Marine Weather and Tide Forecast for Foster City, CA

SHORT TERM
Issued at 1243 PM PDT Thu Oct 8 2026 (This evening through Friday night)

A Heat Advisory remains in effect until 10 PM this evening for much of the interior Bay Area and Central Coast as 500 mb high pressure remains in place over the region. Temperatures across the interior will be in the some 10-20 degrees F above seasonal averages again this afternoon with cooler conditions near the coast given the shallow marine layer around 500 feet in depth.

Overnight temperatures will still remain warm in the higher terrain tonight with 60s to low 70s expected and generally in the 50s in the lower elevations. This is as a mid/upper level trough begins to develop off of the British Columbia coastline and allows for the marine layer to deepen.

Friday will be noticeable cooler as the aforementioned trough deepens along the West Coast bringing temperatures closer to normal for this time of year. Thus, expecting temperatures to cool into the low-to- upper 80s in the inland valleys and the warmest interior portions of the region to reach into the lower 90s.
Breezier onshore winds are also expected on Friday afternoon and evening along the coast and wind-prone gaps, passes, and valleys.
This will keep temperatures near the coast in the 60s to lower 70s.

A Coastal Flood Advisory remains in effect for bayshore locations adjacent to the San Pablo Bay with up to 1.2 feet of inundation above ground level in low-lying areas during times of peak high tides. On Friday morning, the areas adjacent to the San Francisco Bay and Monterey Bay are added to the advisory through at least 3 PM Tuesday.

LONG TERM
Issued at 1243 PM PDT Thu Oct 8 2026 (Saturday through next Wednesday)

Additional cooling is expected by Saturday as a dry frontal boundary drops southward across the Bay Area and Central Coast and the mid/upper level trough deepens along the West Coast. Thus, temperatures will cool to below seasonal averages Saturday through early next week. Onshore winds will be a bit stronger than those on Friday with gusts between 30-40 mph along the coast and in the wind- prone gaps, passes, and valleys. Locally stronger gusts will be possible in these areas this weekend.

The NBM and global forecast models continue to indicate a chance for rain showers across the southern portion of the Bay Area and Central coast Sunday evening through Monday. This is as an upper level cut- off low pressure system and remnant moisture from Tropical Storm Rachel push into the Central Coast. However, not expecting widespread measurable rainfall at this time. Winds ease late Sunday and into early next week as the through axis shifts inland. Cooler conditions are forecast to persist through midweek as troughing persists over the West Coast. Then, as we head into the latter part of the upcoming week, a gradual warming trend is forecast by the WPC Cluster Analysis as high pressure builds in from the eastern Pacific.

AVIATION
(18Z TAFS)
Issued at 1037 AM PDT Thu Oct 8 2026

Patchy fog and LIFR stratus lingers at the immediate coast with the rest of the region remaining VFR through the daytime. A gentle to moderate onshore pattern wind develops in the afternoon and evening hours. This evening and tonight, the marine layer is expected to rebuild and thicken as large scale ridging moves eastwards, allowing for some improved inland expansion of the stratus deck. Forecast confidence is moderate for stratus extent and ceiling heights, but expect some inland development into the North bay valleys, SF Bay, and Salinas Valley overnight. Stratus begins to retreat back to the coastal regions Friday morning.

Vicinity of SFO... Moderate confidence for VFR conditions through the TAF period with some scattered clouds possible late tonight.
Higher confidence in stratus impacts at OAK. Moderate west-northwest winds will develop in the afternoon and evening hours, with light winds overnight into the morning.

SFO Bridge Approach... Similar to SFO

Monterey Bay Terminals... Lingering fog and LIFR stratus is expected to lift imminently at MRY but potentially persist through the afternoon along the immediate coast. Otherwise VFR conditions remain prevalent through the day with gentle to moderate northwest winds in the afternoon hours. IFR-LIFR stratus develops this evening with moderate confidence for fog, not expected to clear out until the TAF period ends on Friday morning, or shortly thereafter.

MARINE
(Today through Tuesday)
Issued at 907 AM PDT Thu Oct 8 2026

Moderate to fresh northwesterly breezes and moderate seas will prevail today. Conditions deteriorate Friday and into the weekend as northerly breezes increase to become strong to near gale across the coastal waters, Monterey Bay, and through the Golden Gate Gap. Gale force gusts are expected across the northern outer waters and the coastal jet region of Point Reyes. These winds will build rough to very rough seas. Long period southerly swell arrives Friday, with long period northwesterly swell arriving Sunday, creating a confused sea state.

FIRE WEATHER
Issued at 428 AM PDT Thu Oct 8 2026

Hot and dry conditions will lead to elevated fire weather conditions across the interior and higher terrain Thursday. Temperatures 10 to 20 degrees above normal and poor minimum relative humidity will continue away from the compressed marine layer at the coast Thursday. The higher terrain will experience active thermal belting, little-to-no recovery with nocturnal drying across the highest peaks, and thus prolonged burn periods. Winds remain the limiting factor, with diurnal winds prevailing except for light northerly/offshore flow overnight across the higher terrain. Even though conditions become cooler and more humid Friday, windier conditions will keep elevated fire weather conditions across the interior and higher terrain through Friday.

Sarment

MTR WATCHES/WARNINGS/ADVISORIES
CA...Coastal Flood Advisory from 9 AM Friday to 3 PM PDT Tuesday for CAZ006-508-529-530.

Heat Advisory until 10 PM PDT this evening for CAZ503-504-506- 508-510-512>518.

Coastal Flood Advisory until 4 PM PDT Wednesday for CAZ506.

PZ...Small Craft Advisory from 3 AM to 3 PM PDT Friday for Pt Arena to Pt Reyes 10-60 NM.