textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1205 AM PDT Sun May 10 2026

- Warming and drying trend will continue through early in the week with afternoon temperatures peaking on Monday

- Moderate risk for heat-related illnesses for sensitive populations across the interior on Monday

- Gradual cooling trend and potential unsettled weather from midweek through late week

SHORT TERM

Issued at 1215 AM PDT Sun May 10 2026 (Today through Monday)

Let's step back and take a look at the interesting longwave pattern over the CONUS - ridge of high pressure covers CA which is bookended by deep troughs on either side with one near the Great Lakes and the other near Gulf of AK. The pattern will hold in the near term, but will shift with a pattern change on the horizon, literally. So what does this set up mean for the Bay Area? A ridge of high pressure in May usually brings dry and mild conditions and Sunday is no exception. However, it's the details that matter. Overnight satellite imagery shows solid stratus along the coast working its way inland. The marine layer will likely top out 900-1200 feet this morning and will be the spoiler for Max T potential. Would not be surprised one bit if the marine layer was able to squeeze out some drizzle along the coast. Model guidance has struggled the last few days regarding Max T and the marine layer influence...simply put the forecast was too warm. As such, trended temperatures downward from the NBM over inland valleys or areas that have a pronounced marine layer influence this afternoon. Went colder by 3-5 degs, but worried it wasn't under cut enough. That being said, do expect the marine layer clouds to erode back to the coast by this afternoon with inland sunshine and coastal clouds. Regardless, if you have outdoor activities to celebrate Mother's Day it will be pleasant with inland highs in the 70s and 80s and cooler at the coast in the 60s - bring a jacket. Could also be a tad breezy this afternoon with the temp difference from the coast to interior. Sfc pressure gradients remain onshore again, but are forecast to be weaker than Saturday where they peaked at 4.2 mb.

Sunday night through Monday - the center of the upper ridge begins to shift toward the Desert SW while the upstream trough deepens and inches toward the West Coast. Despite the shift, Monday is still on track to be the warmest day of the forecast. 850 mb temps peak at 20-22C. Mixing those temps to the surface under ideal conditions would bring toasty temps. However, we still have some onshore flow and lingering marine layer. As such, max temps will be tempered near the coast and bays, 60s to lower 80s. Far interior locations will be in the 90s leading to some Moderate HeatRisk.

LONG TERM

Issued at 1220 AM PDT Sun May 10 2026 (Monday night through next Saturday)

The change in the longwave pattern begins to unfold Monday night into Tuesday. The upper level ridge is being replaced by a robust and anomalously deep upper low for mid May. Temperatures begin to drop in response to lower 500 mb heights and cooler 850 mb temps, but still above normal.

By Wednesday near normal temperatures return thanks to the cut-off low over the region. Confidence fades on the details of the exact placement of the cut-off low...cluster analysis is split with some favoring more zonal flow and others farther south with a deeper low. Regardless of exact placement, it's clear that temps drop and at least some drizzle is likely. A few members even show light showers Wednesday afternoon/evening (tstorms to the N).

Zonal flow returns for the second half of the work week leading to rebounding temperatures and drier conditions.

MARINE

(Tonight through next Friday) Issued at 906 PM PDT Sat May 9 2026

Moderate seas and fresh to strong northwest breezes with occasional near gale force gusts will continue through most of Sunday. Locally gusty conditions are likely across the San Pablo and San Francisco Bays where terrain promotes wind funneling. Winds gradually ease starting late Sunday with a gentle to moderate northwesterly breeze expected early to mid week. Breezy conditions return to the inner waters late week and seas build mid to late week.

MARINE

(Tonight through next Friday) Issued at 906 PM PDT Sat May 9 2026

Moderate seas and fresh to strong northwest breezes with occasional near gale force gusts will continue through most of Sunday. Locally gusty conditions are likely across the San Pablo and San Francisco Bays where terrain promotes wind funneling. Winds gradually ease starting late Sunday with a gentle to moderate northwesterly breeze expected early to mid week. Breezy conditions return to the inner waters late week and seas build mid to late week.

MTR WATCHES/WARNINGS/ADVISORIES

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

Small Craft Advisory until 3 AM PDT Monday for Pt Arena to Pt Reyes 0-10 nm.

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

Small Craft Advisory until 9 AM PDT Monday for Pt Arena to Pt Reyes 10-60 NM.