Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

929 pm PDT Sat aug 1 2026

Short Term

, Issued at 1220 PM PDT Sat Aug 1 2026 (This evening through Sunday night)

The satellite picture reveals more extensive stratus coverage offshore compared to yesterday at this time, and patches of cloud persist across the coast of the Marin Headlands and the Monterey Bay region, where an eddy over the bay is keeping the stratus in place for a little while longer. The marine layer remains relatively compressed and stratus coverage will be rather limited tonight owing to a couple factors including an approaching weak cold front and possible bursts of offshore wind.

The weather pattern continues to be dominated by the high pressure system centered over the Desert Southwest and extending over the state, which is leading to widespread temperatures above the seasonal averages today. Highs today range from the upper 80s to middle 90s in the inland valleys today, with warm spots in the far interior North Bay, the eastern part of Contra Costa County, and southern Monterey and San Benito Counties seeing highs reaching the triple digits (up to 107 in southern Monterey County). Elsewhere, highs along the bays range from the middle 70s to the middle 80s, while the Pacific coast hovers in the middle 60s to lower 70s. On Sunday, morning lows range from the middle 50s to lower 60s in the lower elevations, to the middle 60s to the lower 70s in the higher elevations, and expect highs to be broadly similar to today's, possibly a couple degrees warmer in some spots.

A weak cold front currently off the coast of California, and associated with an upper level trough over the Pacific Northwest and British Columbia, will help tighten the north- south pressure gradient as it comes into the northern Bay Area and the adjacent waters before dissipating, with the latest model projections putting tonight's peak SFO-ACV gradient in the -7 to -8 mb range. A gradient this strong will help mix out the stratus and promote stronger winds in the coastal waters, with gale force gusts widespread and isolated storm force gusts possible. Fortunately these strong winds remain generally parallel to the coast, but a weak offshore push is possible tonight across the North Bay and Central Coast, which could cause warmer and drier conditions to extend all the way to the coast. Another stronger pulse of offshore wind is possible Sunday night into Monday morning. Not strong enough for a Wind Advisory, but strong enough to raise the fire weather concerns.

Widespread Moderate HeatRisk persists across the interior regions into Monday with patches of Moderate HeatRisk persisting into the rest of the week. This corresponds to a moderate risk for heat related illnesses for sensitive populations, including children, the elderly, pregnant women, people with certain medical conditions, and people who work or live outdoors without adequate shelter or hydration. Some patches of Major HeatRisk, corresponding to a more widespread risk for heat-related illnesses, are also expected in the warmest parts of the interior Central Coast. Follow these tips to avoid heat-related illnesses:

* Stay hydrated and drink plenty of fluids. * Wear lightweight, light-colored clothing. * Reduce time spent outdoors or stay in the shade. * Never leave people or pets unattended in vehicles. * Use sunscreen if going to the coast or the pool.

As a final note, beach hazards and fire weather concerns continue. See the BEACHES and FIRE WEATHER sections for more details. One less spark, one less fire, and never turn your back to the ocean!

Long Term

..issued at 1220 PM PDT Sat Aug 1 2026 (Monday through next Friday)

The heat continues into Monday as the trough passes by far to the north across the northern Rockies and western and central Canada, leaving the ridging pattern generally intact through the early part of next week. Subtle cooling is possible in the wake of this trough passage Tuesday and Wednesday, with coverage of the Moderate HeatRisk becoming patcher in the inland SF Bay Area on those days. Breezy onshore winds are expected each afternoon and evening, and the longer range guidance shows temperatures rebounding for the latter part of the week as the ridge rebuilds over the region.

Aviation

(06z TAFS) Issued at 926 PM PDT Sat Aug 1 2026

VFR at all terminals is expected to persist past midnight with Monterey Bay terminals expected to develop IFR ceilings soon after. A struggling marine layer along with a weak fetch of offshore flow that will develop in the pre-dawn hours and continue through the day Sunday should keep the interior terminals VFR through the forecast period.

Vicinity of SFO, VFR. Low confidence in chances of MVFR/IFR ceilings developing in the hours surrounding sunrise Sunday morning. VFR continuing through the overnight and Sunday seems more likely where the potential for more potent offshore flow is highest.

SFO Bridge Approach, Similar to SFO.

Monterey Bay Terminals, HiRes guidance has high confidence in IFR/LIFR ceilings developing with less confidence in exact timing, most likely will be soon after midnight with VFR by early afternoon and stratus returning soon after sunset Sunday evening.

Marine

(tonight through next Friday) Issued at 926 PM PDT Sat Aug 1 2026

Rough to very rough (9-14 ft) wind driven seas will continue to build through Sunday from strong to near gale force northwest winds. Our northern coastal zones and the Big Sur coastline will have frequent gale force gusts and occasional storm force gusts. The southerly long period swell will continue to weaken tonight into Sunday.

Beaches

Issued at 229 AM PDT Sat Aug 1 2026

Long period southerly to southwesterly swell continues through the afternoon, bringing hazardous beach conditions to the Central Coast and the San Francisco Bay Area. Southerly swell will weaken by late this afternoon with conditions to drop below Beach Hazards Statement criteria. Diminishing, low long period (1-2 ft at 13 to 14 seconds) southerly swell will continue into next week. Sneaker waves and strong rip currents will be the primary threats through the duration of the Beach Hazards Statement, with breaking waves up to 10 feet along some south and southwest facing beaches and break points, such as Santa Cruz, Pacifica, and parts of Stinson or Ocean Beach. This can be particularly surprising when wave heights increase suddenly after a period of seemingly tranquil wave action. In fact, sneaker waves can have 20+ minutes in between the larger sets (breaking waves) with significant "flat/calm looking" times between them. Due to the long period, sneaker waves are powerful and can catch beachgoers by surprise, resulting in people and pets being swept into the cold, turbulent ocean. Rip currents are strong enough to pull even the strongest swimmers away from shore. Check marine conditions before you head out! Swim near a lifeguard, if possible. Maintain a safe distance from the water, and stay away from jetties, piers, beachside rocks, and other waterside infrastructure. Never turn your back to the ocean and if you have small children or pets at the beach, please keep an eye on them.

Watches, Warnings, Advisories

Ca, None. PZ, Gale Warning until 9 PM PDT Sunday for Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 5 AM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

Gale Warning until 3 AM PDT Monday for Pt Arena to Pt Reyes 10- 60 NM.

Small Craft Advisory until 9 AM PDT Monday for Pigeon Pt to Pt Pinos 10-60 NM.

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