, Issued at 909 PM PDT Fri Aug 28 2026 (Tonight through Sunday)
While there were some light showers Friday, the lightning never happened and that threat is now over. The 00Z sounding measured 1.32" of precipitable water. That's well over the 90th percentile (1.04"), and near the maximum recorded for this date (1.38"). Despite this near record moisture, dry air is moving in from the northwest remarkably fast. The ECMWF ensemble mean predicts the PW will drop from 1.38" Friday to around 0.5" Saturday. That means the atmospheric moisture is decreasing from well over the 90th percentile all the way down to the 10th percentile in only 12-24 hours.
As a result of the much drier air, the skies will be mostly clear Saturday. The marine layer is trying to re-organize, but any stratus will likely be patchy and evaporate in the mid to late morning. The mid and high level clouds are already clearing and will not return anytime soon. Despite the sunshine, temperatures will remain several degrees cooler than normal this weekend.
..issued at 909 PM PDT Fri Aug 28 2026 (Sunday night through next Friday)
Upper level troughing will persist through the week, with a few embedded shortwave features bringing some early rain to the Pacific Northwest. In the Bay Area, rain is less likely, but the cooling trend will continue through at least the middle of the week. Max temperatures will be roughly 10-15 degrees below normal from Monday through Wednesday. The 850 mb temperature is expected to drop below the 25th percentile (16.1C) by Tuesday morning.
(06z TAFS) Issued at 841 PM PDT Fri Aug 28 2026
It's VFR except for areas of stratus /MVFR-IFR/ along the immediate coastline. The mid-latitude wind flow pattern is returning with drying air tonight and Saturday. The GFS shows precipitable water quickly lowering tonight and Saturday, near the 10th percentile on Oakland upper air soundings for late August. With decreasing water vapor aloft this will result in radiative cooling and with lingering boundary layer moisture it's likely to continue cooling to saturation resulting in additional fog and stratus /IFR-LIFR/. Diurnal surface warming will mix out fog and stratus improving conditions to MVFR-VFR by late Saturday morning and afternoon. Stratus and fog /MVFR-IFR/ redevelop Saturday night.
Vicinity of SFO, VFR until tempo stratus /MVFR/ 06z-08z tonight, then stratus /MVFR/ prevailing tonight to 18z Saturday morning. Thereafter VFR is forecast Saturday afternoon to mid evening. West wind near 15 knots tonight decreasing to 8 to 10 knots late tonight and Saturday morning. West wind increasing to 15 to 25 knots Saturday afternoon and evening.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR then stratus /IFR-LIFR/ redevelops tonight and Saturday morning. Surface warming will mix out stratus by late Saturday morning and afternoon. Stratus /IFR/ redevelops Saturday night. West to northwest winds 5 to 15 knots.
(tonight through next Thursday) Issued at 834 PM PDT Fri Aug 28 2026
Fresh northwest breezes with occasional near gale force gusts continue through the weekend as well as a long period southerly swell. The long period southerly swell peaks on Saturday around 17 to 18 seconds and gradually diminishes by Sunday night. Wind driven seas briefly build to rough Saturday afternoon into Sunday and gradually subside to moderate through next week.
Ca, None. PZ, Small Craft Advisory from 9 AM Saturday to 3 AM PDT Sunday for Mry Bay.
Small Craft Advisory until 9 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm.
