textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1222 PM PDT Tue Apr 28 2026

- Overnight and early morning stratus returns to the forecast

- Warming and drying trend continues into the late week for areas away from the coast

- Cooler conditions return this weekend with a chance of drizzle and/or light rain into early next week

SHORT TERM

Issued at 1222 PM PDT Tue Apr 28 2026 (This evening through Wednesday)

Temperatures this afternoon will warm into the upper 50s to mid 60s near the coast and the interior reaching into the mid 60s to lower 70s under mostly sunny sky conditions. These temperatures are slightly below seasonal averages, generally up to 5 deg F cooler and up to 15 deg F cooler in the higher terrain. This is as a short-wave trough lingers over the Bay Area and northern Central Coast.

Expecting low clouds to return to the coast and locally inland into the coastal adjacent valleys overnight tonight and more so into Wednesday morning. There is a greater probability of this to occur as the marine layer is forecast to deepen overnight to around 1,000 feet.

On Wednesday, as low clouds gradually retreat to the coast, temperatures rebound to near or slightly above (up to 5 deg F) seasonal averages. However, cooler temperatures will persist in the higher elevations. This is as high pressure begins to build eastward from the eastern Pacific.

LONG TERM

Issued at 1222 PM PDT Tue Apr 28 2026 (Wednesday night through next Monday)

The warming trend will continue into late week with interior temperatures up to 10 deg F above normal by Friday as the aforementioned ridge builds overhead. Friday is when we have the greatest probability of reaching or exceeding 85 deg F across the interior, with the warmest being across the interior Central Coast (greater than 50%). However, the marine layer will remain in place and keep temperatures cooler near the coast. This is as the ebb and flow of late evening and overnight stratus returns to the coast and coastal adjacent valleys each day.

A slight cooling trend is forecast to return on Saturday as a mid/upper level low drops southward out of the Gulf of Alaska. This low pressure system will eventually become a cut-off low with high pressure building across British Columbia late in the upcoming weekend setting up a Rex block. This would bring drizzle and/or light rain to the coastal waters Saturday night and into Sunday. Then, as the mid/upper level low shifts inland Monday and Tuesday, it will bring increasing chances for drizzle and/or light rain to the Bay Area and Central Coast. Rainfall amounts from this system are expected to remain light, however they will make for wet roadways across the region.

AVIATION

(18Z TAFS) Issued at 1015 AM PDT Tue Apr 28 2026

The morning low clouds were much more scattered than I thought they would be at this time yesterday. There is still enough instability in the lower atmosphere to stay well mixed. In fact, we are starting to see some fair weather cumulus clouds pop up over the southern hills as the surface temperatures warm and take advantage of this instability. That being said, these midday clouds are not expected to bring significant impacts to the TAF sites, and there is high confidence in widespread VMC through through day. Clouds will start to roll in again overnight, but the coverage will again be spotty. High resolution models are pretty confident that the North Bay will stay clear of stratus, but that opens the possibility for radiation fog. The rest of the Bay Area has a decent chance for MVFR impacts as the marine layer gradually works to gain some structure overnight.

Vicinity of SFO...Relatively standard conditions today with clear skies and moderate onshore winds in the afternoon. The challenging part of the forecast is tomorrow morning. There is a 6 hour window between 12Z and 18Z where there is a 30-50% chance of MVFR impacts over the terminal. As we saw this morning (OAK developed a ceiling for 6 hours, while SFO only had it for 30 mins) the stratus deck doesn't look very healthy tomorrow and the forecast confidence is quite low.

SFO Bridge Approach...Similar to SFO

Monterey Bay Terminals...After a clear afternoon, the southern terminals have the best chance for both MVFR and IFR impacts overnight due to a more compressed boundary layer and better onshore flow. The high res models are fairly confident, but the persistence forecast is more optimistic, so it's not a slam dunk.

MARINE

(Today through Sunday) Issued at 818 AM PDT Tue Apr 28 2026

The gradient between high pressure over the Eastern Pacific and low pressure over California will build over the next few days, generating a strong NW breeze from Wednesday through Friday. These winds will build rough seas of 8-12 feet across exposed waters.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory from 3 PM Wednesday to 3 AM 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.

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

Small Craft Advisory from 3 PM Wednesday to 9 AM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM.