textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1215 AM PDT Wed May 6 2026

- Warmer and drier conditions mid to late week

- Well above normal for May with warm to hot temperatures this weekend and early next week

SHORT TERM

Issued at 1235 AM PDT Wed May 6 2026 (Today and tonight)

Cool temperatures and cloud cover left over from the recent 500 mb low continue to linger. Tuesday evening's Oakland upper air sounding showed ~ 25th percentile temperatures at 925 mb (2500 feet) and 850 mb (5000 feet) for early May, just below a newly developed temperature inversion aloft. The temperature inversion is an early sign of newly warming air aloft with 500 mb high pressure beginning to advance in across the forecast area. With clearing by late morning and afternoon, daytime highs will climb to the 60s coastside and bayside to the 70s to 80 well inland. In areas that received recent rainfall, lingering surface to lower level water vapor availability combining with peak daytime surface heating may cause mainly small cumulus clouds to develop today as well.

For tonight, post sunset cooling will diminish any small cumulus clouds while lower level temperatures steadily warm, strengthening the lower level temperature inversion. Coastal stratus clouds return tonight, capped underneath the lower level temperature inversion. The SFO-SAC pressure gradient remains onshore through today, near 3 mb by late afternoon then decreases to 1 mb by early Thursday. Onshore winds will usher stratus inland tonight. Low temperatures tonight in the 50s and 40s.

LONG TERM

Issued at 1235 AM PDT Wed May 6 2026 (Thursday through Tuesday)

A 500 mb high pressure ridge moves in from the west and northwest during this time, the ridge flanked on each side by strengthening troughs assisting in dynamic strengthening (meridional north-south wave strengthening). Lower to mid level thermal ridging will move in across the forecast area as well. 500 mb heights will increase to above normal Thursday through Tuesday, peaking over the weekend to early next week. By Sunday, Monday and Tuesday recent ECMWF forecasts show 850 mb temperatures warming up to 20 to 23 Celsius which is right around the max moving average on Oakland soundings for the time of year. This means surface temperatures will become warm to hot, daytime highs in the 80s to 90s away from any marine influence. Early next week a few spots in the southern interior may also reach 100F. We may also get close to a few record highs at the long term stations. If planning to be outdoors please keep in mind that moderate HeatRisk will be developing for inland areas Sunday, Monday and Tuesday.

There have been recent positive anomalies observed in the subtropical jet stream winds (stronger than usual) entering the southwestern states. Global models, particularly the GFS shows strength maintaining in both the polar jet stream and subtropical jet stream winds crossing the Pacific during this forecast period. The larger scale pattern may nudge eastward the aforementioned high pressure system a little quicker to our forecast area. This means that late week including Saturday for example may warm up a little faster than currently forecast. Something to keep in mind. Please stay tuned to the latest updates.

AVIATION

(06Z TAFS) Issued at 943 PM PDT Tue May 5 2026

Elevated stratus remains locked in over the region, but there a "sloshy" nature to it as the edges ebb and flow. Not a standard stratus deck. As such, conf is lower. Through the first few hours of the TAF will keep it elevated, but then enough cooling overnight should lower CIGs to MVFR most areas. MVFR through mid- late Wed AM and then VFR (except HAF). Early return tomorrow evening for places like MRY.

Vicinity of SFO...VFR with SFO in a bit of a clouds "hole" at the moment. Expect this to fill in with MVFR developing and then last through 18-20Z Wed.

SFO Bridge Approach...Solid stratus deck 2500-4000ft.

Monterey Bay Terminals...Elevated stratus lowering to MVFR. VFR re-developing by early Wed afternoon.

MARINE

(Tonight through next Monday) Issued at 925 PM PDT Tue May 5 2026

High pressure over the eastern Pacific will maintain gentle to moderate northerly breezes over the coastal waters through early Thursday. Fresh to strong northerly breezes develop Thursday afternoon through the weekend leading to locally hazardous conditions and building seas with steep fresh swell.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...None.