textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1242 PM PDT Tue May 26 2026

- Cooler, unsettled weather conditions continue today and Thursday

- Warming and drying trend Friday and beyond

SHORT TERM

Issued at 1151 PM PDT Tue May 26 2026 (Today and tonight)

The center of the upper level disturbance responsible for the cool and unsettled weather yesterday and today will remain mostly stationary throughout the day. However it will weaken slightly over the course of the day with subtle H50 height increases from early this morning into this evening. The unusually cool air aloft, once again looking at H50 level, will be below the tenth percentile at around -21C to -22C, with H85 temps right around the tenth percentile at 5C to 6C. The cooler than normal temperatures aloft are transferring to the surface with low lying interior locations running 5F-10F degrees below normal for this time of year, and much cooler than normal at higher elevations, especially the highest peaks of Big Sur around 25F-30F degrees below normal.

As the upper low rotates overhead today, portions of the Bay Area, East Bay and South Bay will see periods of sunshine helping to produce marginal surface instability from around 100-300 J/Kg of CAPE this afternoon. Vertical wind profiles don't favor organized convection, with little to no 0-6km wind shear. Like yesterday in Napa County and Contra Costa County the best chances for rainfall amounts above 0.10" will be areas of terrain enhancement. The hills of eastern Contra Costa County and eastern Santa Clara County have approximately 20%-50% chance of exceeding 0.10" by late this afternoon. NBM thunderstorm chances are less than 10% area wide.

A portion of the upper level low will begin to retrograde back toward the coast tonight into early Thursday morning, increasing rain chances off shore that eventually begin to move onshore along the coast late tonight and farther inland through Thursday morning. Rain totals along the coast late tonight into early Thursday morning will be light, primarily less than a 0.10" from Santa Cruz south down the Big Sur coastline.

LONG TERM

Issued at 1151 PM PDT Tue May 26 2026 (Thursday through Tuesday)

Thursday will continue the unsettled pattern with a shift south across primarily the South Bay and Central Coast as the upper low begins to shift inland to the southeast during the day Thursday. The clouds and cooler temperatures will linger during the day Thursday with only light rainfall amounts where rain does occur, with less than a 0.10" expected.

Progressive upper ridging behind the exiting low to the east on Friday gives way to zonal flow aloft on Saturday as temperatures begin to rebound back closer to normal by Sunday into the beginning of next week. While we do gradually warm up through the remainder of the extended forecast beginning Friday, a signal for troughing in the syntopic pattern continues beyond the current extended forecast that should help maintain more seasonal temperatures.

AVIATION

(12Z TAFS) Issued at 420 AM PDT Wed May 27 2026

Patches of MVFR ceilings have developed within the East and South Bays, in addition to extensive MVFR-IFR cloud cover across the coastal regions south of the Golden Gate and into the interior Central Coast. This cloud cover should clear throughout the morning, and the rest of the region remains VFR with some scattered low clouds through the evening when MVFR-IFR stratus develops for the coastal and mountain regions. Scattered showers will be possible this afternoon in the higher elevations, and then turn widespread tonight into Thursday morning as a low splits off in the North Bay, retrogrades offshore, and parallels the coast. The back side of this shower activity is only expected to widespread shower activity is only expected to begin across the North Bay close to the end of the TAF period. Light to gentle winds should continue through the morning, with a strong SFO-WMC gradient supporting onshore flow in the afternoon and evening, although gusts will top out around 20-25 knots at the terminals. Winds later this evening through the end of the TAF period may vary depending on the track and location of the offshore low.

Vicinity of SFO... Low confidence of an MVFR ceiling popping up at the terminal area this morning, but the bulk of the stratus deck should remain to the west of the San Bruno Gap. Breezy west winds will develop this afternoon and evening with gusts of 20-25 knots expected, before winds diminish and shift to the south and southeast overnight. Scattered showers will approach the terminal around 03- 06Z before more widespread activity arriving later tonight through Thursday morning.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... MVFR ceilings and scattered showers continue through the next several hours before low-end VFR conditions return for the day. Breezy west winds develop in the afternoon and evening with gusts to around 20 knots. Widespread showers accompanied by MVFR-IFR ceilings and a wind shift to the southeast are expected to approach the region late tonight into the early hours of Thursday morning.

MARINE

(Today through Monday) Issued at 420 AM PDT Wed May 27 2026

Fresh to strong northwest winds will gradually diminish across the inner waters through the day with occasional near gale to gale force gusts possible across the far outer waters into the afternoon. Rough seas continue with wave heights between 12 to 16 feet through Thursday, abating on Friday before stronger winds cause another round of building seas beginning next weekend.

MTR WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement until 9 AM PDT this morning for CAZ006- 505-509-529-530.

PZ...Small Craft Advisory until 9 AM PDT this morning for Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory until 3 PM PDT Thursday for Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory until 9 AM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM.