear. As such, a slight (up to 15%) chance for thunderstorms is being advertised for Thursday. Thunderstorm chances increase Friday (15%-25%) as the surface low moves inland. Thunderstorm impacts include lightning, locally heavy rainfall, erratic/gusty winds, and small hail. There still remains uncertainty in the exact location and timing of the cutoff low as this feature is notoriously difficult to forecast due to their independence from the Polar Jet Stream. As such, rainfall totals on Thursday and Friday will be heavily dependent upon where rain showers/thunderstorms develop. Upper-level longwave troughing develops off the West Coast Saturday as an upstream trough digs south and connects with the cutoff low with the help of a dip in the Polar Jet Stream. As a result, widespread beneficial rainfall, below normal temperatures, and strong onshore winds are expected Saturday into Sunday with a cold frontal passage. Gusts up to 40 mph can be expected in the higher terrain and through west-east oriented gaps and passes. When all is said and done, rainfall on the order of 0.25"-0.75" inches is expected with locally higher totals of 1.00"- 1.50" inches in the coastal ranges.

AVIATION

(06Z TAFS) Issued at 955 PM PDT Mon Apr 6 2026

MVFR-IFR stratus has developed at the coast and moving inland with impacts expected to persist through the night. Some lingering moderate onshore winds will diminish through the next couple of hours. The stratus deck retreats to the immediate coast on Tuesday morning, with breezy onshore winds returning in the afternoon. Some high resolution models suggest that HAF might scatter out sometime on Tuesday afternoon, but this is a low confidence forecast and have opted to keep the terminal socked in for now. Towards Tuesday night, not seeing an impressive signal for inland stratus development with winds staying breezier aloft into the end of the 24-hour TAF period, with some model output persisting near SFO, OAK and the Monterey Bay terminals. This might make for bumpy takeoffs and landings in the interior terminals, although LLWS concerns remain below TAF criteria.

Vicinity of SFO... Lingering moderate westerly winds will diminish through the next couple of hours. MVFR-IFR stratus persists through the night and will dissipate Tuesday morning around 18-20Z, with breezy west-northwest winds in the afternoon. Low confidence in stratus returning Tuesday night with breezier winds persisting aloft.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... MVFR-IFR ceilings persist through the night and dissipate late Tuesday morning. Gentle northwest winds overnight will increase and become moderate Tuesday afternoon. Lower confidence for stratus development Tuesday night, but some model output places stratus over the terminals before the end of the TAF period.

MARINE

(Tonight through next Sunday) Issued at 955 PM PDT Mon Apr 6 2026

High pressure off the California coast will maintain light to moderate breezes across the coastal waters through the week, with localized fresh breezes off the Big Sur Coast through Tuesday. Unsettled weather returns mid to late week, bringing light showers, a slight chance of thunderstorms, and moderate seas. Winds increase next weekend with a fresh breeze expected over portions of the coastal waters.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory until 9 PM PDT Tuesday for Pt Pinos to Pt Piedras Blancas 0-10 nm.