textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1036 PM PDT Tue May 19 2026

- Diurnally driven winds, with onshore winds during the afternoon and early evening.

- Above normal temperatures continue through midweek with seasonal temperatures returning late week.

- Warm and dry weather through Thursday leads to elevated fire weather concerns for the interior Bay Area and Central Coast.

UPDATE

Issued at 940 AM PDT Wed May 20 2026

Temperatures in the lower elevations are up to 10 degrees cooler compared to this time yesterday. This is thanks to a deeper marine layer in place and lack of stronger offshore winds. Thus, maximum temperatures may be cooler than yesterday as a result. However, very dry conditions will persist in the higher terrain generally above 1,000 feet.

RGass

SHORT TERM

Issued at 1036 PM PDT Tue May 19 2026 (Tonight through Thursday)

Little change in the forecast as high pressure slowly creeps into Northern California today. Satellite imagery this evening shows high clouds sliding down the West Coast, with much of the Bay Area likely seeing some cirrus. With the current data, temperatures look to be on track; however, if we're not able to get radiational cooling, our temperatures for tonight might be low/cool. This would be because the clouds act as blanket, allowing less heat to escape at night. It'll be something to keep an eye on over the next few hours.

In terms of Wednesday, if you guessed, "No pattern change. Ha, this means another day of warmer weather", you'd be correct! A potential fly in the ointment is if the marine layer attempts to manifest around 500 feet. This might keep temperatures a few degrees cooler along the immediate coast, but elsewhere temperatures should be similar to Tuesday, perhaps a few degrees higher.

LONG TERM

Issued at 1036 PM PDT Tue May 19 2026 (Thursday night through next Tuesday)

No major changes to the extended forecast. Upper level troughing looks to keep hold over the western US, while the Pacific high pushes even more into northern California on Thursday. With the high being a bit more pronounced, another warm day will be on tap. After that, guidance has flow becoming quasi-zonal for a brief period before troughing returns on Friday. The marine layer looks to be around 500ft on Thursday, deepening to around 1000ft by Friday and then lasting through the weekend. With onshore flow, a deeper marine layer, and troughing through the weekend the NBM's temperatures are bit too warm. Opted to start trending towards slightly cooler temperatures given the ensembles and cluster analysis. But there is a chance ridging wins out and temperatures might warmer. Definitely something to keep an eye on over the next few days.

AVIATION

(12Z TAFS) Issued at 503 AM PDT Wed May 20 2026

VFR at the big three this morning and expect that to continue despite some stratus forming offshore. Guidance was a little too aggressive in bringing in stratus elsewhere and thus have cut back on stratus this morning. HAF and SNS are experiencing some hz/br drop the flight CAT. VFR this afternoon gusty onshore flow. Gusts 15-20kt seems reasonable. For tonight, marine layer currently off the coast will move locally inland with highest conf for HAF and MRY/SNS.

Vicinity of SFO...VFR. NW winds ramp up this afternoon with gusts to 20kt.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MRY is VFR, but enough low level moisture is at SNS to have occasional br/hz. Much higher conf for stratus intrusion tonight into Wednesday.

MARINE

(Today through Monday) Issued at 940 AM PDT Wed May 20 2026

A weak frontal boundary to the north will maintain fresh to strong northerly breezes and rough seas over the outer waters north of Pigeon Point through early Thursday. Elsewhere, moderate to fresh northerly breezes and moderate seas will prevail. Conditions improve into the weekend as seas and northwesterly breezes become moderate.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory until 3 PM PDT Thursday for Pt Arena to Pt Reyes 10-60 NM.