, Issued at 1203 AM PDT Thu Oct 29 2026 (Today and tonight)
Satellite imagery shows high clouds across the region, the byproduct of a decaying upper level low from the west that is merging into the troughing pattern across the West Coast. Cloudy conditions will likely persist through the day today as morning lows hover in the lower to middle 40s in the inland valleys and the upper 40s to the lower 50s closer to the coasts, while highs remain in the upper 60s to the lower 70s in the inland valleys and the SF Bayshore and the lower to middle 60s along the Pacific coast. Winds will generally remain light and gentle with some breeziness in the afternoon and evening hours in favored locations.
Now to address the elephant in the room. Several high-resolution models, including the HRRR and the experimental RRFS, are showing some simulated reflectivity returns coming in later this morning and continuing through the day across the region, but especially focused on the South Bay and the Central Coast. On the surface it seems like rain should be in the forecast, but other meteorological analysis comes in and says "Not so fast!". Looking at the 00Z (5 PM PDT) sounding from Oakland reveals a deep layer of very dry air stretching from the 850 mb layer to the 500 mb layer where dew points range from around -30 to -50 degrees Centigrade. That is a three-mile thick column of air that any potential precipitation will have to overcome for rain to develop, and whether we'll get anything making it to the surface depends on whether developing cells can overcome that dry layer. The current forecast leans towards "no" with anything seen on KMUX radar today evaporating before it reaches the ground, or virga. We can't dismiss the possibility of rain completely, but it looks to be something that at most brings a few sprinkles or hundredths of an inch of rain to the mountaintops over something that would be more impactful.
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 1.9 ft above normal (7.7 ft MLLW) at 01:43 PM Thursday 10/29, including around 1.2 ft of surge residual partially attributed to impacts from El Nino.
..issued at 1203 AM PDT Thu Oct 29 2026 (Friday through Wednesday)
High temperatures in the inland valleys will fluctuate in the middle 60s to the lower 70s through the seven day outlook. Large scale troughing remains in place through the next couple days before chances for rain come into the region later on Saturday into Sunday. As the trough starts to push its way eastwards into the West Coast, a upper level jet streak will take aim at the central and southern portions of California. This will facilitate cyclogenesis and a developing surface low takes aim at southern California and the northern portions of Baja California. Those regions will see the bulk of the rain from this system, but the fringes of the moisture will come into the Central Coast and will likely give the interior measurable rain, if not much rain. Forecast rain totals are still fluctuating, but the interior portions of Monterey and San Benito Counties should see around a tenth to a third of an inch of rain Saturday into early Sunday. Elsewhere, light showers are possible within the Monterey Bay region and even extending into the South Bay, especially if the parent system takes a more northerly track.
A progressive ridge will come into the region Sunday into Monday before another system comes in towards the end of the seven-day outlook. Last time I had stated that the speed and track of that incoming system was highly uncertain. That remains the case judging from the ensemble model cluster analysis and even just looking at various model outputs heading into the middle of next week. The current forecast retains the rain chances for the end of the seven- day outlook, but by necessity they are low (10-30% probability) and the certainty in any further detail is lower still.
Coastal flooding concerns continue across Bayshore locations within the San Pablo, San Francisco, and Monterey Bays through Saturday and the Pacific coastal regions through Friday. At the San Francisco tidal gauge, high tide is expected to be 1.6 ft above normal (7.4 ft MLLW) at 02:39 PM Friday 10/30, and 1.1 feet above normal (6.9 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 444 AM PDT Thu Oct 29 2026
VFR. Weak offshore flow continues this morning with a gradual shift to weak onshore flow later today and tonight. The marine layer will still struggle to reorganize through the forecast period with a slight chance of MVFR ceilings developing tonight into early Friday morning.
Vicinity of SFO, VFR. As mentioned above, weak offshore flow will continue through this morning before a gradual shift to onshore flow by later today and tonight.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR. Weak onshore flow develops this afternoon with a slight chance of MVFR ceilings returning early this evening into Friday morning.
(today through Tuesday) Issued at 444 AM PDT Thu Oct 29 2026
Conditions gradually improve today with strong northwest breezes becoming fresh to moderate with rough seas improving as well. Improving conditions will continue into the weekend while a long period west-northwest swell arrives this weekend and continues into next week.
Ca, Coastal Flood Advisory until 6 PM PDT Saturday for CAZ006-506- 508-529-530.
Coastal Flood Advisory until 5 PM PDT Friday for CAZ505-509.
PZ, Small Craft Advisory until 9 PM PDT this evening for Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory until 3 PM PDT this afternoon for Pigeon Pt to Pt Pinos 10-60 NM.
