Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

456 am PDT Mon Oct 12 2026

Short Term

, Issued at 1123 PM PDT Sun Oct 11 2026 (Tonight through Tuesday)

Upper level troughing continues across the West Coast through mid- week before the trough progresses eastward. If you stepped outside today it likely felt like the first real breath of fall. Highs largely peaked in the 60s to low 70s Sunday. Temperatures ran about 5 to 10 degrees below normal today with the 850 mb temperature (9C at the 00Z launch) between the 10th and 25th percentiles. This trend continues Monday with high temperatures in the 60s to low 70s and overnight lows (Monday morning) largely in the 40s. The exception will be across the higher elevations where a few locations may drop into the 30s. For comparison, we typically see high temperatures in the mid to upper 70s across the interior this time of year. By Tuesday, the center of the upper level low will start to progress eastward while upper level ridging starts to rebuild along the coast. This will kick off a slight warming trend (2-4 degrees) and bring more interior locations into the low to mid 70s while coastal areas stay in the 60s. Low temperatures Tuesday morning will be similar to Monday with lows in the 40s to low 50s across most of the region and pockets of 30s across the higher elevations.

Light rain is possible along the Big Sur Coast and southern Monterey County early Monday morning but no real accumulation is expected. More typical onshore winds return Monday as the SFO-WMC pressure gradient shifts positive (onshore) again. Diurnally breezy winds continue for favored locations (coastal areas, mountain gaps and passes) and over the marine environment. Fire weather concerns diminish Monday/Tuesday given the decreasing winds and improved daytime humidity values. A Coastal Flood Advisory remains in effect through 3PM Tuesday but may need to be extended into Wednesday for the entire bay shoreline. It will depend on how high tides get Monday/Tuesday and if tidal heights are trending down enough for the advisory to be expired on time Tuesday night.

Long Term

..issued at 1123 PM PDT Sun Oct 11 2026 (Tuesday night through next Sunday)

Our brief glimpse of fall will quickly become a distant memory by late week as temperatures heat up again. The upper level trough continues to progress eastward Tuesday into Wednesday with upper level ridging becoming dominant Wednesday onwards. Much warmer temperatures are expected for the second half of the week with above normal temperatures returning Thursday into the weekend. Wednesday will be a transition day between cooler early week temperatures and hot late week temperatures with seasonal to slightly above normal temperatures anticipated. High temperatures will be 10 to 15 degrees above normal Thursday through Saturday. Interior locations will be in the 80s to 90s while coastal areas peak in the 70s to low 80s. Much drier conditions are expected late week with a return of daytime humidity values dropping into the 10s. Elevated fire weather conditions are likely late week as much warmer and drier conditions return. Fortunately, no major signals that winds will be gusty around this time which should help mitigate at least some of the risk. As always, if you are participating in an activity that involves fire or towing anything, make sure to prevent sparks from spreading as fuels are very dry/flammable. Moderate HeatRisk returns late week into the weekend so make sure to take breaks in the shade, drink plenty of water, and reduce time outdoors during peak heating.

Aviation

(12z TAFS) Issued at 450 AM PDT Mon Oct 12 2026

VFR is expected to prevail through the forecast for all terminals. Weak offshore flow today from a weak otter eddy will be reinforced by larger scale ridging over the EPAC and progressive upper closed low to our west diving south that will begin to drive more offshore flow by the end of the forecast period.

Vicinity of SFO, VFR. Offshore flow and lack of a marine layer will result in mainly clear skies through the TAF period.

SFO Bridge Approach, Similar to SFO.

Monterey Bay Terminals, VFR is expected to prevail through the forecast period with the aforementioned periods of offshore flow.

Marine

(today through Saturday) Issued at 450 AM PDT Mon Oct 12 2026

Sea state will gradually improve today as northwest winds decrease across our coastal waters, however buoys are still reporting rough seas early this Monday morning. Long period swell increases to 16ft to 18ft by early Tuesday morning and gradually decreases through the rest of the work week.

Beaches

Issued at 1042 AM PDT Sun Oct 11 2026

Buoy reports this morning still indicated some solid swell entering the coastal waters. As such, still seeing an energetic the surf zone. Give the observed height and period isolated breaking waves 18-20 ft are possible at favored break points. Long period southerly swell will persist through the weekend, bringing an increased risk of sneaker waves and strong rip currents. The large tidal swings will also result in coastal erosion as water and waves are brought farther up the beach than normal, especially during high tide. Remain off jetties, piers, rocks, and other waterside infrastructure as waves can sweep across the shoreline without warning, pulling people into the sea. Remain out of the water to avoid hazardous surf and strong rip currents and never turn your back on the ocean!

MM

Watches, Warnings, Advisories

Ca, Beach Hazards Statement through this evening for CAZ006-505-509- 529-530.

Coastal Flood Advisory until 3 PM PDT Tuesday for CAZ006-508-529- 530.

Coastal Flood Advisory until 4 PM PDT Wednesday for CAZ506.

PZ, Small Craft Advisory until 9 AM PDT this morning for Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 3 AM PDT Tuesday 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.

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