Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

510 am PDT Sat may 16 2026

Short Term

, Issued at 140 AM PDT Sat May 16 2026 (Today and tonight)

Water vapor imagery continues to show a trough of low pressure over the West, with a disturbance digging across Northern California early this morning. The fog imagery shows the leading edge of the high clouds associated with this disturbance making it into North Bay at this time, while other areas are still clear. These high clouds will be relatively shorted lived though, as this disturbance quickly dives into the Great Basin by this afternoon. That said, this disturbance will help reinforce the already moderate onshore pressures gradients across the region, with the upper level support at 925 mbs increasing to 55 kts as well, especially over the coastal waters. Therefore, given that we are continuing to see gusts in the 30 to 40 mph range, with an isolated gust up to 50 mph along the immediate coast and the coastal waters at this time, believe that it was prudent to issue a Wind Advisory for the immediate coast from 11 am today through 5 am on Sunday, all except Santa Cruz which is slightly more sheltered. Given the strong onshore gradient, expect high temperatures today to be similar to those of yesterday for the coastal areas, while inland areas will be several degrees cooler than those of yesterday. Palmer

Long Term

..issued at 140 AM PDT Sat May 16 2026 (Sunday through Friday)

Another disturbance will then rotate through the trough and dive into the Great Basin on Sunday, keeping moderate to strong pressure gradients going across the region. They will shift though, turning more northerly or northeasterly. The upper level support also weakens ever so slightly. Therefore, do not think a wind advisory will be needed on Sunday, but cannot rule it out completely, especially for the North and East Bay hills and mountains.

This broad trough will remain over the Intermountain West through the first part of the work week, with high pressure trying to reestablish itself off the West Coast. This will keep Northern and Central California situated between the two through at least Tuesday, with dry northerly flow aloft. At this point in time, it looks like the ridge may start to win out, with a warming trend possible, especially for our inland areas. Coastal areas though will likely fall back into our typical May gray pattern with nighttime and early morning low clouds and fog.

By the end of the work week though, the ensembles are hinting at another cut off low forming off of the California Coast. This will likely help reinforce the marine layer and help cool things down for the inland areas. Palmer

Aviation

(12z TAFS) Issued at 509 AM PDT Sat May 16 2026

Strong winds aloft continue to move through the region with some areas seeing LLWS concerns. Moderate to breezy winds linger through the mid morning with winds building across the region through the day. The strongest gusts will affect sites near the marine environment. Additionally, winds look to be much stronger over the ocean through the TAF period. The gusty winds over the ocean will lead to an increase in sea spay, causing poorer visibilities over the marine environment and at near coastal sites, such as HAF. Winds reduce into the night, but remain moderate to breezy along the coast and lighter for sites inland.

Vicinity of SFO, VFR through the TAF period. Breezy winds increase and become strong into the late morning with gusts expected to exceed 30 kts by the mid afternoon. These stronger winds last into the night before reducing. Gusts look to cut off and winds turn more moderate into early Sunday morning.

SFO Bridge Approach, Winds will be more northerly with slightly weaker gusts.

Monterey Bay Terminals, LLWS affects MRY through the mid morning due to light southwest winds at the surface and stronger northwest winds around 800 ft AGL. Winds increase into late morning and afternoon becoming breezy and gusty across the area. Gust cut off and winds reduce into the night , but stay strong aloft with MRY seeing additional LLWS conditions until the late night.

Marine

(today through Thursday) Issued at 509 AM PDT Sat May 16 2026

Widespread gale force gusts are developing across the marine environment . Strong northerly winds will increase further through the weekend, with storm-force warnings going in effect for the northern outer waters and the inner waters south of point pinos Saturday afternoon. The rest of the waters look to have near or infrequent storm force gusts during that time. Storm warnings degrade into gales for Sunday. Winds begin to ease into that night and into the early work week. Expect rough seas through the weekend with up to 19 ft waves during the strongest winds, but seas will also ease into the work week.

Beaches

Issued at 140 AM PDT Sat May 16 2026

A Beach Hazards Statement remains in effect for west facing beaches along the Pacific Coast through 9 AM Monday due to strong winds over the marine environment leading to hazardously strong wind waves and overall rough seas. Dangerous swimming, boating, and surfing conditions can be expected. Large breaking waves can overpower swimmers resulting in significant physical injury and increase the risk of drowning. Gusts will stay strong along the immediate coast, causing blowing and drifting sand and increased sea spray. Water rescue attempts may be hampered by reduced visibilities from the sea spray. Remember, NEVER turn your back on the ocean.

Watches, Warnings, Advisories

Ca, Beach Hazards Statement through Monday morning for CAZ006-505- 509-530.

Wind Advisory from 11 AM this morning to 5 AM PDT Sunday for CAZ006-505-509-530.

Coastal Flood Advisory from 10 PM this evening to 3 AM PDT Tuesday for CAZ506.

PZ, Small Craft Advisory until 3 AM PDT Sunday for SF Bay N of Bay Bridge.

Gale Warning from 3 AM to 9 PM PDT Sunday for Pt Pinos to Pt Piedras Blancas 0-10 nm-SF Bay N of Bay Bridge.

Gale Warning until 9 PM PDT Sunday for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

Gale Warning until 3 PM PDT this afternoon for Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

Storm Warning from 3 PM this afternoon to 3 AM PDT Sunday for Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0- 10 nm.

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

Gale Warning until 3 AM PDT Monday for Pigeon Pt to Pt Pinos 10- 60 NM.

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