Marine Weather and Tide Forecast for Belvedere, CA

UPDATE
Issued at 850 AM PDT Sun Aug 16 2026

Water vapor imagery shows an upper level trough of low pressure off the California Coast and high pressure over the Desert Southwest this morning. As a result, California remains situated between the two, with south southwesterly flow aloft and a relatively deep marine layer along the coast, although not as deep as yesterday. In fact, the 12z KOAK sounding shows the atmosphere saturated between roughly 600 and 1800 feet. This corresponds well to the ceilings that we are seeing across our observing sites as well. Given the depth of the marine layer, we have seen some drizzle as well this morning, with a number of locations reporting a hundredth or two. The winner for drizzlefest though is Point Lobos, Mound Meadow, with 0.03 inches.

This deep marine layer will keep the area quite cool today, with temperatures staying below normal for the majority of the Bay Area and near normal for our fartherest inland areas and upper elevations. Current forecast seems to be handling this well, so no updates are planned at this time. One other note given that the marine layer was shallower this morning that yesterday, some of the upper elevations did not have as good of a humidity recovery.
This nocturnal drying trend will likely continue through the week, as the high pressure tries to expand into the area. Palmer

SHORT TERM
Issued at 1102 PM PDT Sat Aug 15 2026 (Tonight through Monday)

Heights will begin to rise Sunday as upper-level ridging nudges in from the east. We're already seeing an effect of this with a compressing marine layer bringing lower clouds and less inland extent. Sunday morning will offer another chance for drizzle along the coast and in the higher terrain. Temperatures will remain below normal under the marine layer influence with inland and higher elevation locations warming to near normal. Diurnal winds will keep smoke from the Timber Fire out to sea with downsloping (easterly)
winds in the morning and onshore (northwesterly) winds in the afternoon.

LONG TERM
Issued at 1102 PM PDT Sat Aug 15 2026 (Monday night through next Saturday)

Global ensemble clusters are in agreement that upper-level ridging will nose, and ultimately build, into the Intermountain West through Thursday. Sensible weather wise, locations inland from and above the compressed marine layer (~1,000 feet) will moderate to near to slightly above normal. Along the coast, temperatures will remain below normal with evening/morning clouds. To put this event into context, 850 mb temperatures will increase to the 75th-90th percentile; even so, no records are forecast. Even with the warming and drying trend, heat and fire weather impacts are expected to remain minor. Fire weather wise, seasonably elevated conditions with rapid rates of spread on any wind-and-terrain aligned starts in receptive vegetation will be possible in higher terrain, specifically with the diurnal sea breeze in the afternoons/evenings.

AVIATION
(18Z TAFS)
Issued at 1044 AM PDT Sun Aug 16 2026

Stratus, fog, patchy drizzle /MVFR-IFR-LIFR/ are steadily mixing out and dissipating otherwise it's VFR. Stratus, fog and patchy drizzle /MVFR-IFR-LIFR/ redevelop tonight and Monday morning.

Vicinity of SFO...Stratus /MVFR/ mixing out to VFR 1930z today.
Stratus /MVFR-IFR/ redevelops tonight and Monday morning. Low clouds /MVFR/ mixing out to VFR 20z Monday. West to northwest wind 5 to 15 knots.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Stratus /IFR/ improving to MVFR-VFR in the afternoon. Stratus /IFR/ redevelops tonight and Monday morning.
West to northwest winds 5 to 15 knots.

MARINE
(Today through Friday)
Issued at 850 AM PDT Sun Aug 16 2026

A gentle to moderate northwesterly breeze persists into Monday with localized fresh gusts possible across the interior waters.
Winds increase to fresh to strong late Monday and remain elevated through the end of the forecast period. Seas of around 4 to 5 feet will build to 7 to 8 feet by mid week. A long period southerly swell around 15 to 17 seconds will continue to diminish through the early work week.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...None.