Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

934 pm PDT Tue Oct 27 2026

Short Term

, Issued at 215 PM PDT Tue Oct 27 2026 (This evening through Wednesday night)

A chill is in the air! Weak, persistent troughing continues over the West Coast keeping a cooler airmass locked in place over us. High temperatures stay in the 60s across the interior and 50s to low 60s along the coast while overnight lows drop into the 40s. Pockets of the North Bay, the Gabilan Range, and the Eastern Santa Clara Hills will see morning lows drop into the upper 30s. Daytime high temperatures are running 5 to 10 degrees below normal with the 850 mb temperature running anywhere from 7C to 11C (between the mean and 25th percentile). Conversely, overnight lows are anywhere from seasonal to slightly below normal to slightly above normal (higher elevations) for this time of year. So while it may feel chilly in the morning, remember it could always be chillier for this time of year. Diurnally breezy winds continue along the coast and across mountain gaps/passes during the afternoon and evening with occasional gusts between 20 to 30 mph. The windiest conditions are expected late this afternoon/evening with weaker winds expected along the coast on Wednesday.

Coastal flooding peaked early this afternoon and will continue to diminish through the remainder of the week. Today's tides came in at 2.01 ft above normal (7.85 ft MLLW) with the peak occuring at 12:24 PM. High tides will peak at 1.9 ft above normal (7.7 ft MLLW) at 12:56 PM on Wednesday. High tides are due to a combination of high astronomical tides and surge from thermal expansion effects bringing moderate coastal flooding to the Bay Area and Pacific Coast. The worst flooding is expected along bayshore Marin County with numerous reports of flooding coming in over the last few days. If you have any photos or documentation of coastal flooding from October 2026 please share them with us on social media so we can better document coastal flooding impacts.

Long Term

..issued at 215 PM PDT Tue Oct 27 2026 (Thursday through next Monday)

Seasonal to below normal temperatures continue through the long term forecast with rain potentially returning over the weekend and again next week. Broadly speaking, high temperatures on Friday will be in the mid to upper 60s across the interior and 50s to low 60s along the coast. Temperatures are then expected to cool, becoming below normal across the entire region, with highs dropping into the 50s to low 60s Saturday and Sunday. This drop occurs as the first upper level disturbance arrives late Friday into Saturday and brings another round of much cooler air with it. It also brings just enough moisture for light rain to spread across the region Saturday and Sunday. We aren't expecting wetting rains (> 0.10" of rain) outside of the Santa Cruz mountains, Santa Clara Hills, and the Santa Lucia Range. Trick or treaters may experience more drizzly conditions to some light rain but the worst looks to hold off until after 10 PM on Saturday. Heading into next week, guidance continues to show another deep upper level trough pushing inland but the timing of its arrival remains in question. Recent ensemble guidance shows more pronounced ridging and warming occurring Monday and Tuesday with the trough now arriving midweek. This correlates to warmer temperatures early next week with interior highs getting back into the upper 60s to low 70s. Rain chances start to increase late Monday into Tuesday with initial guidance showing light rain between a tenth of an inch to half an inch falling early next week. Shower activity continues beyond the end of the current forecast period so the exact amounts we are expecting will continue to fluctuate. Definitely worth keeping an eye on the forecast as we head into next week with our multiple chances for rain.

Coastal flooding concerns continue through Friday with tidal heights to be on the downswing Thursday and Friday. The current forecast has high tide peaking 1.7 ft (7.5 ft MLLW) above normal at 1:43 PM on Thursday, 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. The caveat to this is that the anomaly has been running higher than initially forecast so the Coastal Flood Advisory may need to be extended into the weekend for all regions rather than continuing for just the North Bay.

Aviation

(06z TAFS) Issued at 934 PM PDT Tue Oct 27 2026

VFR is forecast except for patchy valley fog /IFR-LIFR/ developing tonight and Wednesday morning. Surface high pressure will build into the Great Basin and onshore winds will shift to offshore tonight and Wednesday morning.

Vicinity of SFO, VFR. West wind 5 to 10 knots becoming light northeasterly Wednesday morning. West wind around 12 knots redevelops Wednesday afternoon and evening.

SFO Bridge Approach, Similar to SFO.

Monterey Bay Terminals, VFR. Onshore winds 5 knots becoming light easterly tonight and Wednesday morning, then onshore 10 knots Wednesday afternoon and early evening.

Marine

(tonight through next Monday) Issued at 926 PM PDT Tue Oct 27 2026

Northwest breezes continue this evening across the waters, with isolated near gale force gusts occurring over the northern water waters. Seas will continue to build in response, leading to rough seas across exposed waters. Conditions will gradually improve Thursday as winds decrease and seas subside.

Watches, Warnings, Advisories

Ca, Coastal Flood Advisory until 5 PM PDT Friday for CAZ006-505-506- 508-509-529-530.

PZ, 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 2 AM PDT Wednesday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

Small Craft Advisory until 9 PM PDT Wednesday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.

Visit this site often? Consider supporting us with a $10 contribution.
Learn more