textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 253 PM PDT Thu Aug 20 2026

- Seasonable to seasonably cool temperatures through early next week

- Elevations above about 1000 feet will remain warm and dry

SHORT TERM

Issued at 253 PM PDT Thu Aug 20 2026 (This evening through Friday night)

The marine layer retreated to the coast as expected and high clouds continue to stream overhead. Expect these conditions to hold for a few more hours, before the marine layer and associated stratus begin to creep inland. Models suggest the marine layer is suppose to be around 1000ft tonight, which should limit its expansion into the South and East Bay valleys. Will need to keep an eye on its arrival and the actual footage as the picture from space has indicated a slightly deeper marine layer the past few mornings. Nonetheless, for those that do get the stratus, look for cloudy skies, coastal drizzle, and potentially patchy fog through the morning hours. Low clouds will either erode or retreat to the coast, while high clouds continue overhead. The cooling trend continues into tomorrow, with high temperatures being a few degrees lower than today.

LONG TERM

Issued at 253 PM PDT Thu Aug 20 2026 (Saturday through next Wednesday)

No major changes to the long term forecast. A stout upper level ridge will remain over the Desert Southwest while an upper low tracks into the PacNW and southwestern Canada. We'll likely be in some form of weak troughing to quasi zonal flow during this time period, with temperatures cooling through Saturday and then moderating for the rest of the forecast period. Drier air works its way into the upper levels across at least the North Bay, which might limit the stratus up there. Looking toweards the end of the period, the strong dome of high pressure tries to slighlty build towards us. High temperatures should increase by a few degrees in response to this.

AVIATION

(18Z TAFS) Issued at 1211 PM PDT Thu Aug 20 2026

Stratus has retreated to the coastline with most terminals in VFR and a parade of high clouds cruising overhead. HAF is the exception as they may have a brief scattering period this afternoon before developing IFR ceilings again. Typical onshore breeze pattern persists through the TAF period with an increase this afternoon. The marine layer returns this evening with a mixture of MVFR, IFR, and LIFR ceilings impacting coastal sites as early as sunset and inland sites around midnight. Medium confidence on the ceiling forecasts for LVK and SJC as the marine layer is expected to compress slightly overnight which may impact ceiling heights as well as coverage.

Vicinity of SFO...Onshore winds increase through the day with VFR conditions prevailing during most of the afternoon. Borderline MVFR-IFR ceilings roll in around sunset tonight and persist until late morning Friday. Westerly winds decrease through the overnight hours and increase as stratus clears tomorrow morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the afternoon with west to northwest winds increasing to around 10 kt. IFR ceilings impact both SNS and MRY around sunset time and drop to LIFR overnight as the marine layer compresses. This compression will impact visibility due to mist/drizzle. Conditions will gradually improve by late Friday morning. Medium confidence on exact timing of LIFR conditions.

MARINE

(Tonight through next Tuesday) Issued at 253 PM PDT Thu Aug 20 2026

Northwest moderate to fresh breezes persists into the weekend with higher winds expected near the coastal jet regions of Point Reyes and Point Sur. Occasional strong gusts are possible across the outer waters and coastal jet areas through Saturday. Wind driven seas remain slight at the coastline and quickly build to moderate across the outer waters through the weekend.

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.

Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt to Pt Pinos 0-10 nm.

Small Craft Advisory from 11 AM to 9 PM PDT Friday for Pigeon Pt to Pt Pinos 0-10 nm.

Small Craft Advisory until 3 AM PDT Saturday for Pt Pinos to Pt Piedras Blancas 0-10 nm.