textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1205 AM PDT Fri Apr 3 2026

- Moderate to strong offshore flow Friday

- Warm weather returns through the weekend

- Cooler weather and rain chances next week

SHORT TERM

Issued at 1205 AM PDT Fri Apr 3 2026 (Today and tonight)

Post-frontal high pressure brought strong onshore winds Thursday. This feature has moved inland over Oregon, and will continue towards northern Nevada over the next 12 hours. As it does, the gradient between the surface high and a trough along the coast of California will strengthen. The SFO-WMC gradient was +14 mb last night, and is dropping sharply. It's currently around -4.5 mb and will bottom out around -10 mb later today. This gradient will support moderate to strong offshore winds through midday Friday before the high starts to weaken and the offshore gradient gradually relaxes through the weekend. The strongest winds should be over the Vaca Mountains in Napa County. Stable conditions in the lower atmosphere will encourage mountain wave activity that will allow strong gusts to reach the valley through the morning hours.

Outside of the burst of offshore winds, a warming trend is the biggest story in the short term forecast. Now that the cold front has moved well inland, the pattern is flipping back to warm and dry. At 500 mb, a NW to SE oriented ridge will build over the next 48 hours. This upper level high will increase temperatures through large scale subsidence and clear skies. The 850 mb temperature averaged 2.8 C Thursday, which is between the 10th and 25th percentile for this time of year. That metric will shoot up to around 13-14 C by Friday afternoon, or roughly the 75th percentile. Inland temperatures will respond by reaching the mid to upper 70s this afternoon. The coast will get in on the warmer temperatures as well, thanks to the offshore winds.

LONG TERM

Issued at 1205 AM PDT Fri Apr 3 2026 (Saturday through Thursday)

We will pick up some high clouds on Saturday as an upper level plume of moisture rides over the ridge. Otherwise the warming trend will continue through the weekend as the 850 temperatures continue to climb. Inland temperatures will reach the mid 80s on Saturday and Sunday. That about 15 degrees above normal, and it's possible we could set a daily record or two.

The return of weak onshore flow Sunday will likely bring the immediate coast back into the low to mid 60s. There is a chance for a southerly surge on Sunday as well. This can happen when the large scale E-W pressure gradient becomes weakly offshore and the afternoon sea breeze butts up against the coastal mountains. If the atmosphere is stable, the air can't make it over the mountains and has to either go north or south parallel to the coast. The PGE-WRF shows a southerly surge developing Sunday morning and reaching San Francisco by midday. Southerly surges are hard to predict though, so it could be delayed until Monday or not happen at all. There is much higher confidence that the more typical marine layer will return Monday as stronger NW winds return to the coastal waters. These onshore winds will also cool inland areas back into the 70s Mon-Tue.

By mid-week ensemble clusters all agree the pattern will shift back to a troughing regime. This pattern will very likely bring a cold front across the cwa Wednesday, bringing a chance for precipitation. The ECMWF ensemble mean is generally between 1/10 and 1/4 inch of rain, with a 90% chance it's will stay below 1". That's firmly in the beneficial category, and there are no significant impacts expected. After the rain chance wane Thursday, seasonal temperatures continue through late week.

AVIATION

(06Z TAFS) Issued at 950 PM PDT Thu Apr 2 2026

High confidence of VFR through the TAF period with possible high clouds developing after midnight. Moderate northwest winds will diminish through the next couple of hours, with LLWS concerns developing after midnight in the interior valleys as surface winds decouple from winds aloft. At APC, high resolution models depict some mountain wave energy making it to the valley floor, resulting in gusts as high as 18 kt between 12-18Z. Considered keeping sustained wind speeds low to maintain the LLWS group within the forecast, but opted to prioritize reflecting increased wind speeds at the surface. For Friday, interior regions will see breezy north to northeast winds, especially in the morning hours, with the potential for strong gusts in favored locations. Elsewhere, a gentle to moderate northwest flow develops in the afternoon.

Vicinity of SFO... High confidence of VFR through the TAF period with possible high clouds overnight through Friday. Moderate and west winds persist through the late evening hours, with light winds turning offshore overnight before northwesterly breezes return late Friday afternoon, diminishing in the evening.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... High confidence of VFR through the TAF period with possible high clouds overnight through Friday. Light drainage winds will persist through Friday morning. At MRY, gentle winds will gradually turn from the northeast to the northwest through the late morning and afternoon hours on Friday, with SNS seeing a resumption of the northwest flow late Friday afternoon. Winds become light again late Friday evening.

MARINE

(Tonight through next Wednesday) Issued at 950 PM PDT Thu Apr 2 2026

Fresh to strong breezes persist over the coastal waters through the night into Friday, resulting in hazardous conditions for small craft. Northerly breezes diminish and seas abate by the weekend, with slight to moderate seas through the middle of the next week.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory until 3 AM PDT early this morning for Mry Bay-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 until 3 AM PDT Saturday for Pt Arena to Pt Reyes 10-60 NM.

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