textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1147 PM PDT Wed Aug 19 2026

- Gradual cooling trend today into the beginning of the weekend

- Elevations above about 1000 feet will have warm temperatures and RH values in the teens early this morning into the afternoon

SHORT TERM

Issued at 1147 PM PDT Wed Aug 19 2026 (Today and tonight)

We've been in the middle of a subtle back and forth between troughing over the EPAC and ridging over the desert southwest the past week or so. The net result has been only small changes in our day-to-day ambient weather conditions. However, the influence of troughing nudging back to the east toward our coastline today, will result in the beginning of gradual cooling, that will continue into the weekend. Improved lower boundary layer onshore flow will help bring temperatures around 5-10 degrees below normal away from the coast, while still remaining above normal in southern Monterey County. The depth of the marine layer influence will increase as well today helping to further support cooler temperatures. The more mild overnights we've been seeing will moderate closer to normal too, leading to stratus pushing farther inland after sunset into early Friday morning.

LONG TERM

Issued at 1147 PM PDT Wed Aug 19 2026 (Friday through Wednesday)

The gradual cooling trend into the beginning of the weekend levels off by Sunday into the beginning of next week with only minor, likely unnoticeable changes through the remainder of the extended forecast. The strong dome of high pressure over the desert southwest shows hints of shifting back to the west by the end of next week, which would bring warmer temperatures, however there is still no signal for a significant pattern change. Tropical wave activity is still expected to steer well south and west of our area with little to no impacts on our forecast attm.

AVIATION

(06Z TAFS) Issued at 935 PM PDT Wed Aug 19 2026

Currently LIFR-VFR. Persistence forecast on tap with moderate to high confidence in IFR ceilings returning to all terminals tonight. Further deterioration to LIFR is expected at coastal terminals and STS. If the marine layer undergoes compression, conditions will further deteriorate with less inland extent expected. VFR is expected by the afternoon (except for HAF) with IFR stratus sticking close to the coast. Diurnal winds will prevail.

Vicinity of SFO...Currently VFR with westerly flow. High confidence in an IFR ceiling returning tonight with VFR by late-morning. Diurnal winds will prevail.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently IFR with westerly flow at MRY and IFR with northwesterly flow at SNS. High confidence in conditions deteriorating to LIFR. At least a brief period of VFR is expected by tomorrow afternoon. Diurnal winds will prevail.

MARINE

(Tonight through next Tuesday) Issued at 935 PM PDT Wed Aug 19 2026

Moderate to fresh northwesterly breezes will prevail through Friday, increasing to become fresh to strong over the weekend. Hazardous conditions for small craft are expected across the outer waters and along the coastal jet regions into Friday. Rough seas in the outer waters will slowly abate with moderate seas prevailing by Friday.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory until 3 AM PDT Friday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory from 3 PM to 9 PM PDT Thursday for Pigeon Pt to Pt Pinos 0-10 nm.