Issued at 737 AM PDT Wed May 6 2026
Extensive stratus coverage was observed across the Bay Area with patchy coverage in the Monterey Bay region and interior San benito County, but the latest satellite imagery shows a progressive clearing of the cloud cover over western and central Contra Costa County and areas near the San Pablo and northern San Francisco Bays. Expecting more stratus clearing to continue through the morning and early afternoon hours today. Will monitor the expected development of a distinct marine layer inversion through the day as the larger scale pattern turns to ridging over the West Coast.
DialH
, 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.
..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.
(12z TAFS) Issued at 437 AM PDT Wed May 6 2026
MVFR to VFR stratus is blanketing most terminals this morning. The forecast trend is fairly straightforward with clearing in the late morning or early afternoon, moderate onshore winds in the afternoon and early evening, and the return of stratus overnight. The marine layer will be fully reformed by Thursday morning, with lower ceilings expected.
Vicinity of SFO, MVFR stratus is filling in the Bay and is now impacting the big 3 terminals. The cloud layer is somewhat patchy over SFO and the southern portion of the SF Bay, and the ceilings may go scattered at times this morning. More pronounced clearing is expected around 18-20Z with strong onshore winds developing this afternoon.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, The stratus deck is more patchy across the southern terminals, and MRY has somehow dodged a ceiling thus far. That being said, it could reach the terminal at any point over the next several hours. Expect clearing in the afternoon before stratus returns overnight with lower cloud bases expected.
(today through Monday) Issued at 437 AM PDT Wed May 6 2026
High pressure over the eastern Pacific will maintain gentle to moderate northerly breezes over the coastal waters today. Fresh to strong northerly breezes develop Thursday afternoon and continue through the weekend, building rough seas across exposed waters.
Ca, None. PZ, Small Craft Advisory from 9 PM Thursday to 3 AM PDT Friday for Pt Arena to Pt Reyes 0-10 nm.
Small Craft Advisory from 9 AM Thursday to 3 AM PDT Friday for Pt Pinos to Pt Piedras Blancas 0-10 nm.
