textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1004 PM PDT Tue Apr 21 2026

- Cool conditions Wednesday with lingering showers through the day

- Seasonal temperatures and dry conditions arrive Thursday

- Monitoring potential rain and drizzle this weekend into the early part of next week

SHORT TERM

Issued at 129 PM PDT Wed Apr 22 2026 (This afternoon through Thursday)

While not as active as 24 hours ago we still have KMUX is precip mode. Current radar loop this afternoon still shows widely scattered showers around the Bay Area and Central Coast. Afternoon visible satellite shows popcorn city with an extensive CU field blanketing the region. Why the showers? The main storm system from yesterday has exited to the east. On the back side of this system are trialing embedded vort maxes/shortwaves. Those features in conjunction with lingering moisture, daytime heating, and weak instability has led to the showers. That being said, not enough lift or vertically developed storms to generate thunderstorms.

This evening and tonight, once the sun sets expect shower activity to quickly diminish and CU field thin. One potential impact tonight will be some developing low stratus and fog. Clearing skies and decreasing winds will allow for some fog development over the inland valleys.

Thursday: Dry, warmer, and more sunshine due to weak upper level ridging. Max temps will be in the 60s to mid 70s, which is closer to seasonal averages.

LONG TERM

Issued at 129 PM PDT Wed Apr 22 2026 (Thursday night through next Tuesday)

A few days ago the longer term forecast didn't look to interesting from a weather impact standpoint, but a trend has emerged over the last 24-36 hrs showing active weather will continue. First and foremost it will not be as dynamic as the system that we just had. However, a previously dry-ish weekend is now trending "wetter". What's the trend? Subtle ridging aloft is now looking more trough-y with an upper low over the region. The longwave pattern keeps kicking the upper low from yesterday eastward. In its wake subtle ridging is now being replaced by another upstream trough. It now appears enough jet dynamics aloft emerge to shift the broad upper trough to a more pronounced upper low late Thursday into Friday. Heights begin to fall by Friday lowering temps and ushering in more clouds. By Saturday morning an upper low develops off the Central Coast. As such, light drizzle/light rain will return. This set up will persist through early Sunday with drizzle/light rain. Not expecting much accumulation, just some wet ground, clouds, and cooler temps. Another upper low develop early next week bring additional rain chances on Tuesday into Wednesday. Again, not a big storm, just additional moisture.

AVIATION

(18Z TAFS) Issued at 1136 AM PDT Wed Apr 22 2026

The last band of rain is passing through the region, with drier air working in behind it. VCSH and -SHRA are possible for the next couple of hours for most sites, with precip turning off later this afternoon. Satellite shows a mess of clouds, slowly breaking apart leaving us with a smattering of MVFR cigs at terminals or they're flirting with them. Clearing skies should continue and bring VFR by the late afternoon and evening. The question for tonight will be do clear skies and light wind lead to patchy fog. Most models say no, but it will be something we need to monitor for the next few TAF cycles.

Vicinity of SFO...The challenge for the next few hours will be the east to southeast winds and when they'll shift to the southwest. Most model guidance has not captured the current wind pattern at SFO and around the region, with MOS guidance and the some NBM guidance showing it occuring between 20-21Z. Winds should eventually become onshore this afternoon before going light again overnight. Tomorrow onshore winds pick up mid to late morning, with the with winds increasing to around 15kt around or after 21Z.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Showers will linger around the Monterey Bay this afternoon with conditions drying out by the evening. VFR cigs are generally expected through this period unless a stronger shower moves through which could bring MVFR cigs.

MARINE

(Today through Monday) Issued at 1136 AM PDT Wed Apr 22 2026

Scattered light showers continue to drift to the southeast through the southern waters this morning and will exit the region this afternoon. A moderate northwest breeze will develop this afternoon, then increase on Thursday to a fresh northwest breeze. Wind and seas will begin to gradually subside on Friday, continuing into the weekend.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory from 3 PM to 9 PM PDT Thursday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0- 10 nm.

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

Small Craft Advisory from 3 PM Thursday to 3 AM PDT Friday for Pigeon Pt to Pt Pinos 10-60 NM.