Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

555 pm PDT Thu jul 30 2026

Short Term

, Issued at 1216 PM PDT Thu Jul 30 2026 (This evening through Friday night)

Generally clear skies prevail over the region with limited patches of stratus lingering over the western side of San Francisco, along the coast of the San Mateo Peninsula down to Pillar Point, and at the immediate coast of the Monterey Bay region. Today will be the first day of a warming trend that will dominate the weather pattern for the next few days and bring temperatures above seasonal averages to the inland regions, driven by a building high pressure system expanding into California from the Desert Southwest. High temperatures will range from the middle 80s to middle 90s across the inland valleys, up to around 102 within the warmest spots of southern Monterey and San Benito Counties, the lower 70s to lower 80s along the Bays, and the lower to middle 60s along the Pacific coast. An onshore push will develop this afternoon and evening, bringing gusts of 25 to 35 mph along the coast, through gaps and passes, and within the Salinas Valley.

Tonight, expect the building high pressure system to compress the marine layer, limiting any stratus and fog impacts to the immediate coastal regions. Low temperatures on Friday morning range from the middle to upper 50s in the valleys, to the 60s and lower 70s within the thermal belts. Highs on Friday will continue to warm with temperatures around a couple degrees warmer than today's across most of the region, save the immediate coast where the compressed marine layer keeps the region cooler.

Patches of Moderate HeatRisk develop in the interior on Friday, followed by more widespread Moderate HeatRisk in the interior Saturday through the early part of next 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. 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.

Long Term

..issued at 1216 PM PDT Thu Jul 30 2026 (Saturday through next Wednesday)

Saturday looks to be the warmest day of this strand of warming with triple digit highs possible in the far interior regions of northern Sonoma, northeastern Napa, and eastern Contra Costa counties, while southern Monterey County sees highs reaching 105 with some isolated and heavily favored locations making a run for 110. Elsewhere the inland valleys remain in the 90s while downtown San Francisco and Oakland hover in the middle 70s to lower 80s. On Sunday, a trough passing by the Pacific Northwest will interrupt the building ridge and cause temperatures to plateau, but large scale ridging returns the next day and could continue into the middle of the next week.

Regarding potential strong winds across the coastal waters this weekend, the ECMWF EFI backed down a little bit from what the previous forecaster was seeing last night, but are still showing high EFI values with a strong shift of tails. Or in layman's terms, there's a strong signal for strong winds and a relatively high probability for remarkably strong winds, a "boom" situation, if you will. The PG&E WRF model continues to show a swath of storm force gusts over 60 mph across the northern waters off the coast of Sonoma and Marin counties, but it's almost alone in depicting this, with the deterministic GFS and the experimental RRFS showing isolated storm force gusts in the area while the NAM12 and deterministic ECMWF keep wind gusts at gale force. Will be interesting how the other high resolution models, namely the higher-resolution NAM and the HRRR, depict the wind gusts in this are where the time comes. For now, there wasn't enough confidence to bump up the wind gusts for the weekend.

In addition, the upper level pattern could bring us a couple of offshore bursts over the region, with a notable pulse Sunday night into Monday particularly across the North Bay and SF Bay regions. As noted by the previous forecaster, the fire weather concerns regarding nocturnal drying and downslope warming are obvious, but that downslope warming could also cause coastal temperatures to be much warmer than the forecast if it extends through Monday.

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

Aviation

(00z TAFS) Issued at 554 PM PDT Thu Jul 30 2026

Mainly clear skies are being observed across much of the Bay Area and Central Coast, with the exception being smoke drifting south and eastward from the Woodside Fire in Sonoma County. VFR conditions are expected to prevail tonight and into tomorrow for the majority of the region, as the marine layer compresses to about 500-800ft and high pressure builds in. Areas that have the best chance for stratus development tonight are around the Monterey Bay and perhaps around Half Moon Bay. Some models hint at it building back into the Napa region and around Oakland, but confidence is low and opted to continue the hint of stratus at these sites. Medium to high confidence in the forecast.

Vicinity of SFO, Breezy onshore winds with gusts to 25-28kt will gradually decrease this evening, with winds gradually falling to less than 10kt overnight. The tougher question is in regard to the stratus forecast. As mentioned above, the marine layer is expected to be around 500-800ft with the KOAK sounding showing a fairly dry profile. Current thinking is KFSO will likely stay VFR through the period and if any low clouds try to form it'd likely be between 10- 14Z. Outside of that look for breezy onshore winds to return Friday afternoon and evening, sustained speeds will be around 15kt with gusts up to 20-23kt possible. Medium to high confidence in the forecast.

SFO Bridge Approach, Similar to SFO.

Monterey Bay Terminals, The most likely area to see stratus late tonight and into Friday morning is the Monterey Bay and northern Salinas Valley. The question for here though, is how will the compressed marine layer factor things? Will we get another night of LIFR cigs and perhaps even pockets of fog or will be bottom out with IFR cigs. Opted to keep the optimistic forecast for IFR cigs tonight, but with no major changes in the general pattern, LIFR cigs are possible again around or shortly after sunrise. Skies clear by mid morning, with VFR conditions prevailing afterwards. Medium to

Marine

(tonight through next Wednesday) Issued at 554 PM PDT Thu Jul 30 2026

Fresh northwest breezes increase to strong across our coastal waters by Saturday as moderate seas build to rough. Gale force winds in the northern waters increase by Sunday, thereby allowing seas to become very rough. Very rough seas subside to moderate by Wednesday. A long period southerly swell continues to impact our coastal waters from distant tropical activity.

Beaches

Issued at 1216 PM PDT Thu Jul 30 2026

Long period southerly to southwesterly swell of 14-17 seconds continues to impact our coastline through at least Saturday afternoon, bringing hazardous beach conditions to the Central Coast and the San Francisco Bay Area. Sneaker waves and strong rip currents will be the primary threats, 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, Beach Hazards Statement through Saturday afternoon for CAZ006- 505-509-529-530.

PZ, Small Craft Advisory until 9 PM PDT this evening for Mry Bay-Pt Reyes to Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge.

Small Craft Advisory until 9 AM PDT Saturday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

Gale Warning from 9 AM to 3 PM PDT Saturday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory from 3 PM Friday to 3 PM PDT Saturday 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 from 9 AM to 3 PM PDT Saturday for Pigeon Pt to Pt Pinos 0-10 nm.

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

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