Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

950 pm PDT Sat may 2 2026

Short Term

, Issued at 1201 PM PDT Sat May 2 2026 (This evening through Sunday)

Satellite imagery showed widespread stratus across the region this morning, in addition to high clouds streaming over the SF Bay Area, gradually eroding across the interior regions into the afternoon hours. This comes as a upper level low builds and strengthens off the West Coast, allowing the marine layer to expand and reinforcing the stratus development across the region. For today, there are some indications that the stratus layer will continue to scatter out, particularly in the inland valleys, but with the interaction with the higher clouds complicating the heating profile, this isn't a high confidence forecast. As it stands, high temperatures today range from the lower to middle 70s in the interior valleys, around 80 in the southern Salinas Valley, and the upper 50s to middle 60s along the Pacific coast and the Bays. Lower those interior temperatures around 5-10 degrees if the stratus layer does not scatter out today. For tonight, stratus clouds will return to the inland regions, with temperatures dropping into the middle 40s to middle 50s across most of the region, with some lower 40s possible in the coldest regions of southern Monterey County.

Conditions will be similarly cool on Sunday as the upper level low starts to edge into California, as high temperatures dip into the middle 60s to lower 70s for the inland valleys, while remaining in the upper 50s to middle 60s along the coast and the Bays.

A Beach Hazards Statement remains in effect through Sunday evening due to long period northwesterly swell, an increasing risk of sneaker waves and strong rip currents. See the BEACHES section for more information.

Long Term

..issued at 1201 PM PDT Sat May 2 2026 (Sunday night through next Friday)

The upper level low moves across California through Tuesday, resulting in an extended period of cool temperatures, thick marine layers, extensive stratus decks, and a slight chance for light rain and drizzle across the region, but mainly at the coast and within topographically favored locations. As the previous forecaster noted, residual precipitable water from an extension of the jet stream far to the north of Hawaii will move into the Bay Area, with model output showing around 0.9-1" of precipitable water coming to the SF Bay Area Monday night through Tuesday. This is above the 90th percentile value for precipitable water for this time of year. Rainfall totals for this period are generally paltry, with the ensemble model spread at San Francisco International Airport basically anywhere between a trace to near a tenth of an inch with a couple of outlier ensemble members pouring down with up to a half of an inch of rain by Tuesday night.

By Wednesday, the upper level low moves into the Great Basin and southern Rockies with ridging building back behind it, leading to a warming and drying trend in the region with highs rising to the 70s and 80s inland.

Aviation

(06z TAFS) Issued at 934 PM PDT Sat May 2 2026

High clouds are now obscuring low clouds around the region. However, enough terminals and webcams continue to advertise MVFR CIGs. Current taf package will keep MVFR CIGs well into Sunday afternoon. Late Sunday afternoon and Sunday night confidence decrease as the marine layer becomes less pronounced and begins to mix. That being said, hard to bet against stratus already there and HREF does show some clouds reforming. Breezy onshore flow will return again Sunday afternoon.

Vicinity of SFO, MVFR CIGs through the Sunday AM rush. VFR and gusts 20-25kt Sunday afternoon. MVFR CIGs return Sunday night.

SFO Bridge Approach, Similar to SFO.

Monterey Bay Terminals, MVFR CIGs for much of Sunday. Small window late Sunday afternoon where some SCT could occur.

Marine

(tonight through next Friday) Issued at 934 PM PDT Sat May 2 2026

High pressure to the north will maintain moderate to fresh northerly breezes through early Sunday morning. Seas will also subside on Sunday as winds continue to diminish. Moderate seas and a gentle to moderate NW breeze prevail Sunday into the early work week. Winds will gradually increase throughout the remainder of the work week.

Beaches

Issued at 1201 PM PDT Sat May 2 2026

Long period northwest swell, with periods of 15 seconds or above, is expected to arrive along the Pacific coast today. These long period swells increase the risk of sneaker waves and rip currents, particularly as the period between swell impulses results in lulls of around 20 to 30 minutes before larger sets of waves arrive. Due to the dangers, a Beach Hazards Statement for all Pacific coast beaches comes into effect at 11 AM today and remains in effect until 11 PM Sunday night. Never turn your back to the ocean! Don't be fooled by calmer seas; observe the waves for at least 20 minutes before approaching the coast.

Watches, Warnings, Advisories

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

PZ, None.

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