, Issued at 201 AM PDT Sun May 3 2026 (Today and tonight)
Onshore winds continue to carry clouds and cooler air farther inland. 24 hour trends show cooler to much cooler air is reaching the higher elevations of the forecast area as well. Temperatures vary from the 50s to the 40s at 1 am. A cloudy, chilly start and continuation of cool air advection will slow the diurnal warming process today. There may be spotty light drizzle. Forecast highs are in the 60s today though it may be difficult to break out of the 50s along the immediate coastline. The best chance of the Sun breaking through the clouds will be farthest inland from late morning through afternoon. Onshore winds, low clouds and chilly temperatures prevail tonight. A few additional patches of light drizzle are possible.
..issued at 201 AM PDT Sun May 3 2026 (Monday through Saturday)
Residual polar jet stream winds on the back side of the 500 mb closed low currently to our west will have already merged with subtropical jet stream winds by Monday. By Monday the center of the 500 mb low is forecast to be located over the Central Coast to the Sierra Nevada/westernmost NV. The forecast gets a little more challenging later Monday and early Tuesday with respect to wet weather potential over our forecast area. Our current official forecast carries light rain (0.10" or less) developing over the North Bay and the East Bay and dry elsewhere during this time. However, something to keep in mind is recent output e.g. from the ECMWF/GFS/NAM show greater measurable rain later Monday and early Tuesday. Lingering cold air aloft, with the 500 mb low cold core, including possibly temporarily surface cooled air i.e. higher surface pressures locked over the highly varied terrain of CA while the mechanism for rainfall in this case becomes warm air advection at ~ 850 mb to 700 mb (up to ~ 10K feet up) arrives from the north and interacts with the colder air. At this time per model forecasts it's forecast as stratiform precipitation vs convective/unstable. Precipitable water is still forecast to peak 0.90" to 1" during this time. If the wetter pattern does develop, it'd bring more widespread beneficial light to moderate rain across more of our forecast area. Stay tuned to further updates.
From mid to late week high pressure aloft moves in from the west and northwest. Compressional warming within the high will steepen 850 mb temperatures well above normal and likewise with the help of the May Sun angle, surface temperatures will warm well above normal for early May. A quick check on forecast 850 mb temps on the ECMWF show readings nearing the 90th percentile on Oakland upper air sounding climatology for the time of year. Daytime surface high temperatures far from any cooler maritime influences will climb to the 80s to lower 90s by late in the week.
(12z TAFS) Issued at 438 AM PDT Sun May 3 2026
Predominantly MVFR CIGs through late this morning/early afternoon. Low to moderate confidence in the second half of the forecast period. HREF guidance shows low clouds across the region for much of the day but recent guidance shows these CIGs staying just above 3000 ft (3500- 5000 ft). With the marine layer deepening and mixing out as upper level troughing dominates the short term forecast, it doesn't seem out of the question for OVC/BKN conditions to prevail but stay above that 3000 ft threshold. As such, went with a slightly more optimistic TAF that keeps OVC/BKN conditions within the VFR category. Increasing confidence in VFR conditions for the second part of today is that ceilings have been rising over the last few hours with most sites on the MVFR/VFR border. It will definitely need to be watched closely with the potential for the marine layer to win out and MVFR conditions to prevail for much of today/tonight. Otherwise, winds generally stay onshore with locally breezier afternoon and evening conditions expected.
Vicinity of SFO, MVFR with VFR conditions returning by late morning. Low to moderate confidence that CIGs will stay overcast but within the VFR category this afternoon/tonight. This is supported by GFS-MOS, GFSLAMP, and HRRR guidance with only the more pessimistic NAM-MOS showing MVFR conditions returning around 05/06Z. If MVFR conditions do return tonight they would likely last through the end of the TAF period but cloud cover may become more patchy towards the end of the period. Breezy onshore winds return during the afternoon/evening but did not see any major signs of stronger gusts returning today.
SFO Bridge Approach. Similar to SFO.
Monterey Bay Terminals, CIGs are on the MVFR/VFR threshold with predominantly MVFR conditions expected through late this morning/early afternoon. Low to moderate confidence that VFR conditions will return this afternoon with CIGs hanging between 3500- 5000 ft. There is some potential for MVFR CIGs to dominant the entire forecast period but leaned towards CIGs staying just above MVFR due to HRRR guidance and recent GFS-MOS and GFSLAMP guidance. Breezier onshore winds return during the afternoon/evening with gusts between 15 to 20 knots expected at SNS.
(today through Friday) Issued at 438 AM PDT Sun May 3 2026
Winds continue to diminish and seas continue to subside through the remainder of the morning. A gentle to moderate northwest breeze and moderate seas are expected to prevail this afternoon into the early work week. Winds to increase and seas to build late week into next weekend.
Issued at 438 AM PDT Sun May 3 2026
Long period northwest swell, with periods of 15 seconds or above, is expected to arrive along the Pacific coast today. These long period swells increase the risk of sneaker waves and rip currents, particularly as the period between swell impulses results in lulls of around 20 to 30 minutes before larger sets of waves arrive. Due to the dangers, a Beach Hazards Statement for all Pacific coast beaches remains in effect until 11 PM Sunday night. Never turn your back to the ocean! Don't be fooled by calmer seas; observe the waves for at least 20 minutes before approaching the coast.
Ca, Beach Hazards Statement through this evening for CAZ006-505-509- 529-530.
PZ, None.
