textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1253 PM PDT Fri Aug 28 2026

- Slight chance of rain showers through this afternoon with thunderstorm chances focused on the Central Coast, tapering off by this evening

- Cooling trend continues into early next week

SHORT TERM

Issued at 1253 PM PDT Fri Aug 28 2026 (This evening through Saturday night)

Temperatures are struggling to warm to their forecasted maximum values this afternoon. This is as abundant mid-to-high level cloud cover from remnant moisture from former Tropical Storm Iselle moves over the region. However, we are seeing via satellite that breaks in this cloud cover are appearing off of the Central Coast. This may result in enough heating to destabilize conditions across this region. As such, we are keeping the Red Flag Warning in effect through 3 PM this afternoon given the dry lightning potential.

The mid-to-upper level moisture is forecast to shift eastward into the Sierra Nevada as the trough off of the Pacific Northwest coast deepens. Thus, rain showers and the potential for thunderstorms greatly diminishes after sunset. However, the aforementioned trough will result in a deepening of the marine layer tonight and into the upcoming weekend. Therefore, an increased probability of stratus near the coast and into the adjacent valleys overnight tonight.

Slightly warmer temperatures are expected on Saturday as low clouds that do develop overnight retreat back to the coastline by tomorrow afternoon and give way to mostly sunny skies across the interior.

LONG TERM

Issued at 1253 PM PDT Fri Aug 28 2026 (Sunday through next Thursday)

A reinforcing trough deepens off of the Pacific Northwest coast by Monday, allowing afternoon temperatures to be some 5 to 15 degrees below seasonal averages. Beyond Monday and Tuesday, the latest guidance indicates troughing off of the West Coast will be stronger than previous anticipated. Therefore, less likely to see tropical moisture from the Eastern Pacific to advect northward. However, confidence remains low at this time. Be sure to keep up to date with the latest forecast information from a trusted and reliable source.

AVIATION

(06Z TAFS) Issued at 841 PM PDT Fri Aug 28 2026

It's VFR except for areas of stratus /MVFR-IFR/ along the immediate coastline. The mid-latitude wind flow pattern is returning with drying air tonight and Saturday. The GFS shows precipitable water quickly lowering tonight and Saturday, near the 10th percentile on Oakland upper air soundings for late August. With decreasing water vapor aloft this will result in radiative cooling and with lingering boundary layer moisture it's likely to continue cooling to saturation resulting in additional fog and stratus /IFR-LIFR/. Diurnal surface warming will mix out fog and stratus improving conditions to MVFR-VFR by late Saturday morning and afternoon. Stratus and fog /MVFR-IFR/ redevelop Saturday night.

Vicinity of SFO...VFR until tempo stratus /MVFR/ 06z-08z tonight, then stratus /MVFR/ prevailing tonight to 18z Saturday morning. Thereafter VFR is forecast Saturday afternoon to mid evening. West wind near 15 knots tonight decreasing to 8 to 10 knots late tonight and Saturday morning. West wind increasing to 15 to 25 knots Saturday afternoon and evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR then stratus /IFR-LIFR/ redevelops tonight and Saturday morning. Surface warming will mix out stratus by late Saturday morning and afternoon. Stratus /IFR/ redevelops Saturday night. West to northwest winds 5 to 15 knots.

MARINE

(Tonight through next Thursday) Issued at 834 PM PDT Fri Aug 28 2026

Fresh northwest breezes with occasional near gale force gusts continue through the weekend as well as a long period southerly swell. The long period southerly swell peaks on Saturday around 17 to 18 seconds and gradually diminishes by Sunday night. Wind driven seas briefly build to rough Saturday afternoon into Sunday and gradually subside to moderate through next week.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory from 9 AM Saturday to 3 AM PDT Sunday for Mry Bay.

Small Craft Advisory until 9 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory until 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm.