, Issued at 1202 AM PDT Tue Oct 27 2026 (Today and tonight)
Satellite imagery reveals some patchy stratus developing mainly over the higher elevations of the Bay Area and Central Coast, but also extending to a patch over Monterey Bay itself. Stratus development overnight remains somewhat uncertain but some expansion is expected through the morning hours with stratus dissipating through the late morning and early afternoon hours.
The weather pattern continues to be dominated by a large scale ridge with an axis over the Pacific Northwest, as an embedded low reinforces the larger pattern and brings the troughing influence farther south into northern and central California. Highs remain relatively cool for this time of year with middle to upper 60s expected in the interior valleys, the lower 70s in the warmest parts of extreme southern Monterey County, lower to middle 60s close to the Bays, and the upper 50s to lower 60s along the Pacific coast. Gentle to moderate onshore winds will develop this afternoon with gusts reaching 20 to 30 mph along the coast, through favored gaps and passes, and at the ridgelines.
A combination of high astronomical tides and surge from thermal expansion effects brings the risk of minor coastal flooding along the Bayshore at the San Pablo, San Francisco, and Monterey Bays, and the Pacific coast, at high tide today. At the San Francisco tidal gauge, high tide is expected to be 2.1 ft above normal (7.9 ft MLLW) at 12:15 PM Tuesday 10/27, including around 1.2 ft of surge residual partially attributed to impacts from El Nino.
..issued at 1202 AM PDT Tue Oct 27 2026 (Wednesday through Monday)
Troughing will continue to impact the region through the work week. The trough pattern will get reinforced through Wednesday as a cut- off low forming over British Columbia migrates southwards, allowing a low pressure system flowing in from the central Pacific to merge into a trough axis that will extend down the West Coast and persist into the upcoming weekend. The net result will be a continued gradual cooling trend across the region with highs dipping into the middle 50s to middle 60s across the lower elevations by the latter part of the week.
For the Halloween weekend, confidence for significant rainfall has decreased since yesterday, especially across the SF Bay Area, where probabilities for rainfall have decreased to around 10-30% and measurable rainfall chances have all but vanished. The greatest chances for measurable rainfall remain around Monterey and San Benito Counties, and there rain totals are expected to be light with the probability of wetting rains (rain totals above 0.1") rather low (below 15%). Remember that last night, NBM guidance at the Monterey Airport suggested that for the 48 hour period beginning 5 AM PDT Saturday the 31st and ending 4 AM PST Monday the 2nd (note the time change, as this period includes the "fall back" from Daylight Savings Time) suggested that the 90th percentile rainfall total (a reasonable worst case scenario, with a 10% probability that the final total exceeds this value) was 1.6 inches. Now, for the same period, that 90th percentile value has dropped to 0.3 inches. It looks like the model trend is leaning more and more towards the bulk of the rainfall impacting southern California, and even there the forecast remains low confidence. An active weather pattern remains possible through the early part of next week, but any details are hard to pin down and ensemble model cluster analysis continues to depict a variable solution space that's mainly focused around how fast the troughing and ridging come through the western United States.
Coastal flooding concerns continue across Bayshore locations within the San Pablo, San Francisco, and Monterey Bays and the Pacific coastal regions through Friday. At the San Francisco tidal gauge, high tide is expected to be 1.9 ft above normal (7.7 ft MLLW) at 12:56 PM Wednesday 10/28, 1.7 ft above normal (7.5 ft MLLW) at 01:43 PM Thursday 10/29, 1.6 ft above normal (7.4 ft MLLW) at 02:39 PM Friday 10/30, and 1.0 feet above normal (6.8 ft MLLW) at 03:44 PM on Saturday 10/31, including around 1.2 ft of surge residual partially attributed to impacts from El Nino.
(12z TAFS) Issued at 439 AM PDT Tue Oct 27 2026
Scattered cumulus clouds are bringing passing VFR to high MVFR ceilings to the terminals this morning. Skies are more clear in the North Bay, which has allowed enhanced radiational cooling, and some patchy fog is being reported at both STS and APC. This fog will clear by 18Z, with widespread VFR conditions expected through the rest of the day as high clouds roll in. Boundary layer winds are from the NW, with moderate strength expected through the day.
Vicinity of SFO, Currently VFR with a 3,800' ceiling. There is a high (90%) chance VFR conditions persist through the morning and it's nearly certain they will hold through the afternoon. WNW winds ramped up early this morning, and will remain moderate to strong through the day.
SFO Bridge Approach, While ceilings are above 3,000' at SFO and San Mateo Bridge, they are less than 4,000' at Palo Alto and similar ceilings could impact San Jose at any time. These approach clouds should clear between 20-22Z.
Monterey Bay Terminals, Both SNS and MRY are expected to hold on to VFR conditions through the day, but there is a large cloud bank east of SNS that could bring VFR ceilings this morning. Otherwise winds will be diurnally driven, with moderate strength in the afternoon.
(today through Sunday) Issued at 439 AM PDT Tue Oct 27 2026
Buoys are reporting a fresh NW breeze across the coastal waters this morning. Winds will increase to a strong breeze by this afternoon, building rough seas across exposed waters. Conditions will gradually start to improve Thursday as winds decrease to and seas subside.
Ca, Coastal Flood Advisory until 5 PM PDT Friday for CAZ006-505-506- 508-509-529-530.
PZ, Small Craft Advisory until 9 PM PDT this evening for Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory from 3 PM to 9 PM PDT Wednesday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 9 PM PDT Wednesday for Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 9 AM this morning to 9 PM PDT Wednesday for Pigeon Pt to Pt Pinos 10-60 NM.
