Marine Weather and Tide Forecast for Petaluma, CA

SHORT TERM
Issued at 1200 AM PDT Thu Apr 16 2026 (Today and tonight)

A dry cold front has begun moving south through northern Sonoma and Napa Counties late tonight and will continue to push its way south through our area throughout the overnight hours. The strongest gusts are likely to occur in the higher elevations, through the gaps and passes of the Mayacamas and Vaca mountains in Napa County and farther south through the East Bay Hills in the afternoon.
Ultimately, can't rule out some isolated gusts up to 50 MPH at the highest peaks in Napa County but otherwise impacts should be limited at lower elevations.

There has been a slight shift east in deterministic guidance of the sharpening upper trough that will produce the offshore flow through Friday morning. The timing of the strongest 925MB winds is late in the day today near sunset over the Bay Area and the Santa Cruz Mountains. Probabilities for gusts greater than 40MPH are very low, below 1000ft elevation. Furthermore, as the lower boundary layer begins to decouple around sunset, chances of the stronger winds aloft mixing to the surface decrease. Overnight temperatures will be cooler than normal, as winds ease in the hours before sunrise. Clear skies will result in efficient radiational cooling with some near freezing temperatures in the Santa Lucias in southern Monterey County, mostly 40s everywhere else.

A progressive, high amplitude ridge will move onshore over the course of the day Friday with noticeably warmer temperatures and light winds, will be a very pleasant day area wide. Temperatures will be in the mid-70s inland and low to mid-60s along the coast.

LONG TERM
Issued at 1200 AM PDT Thu Apr 16 2026 (Friday through Wednesday)

Overnight lows Friday night into Saturday will begin to rebound closer to normal while daytime highs jump another few degrees inland for another pleasant day across our area. A pattern change sets in late Saturday night into Sunday. Most of our area should see at least some wetting rains between Sunday and Tuesday, however consensus is poor across deterministic guidance for how the first and subsequent waves eject east out of the upper trough as it approaches the coast. The official forecast attm has slight chance PoPs in the North Bay as soon as Sunday morning, however significant uncertainty exists attm.

AVIATION
(12Z TAFS)
Issued at 455 AM PDT Thu Apr 16 2026

Areas of low clouds and patchy fog /MVFR-LIFR/ continue to develop under a combination of radiative cooling and lower level cool air advection. A cold front over the north Central Coast continues to move southward. The air mass will steadily dry out today through Friday morning. Offshore winds will prevail by later today and tonight. Low level wind shear has been added to the Bay Area TAFs for tonight and Friday morning. Currently the ACV-SFO pressure gradient has steepened to 6.8 mb, UKI-STS is moderate at 1.3 mb. The WMC-SFO pressure gradient is forecast to strengthen to near 10 mb tonight and Friday morning.

Vicinity of SFO...VFR. West wind increasing to 25 to 32 knots today, wind decreasing and becoming northwest to northeast 5 to 10 knots tonight and Friday morning. Low level wind shear develops tonight and Friday morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Low clouds /MVFR-IFR/ mixing out to VFR later this morning, VFR for the afternoon through tonight and Friday. West to northwest winds gusty 15 to 25 knots today, winds decreasing to light and variable tonight then southeast 5 to 10 knots late tonight and Friday morning.

MARINE
(Today through Tuesday)
Issued at 433 AM PDT Thu Apr 16 2026

A weak cold front will sweep across the coastal waters early this morning. The passing front will bring fresh to near gale breezes to the coastal waters and bays through today. These winds will build rough seas of 10-12 feet across the outer coastal waters.
Winds will ease back to moderate northwest breezes Friday through Saturday, allowing seas to gradually subside.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for Mry Bay.

Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

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

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