textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 147 PM PDT Wed Aug 19 2026

- Compressed marine layer today, increases Thursday into the weekend

- A gradual cooling kicks off Thursday and continues into the weekend

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

SHORT TERM

Issued at 147 PM PDT Wed Aug 19 2026 (This evening through Thursday night)

Little change to the forecast as we shift from quasi-ridging to more zonal flow in the upper levels over the next day. An upper level low will slowly advance towards the West Coast, nudging the Desert Southwest high slightly eastward. This will allow a cooling tend to start on Thursday, in addition to the marine layer deepening and onshore flow increasing. The marine layer should get to 1000-1200ft by Thursday morning, leading to another night with wide spread stratus, patchy fog, and patchy coastal drizzle. Elevations above the marine layer, wont' be as lucky and will continue to be warm and dry above it. Clouds begin to clear by early to mid morning, with the stratus retreating to the coast by late morning. High clouds look to return to the forecast tomorrow which should leave us with partly to mostly cloudy skies. High temperatures will likely be a couple of degrees cooler than Wednesday.

LONG TERM

Issued at 147 PM PDT Wed Aug 19 2026 (Friday through next Tuesday)

The upper level low continues to track towards the West Coast, with the trough elongating southwards and the shortwave or closed low moving towards the PacNW by Saturday. Troughing holds over the region through early next week, which will lead to temperatures being anywhere from 5 to 15 degrees below their seasonal normal. Stratus looks promising each night through at least Saturday morning, with the marine layer potentially compressing Saturday night into Sunday morning. Models suggest it could deepen again Sunday night into Monday morning, which may lead to more widespread stratus.

AVIATION

(00Z TAFS) Issued at 426 PM PDT Wed Aug 19 2026

Currently VFR with the exception of HAF which is IFR. Another persistence forecast on tap with little change in the pattern. As such, 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. Diurnal winds will prevail.

Vicinity of SFO...Currently MVFR due to haze with northwesterly flow. Moderate 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 VFR with westerly flow at MRY and VFR with northwesterly flow at SNS with IFR stratus lurking off the coast. High confidence in IFR conditions retuning early this evening with further deterioration to LIFR expected. VFR is expected by tomorrow afternoon. Diurnal winds will prevail.

MARINE

(Tonight through next Monday) Issued at 426 PM PDT Wed Aug 19 2026

Moderate to fresh northwesterly breezes with strong gusts across the northern outer waters and along the coastal jet regions will bring hazardous conditions for small craft periodically through the weekend. Breezy fresh winds are expected across the San Pablo Bay and the San Francisco Bay with locally stronger gusts possible where terrain promotes wind funneling. Rough seas in the outer waters will subside Thursday 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.