Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

942 pm PDT Fri jul 10 2026

Short Term

, Issued at 127 PM PDT Fri Jul 10 2026 (This evening through Saturday night)

Strengthening high pressure over southern California is shifting eastward toward the Desert Southwest. This has result in a gradual warming and drying trend across the interior and higher elevations that will persist through early next week. Meanwhile, a persistent marine layer around 1,000 feet will gradually compress to around 500 feet over the weekend and maintain cooler conditions near the coast. Thus, afternoon maximum forecast temperatures today will be in the upper 50s to 60s near the coast, 60s/70s around the bays and locations adjacent to the bays, and 80s to middle 90s inland. Meanwhile, the warmest interior locations of the Monterey County have a greater than 70% probability of reaching 100 degrees F.

Again for tonight, may see some mist/light drizzle at the coast as low clouds push locally inland into the coastal adjacent valleys. Otherwise, temperatures look to cool into the 50s overnight into Saturday morning for most lower elevations. However, the higher elevations (especially across the Central Coast) will only cool into the 60s to lower 70s as the aforementioned high pressure continues to build.

For Saturday, temperatures continue to warm by a few degrees with mostly Minor HeatRisk with pockets of moderate in the warmest interior valleys.

Long Term

..issued at 127 PM PDT Fri Jul 10 2026 (Sunday through next Thursday)

Saturday night and into Sunday is when we forecast monsoonal moisture to advect around the western periphery of the high pressure over the Desert Southwest. This area of high pressure will continue to strengthen as it shifts northeastward into the Intermountain West Sunday and into Monday with Precipitable Water values reaching between 1.00-1.25" across much of the region. There remains a great deal of uncertainty in the model guidance with respect to the amount of MUCAPE (lifting mechanism) to support high-based thunderstorms. The mid/upper level moisture will be in place and we have fairly high confidence in this. Thus, expect widespread mid-to-high level clouds to stream across the region with virga (precipitation not reaching the surface). As the moisture profile deepens Monday into Tuesday we expect a slight chance of high- based rain showers across the Bay Area and Central Coast. All that being said, this is considered a low probability, high impact scenario if thunderstorms are able to develop, the fire weather threat is high. We will continue to monitor the potential for high-based convection closely!

With respect to temperatures, warm and dry conditions are likely to persist through much of next week when we see more widespread Moderate HeatRisk across the region Monday though Wednesday. The exception will be coastal locations as the marine layer is forecast to remain around 500 feet in depth. Maximum afternoon temperature warm slightly (especially inland) through early next week and so do the overnight lows, this explains the more widespread Moderate HeatRisk. The amount of mid-to-high level clouds may limit how warm the afternoons get but also would limit radiative cooling as well.

Beyond Wednesday, the 500 MB Heights and Anomalies indicate high pressure will remain parked over the Four Corners region and/or Intermountain West. This will keep temperatures slightly above seasonal averages with near normal precipitation.

Aviation

(06z TAFS) Issued at 935 PM PDT Fri Jul 10 2026

The marine layer stratus bank is regaining organization over the ocean, while inland locations within the marine layer see clouds develop overhead. This combination of cloud formation and advection makes the exact timing of arrival very tricky. The forecast still leans on persistence, but the confidence is onset timing is pretty low. I feel better about the clearing times in the morning, however.

Vicinity of SFO, VFR as of this writing, but the walls are closing in. OAK is reporting ceilings of 1,000 feet, with HAF at 700. When SFO does get their ceiling, the height should be in that ballpark.

SFO Bridge Approach, Will fill in later than SFO and clear earlier.

Monterey Bay Terminals, I have no idea what will happen in the next few hours. The Monterey Bay is clear, but there is a small patch of clouds over the Monterey Peninsula that is occasionally drifting over Jack's Peak to the terminal and retreating back. Eventually IFR conditions will settle in for the night, but I just can't say when with any confidence tonight.

Marine

(tonight through next Thursday) Issued at 935 PM PDT Fri Jul 10 2026

A fresh NW breeze will diminish to moderate this weekend, as seas gradually diminish. These more favorable conditions will continue into early next week before strong winds return late week.

Beaches

Issued at 450 AM PDT Thu Jul 10 2026

A Beach Hazards Statement remains in effect for Pacific coast beaches through this 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.

Watches, Warnings, Advisories

Ca, 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 9 PM PDT Sunday for Pt Arena to Pt Reyes 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.

Small Craft Advisory until 3 PM PDT Monday for Pt Arena to Pt Reyes 10-60 NM.

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