Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

503 pm PDT Thu jul 9 2026

Short Term

, Issued at 1256 PM PDT Thu Jul 9 2026 (This evening through Friday night)

High pressure strengthening across southern California will build northeastward over the Desert Southwest over the weekend. As such, a gradual warming and drying trend is forecast through the weekend and into early next week. 850 mb temperatures look to reach between 23- 25 degrees C during this timeframe. However, generally Minor HeatRisk are expected with pockets of Moderate HeatRisk across the far interior areas through the weekend. Thus, afternoon maximum forecast temperatures today will be in the 60s near the coast, 60s/70s around the bays, and 80s to middle 90s inland. Meanwhile, the warmest interior locations of the Monterey County have a greater than 60% probability of reaching 100 degrees F.

Tonight, expecting mist/light drizzle to impact the coast at times with low clouds forecast to push locally inland into the valleys. However, widespread rainfall is highly unlikely. That said, not expecting as widespread coverage as this morning with the marine layer forecast to compress. Temperatures for Friday will be similar to those this afternoon. Friday night looks to be more of the same, low clouds near the coast will return back inland with temperatures generally in the 50s across the lower elevations. However, the building high pressure over the Desert Southwest will result in warmer temperatures in the higher elevations where 60s to lower 70s are expected.

Long Term

..issued at 1256 PM PDT Thu Jul 9 2026 (Saturday through next Wednesday)

We are still expecting mid/upper level moisture to be advected northward as southerly winds aloft on the periphery of the high pressure over the Desert Southwest. This will be most notable Sunday into Monday and potentially lasting through Tuesday night. However, the limiting factor remains instability at those levels with MUCAPE forecast to remain less than 500 J/kg based off of the latest CAMs. That said, the GFS has little to no CAPE across our region, yet the mid/upper level moisture looks highly likely. So the threat for high based convection still appears to be low at this time. We'll continue to monitor the higher resolution models with each subsequent model run(s) for the potential high based convective.

By Monday and Tuesday we begin to see more Moderate HeatRisk across the interior. This is as overnight lows are forecast to increase as a result of the building high pressure early next week. That said, mid/upper level cloud cover (as a result of the mid-level sub- tropical/tropical moisture) may limit surface heating. However, onshore winds and a shallow marine layer will remain present, keeping conditions cooler near the coast. In the extended, high pressure is forecast to remain parked over the Desert Southwest with troughing off of the Pacific Northwest coast.

Aviation

(00z TAFS) Issued at 457 PM PDT Thu Jul 9 2026

The marine layer is about 800 feet deep, compared to 1,000 feet this time yesterday. Broadly speaking the aviation weather impacts will be similar to yesterday with low clouds pushing inland overnight. The difference is the inland extent and ceiling duration should be lessened. On the other hand the ceiling height will also be a couple hundred feet lower, and there will likely be more visibility impacts through the morning.

Vicinity of SFO, Will the clouds be able to spill over the Peninsula mountains. That's the biggest question of the night. If they do, the terminal will get a ceiling very soon. Otherwise it will hold off until at least 06Z as the clouds fill in the Bay first.

SFO Bridge Approach, Will likely stay clear for several hours longer than the terminal in either scenario described above.

Monterey Bay Terminals, MRY is already tucked into a stratus blanket for the night, while SNS will join the party soon. LIFR conditions are highly likely at MRY after what we saw this morning.

Marine

(tonight through next Tuesday) Issued at 457 PM PDT Thu Jul 9 2026

Rough northwest seas (9-11 ft) continue into the weekend and begin to subside to moderate (6-8 ft) by Monday. Strong northwesterly winds and near gale force gusts also begin to diminish to fresh breezes with strong gusts returning by Sunday.

Beaches

Issued at 457 PM PDT Thu Jul 9 2026

A Beach Hazards Statement remains in effect for Pacific coast beaches through Friday afternoon. Long period southwesterly swell will create an increased risk of sneaker waves and strong rip currents, as well as breaking waves up to 10 feet. This will be especially true for south and southwest facing beaches with moderate to steep slopes along the North Bay, San Francisco Peninsula, and Santa Cruz coasts. Sneaker waves can sweep across the shoreline without warning, pulling people into the sea from rocks, jetties and beaches. Dangerous swimming and surfing conditions and localized beach erosion can be expected. Stay off of jetties, piers, rocks, and other waterside infrastructure. Remain out of the water to avoid hazardous surf and NEVER turn your back on the ocean. Monitor local weather, surf and tide forecasts at www.weather.gov/mtr.

A Coastal Flood Advisory is in effect for minor high tide flooding through Thursday July 16th. The combination of a perigean spring tide (lunar perigee on 7/13 and new moon on 7/14) enhanced by 3-6 inches of additional water from thermal expansion and accumulated sea level rise since the tidal datum was established (1983-2001) will bring high tides up to 1.7 feet above normal. This will lead to minor flooding of parking lots, parks and roads with isolated closures expected. For context, in June we reached 2.0 feet above normal and in January we reached 2.5 feet above normal.

Issued at 425 AM PDT Thu Jul 9 2026

A Beach Hazards Statement remains in effect for Pacific coast beaches through Friday afternoon. Long period southwesterly swell will create an increased risk of sneaker waves and strong rip currents, as well as breaking waves up to 10 feet. This will be especially true for south and southwest facing beaches with moderate to steep slopes along the North Bay, San Francisco Peninsula, and Santa Cruz coasts. Sneaker waves can sweep across the shoreline without warning, pulling people into the sea from rocks, jetties and beaches. Dangerous swimming and surfing conditions and localized beach erosion can be expected. Stay off of jetties, piers, rocks, and other waterside infrastructure. Remain out of the water to avoid hazardous surf and NEVER turn your back on the ocean. Monitor local weather, surf and tide forecasts at www.weather.gov/mtr.

A Coastal Flood Advisory is in effect for minor high tide flooding through Thursday July 16th. The combination of a perigean spring tide (lunar perigee on 7/13 and new moon on 7/14) enhanced by 3-6 inches of additional water from thermal expansion and accumulated sea level rise since the tidal datum was established (1983-2001) will bring high tides up to 1.7 feet above normal. This will lead to minor flooding of parking lots, parks and roads with isolated closures expected. For context, in June we reached 2.0 feet above normal.

Watches, Warnings, Advisories

Ca, Beach Hazards Statement through Friday afternoon for CAZ006-505- 509-529-530.

Coastal Flood Advisory until 4 AM PDT Thursday for CAZ006-506- 508.

Coastal Flood Advisory from 8 PM Saturday to 4 AM PDT Wednesday for CAZ505-509-529-530.

PZ, Small Craft Advisory until 3 PM PDT Sunday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory until 3 AM PDT Friday for Pt Reyes to Pigeon Pt 0-10 nm.

Small Craft Advisory until 9 PM PDT Friday for Pigeon Pt to Pt Pinos 0-10 nm.

Small Craft Advisory until 3 AM PDT Saturday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

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