textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 256 PM PDT Wed May 20 2026

- Diurnally driven winds, with onshore winds during the afternoon and early evening.

- Warm and dry weather through Thursday leads to elevated fire weather concerns for the interior Bay Area and Central Coast.

- Above normal temperatures continue through midweek with seasonal temperatures returning by the upcoming weekend.

UPDATE

Issued at 805 PM PDT Wed May 20 2026

Interesting developments along the coastal Bay Area this afternoon, where an impulse of energy from the Pacific Northwest, visible as a band of higher clouds descending into the North Bay, and perhaps a coastal eddy were able to scour out the stratus deck along the coast north of Santa Cruz. Will monitor the stratus development overnight as the differing forces interact over the region. Forecast remains on track.

DialH

SHORT TERM

Issued at 256 PM PDT Wed May 20 2026 (This evening through Thursday)

A deeper marine layer, ~750 ft in depth, and stratus has resulted in cooler conditions near the coast so far this afternoon. Temperatures there are in the upper 50s to mid 60s. However, inland areas are well on their way to the upper 80s to lower 90s. Breezy onshore winds are likely to increase this afternoon and peak early in the evening with gusts up to 30 mph before easing overnight. With low clouds hovering near and along the coast, expecting a greater potential for stratus to spread inland through the Golden Gate and into the Salinas Valley tonight and into Thursday morning.

For Thursday afternoon, expecting little change compared to today with mostly sunny sky conditions across the interior. The higher elevations above 1000 feet will remain critically dry (10-20%) with poor overnight (less than 30% in spots) humidity recoveries.

LONG TERM

Issued at 256 PM PDT Wed May 20 2026 (Thursday night through next Tuesday)

Temperatures on Friday will heavily depend on how deep the marine layer becomes as the Bay Area and Central Coast remains between the high pressure to the west and troughing to the east. The stronger the marine layer, the less time there is for daytime heating (especially where the stratus hangs around for much of the day). Temperatures gradually cool over the weekend as troughing develops to the north.

Then, cooler and potentially unsettled weather returns for early next week as the aforementioned trough drops southward across the West Coast. As such, the 6-10 Day Temperature Outlook from the CPC indicates temperatures leaning below average with the same outlook for precipitation leaning above. Again, above average for this time of year may bring either drizzle and/or very light rain to the region as we go deeper into our "dry season". All that said, please keep up to date with the latest forecast information over the next few days.

AVIATION

(06Z TAFS) Issued at 926 PM PDT Wed May 20 2026

Currently a mixed bag of IFR-VFR at the terminals. Moderate to high confidence on IFR conditions at HAF, MRY, and SNS with VFR elsewhere tonight. Relatively lower confidence for HAF than the Monterey Bay terminals as stratus has been wiped out north of the Otter Eddy in Monterey Bay. If stratus does redevelop, it'll likely be around 12Z. Diurnal winds will prevail.

Vicinity of SFO...Currently VFR with northwesterly flow. High confidence in VFR and diurnal winds prevailing through the TAF period. FEW/SCT IFR clouds will be possible on the north side of the terminal if stratus sneaks through the Golden Gate Gap.

SFO Bridge Approach...The San Mateo Bridge Approach has a lower probability of IFR conditions.

Monterey Bay Terminals...Currently VFR and calm at MRY and IFR with northwesterly flow at SNS. Moderate to high confidence on IFR conditions through the night; however, this Otter Eddy could be a case where SNS continues to get fed IFR stratus while MRY remains just on the periphery. VFR is expected by late morning with IFR stratus sticking close to the coast during the day.

MARINE

(Tonight through next Monday) Issued at 441 PM PDT Wed May 20 2026

Hazardous conditions for small craft will continue through Thursday for the northern outers due to rough seas and strong northerly breezes. Elsewhere, moderate northwesterly breezes and moderate seas will prevail. Conditions improve into the weekend as seas and northwesterly breezes become moderate.

MTR WATCHES/WARNINGS/ADVISORIES

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