Marine Weather and Tide Forecast for Los Altos Hills, CA

SHORT TERM
(This evening through Saturday)
Issued at 137 PM PDT Fri May 16 2025

Mostly clear sky conditions have returned to the region this afternoon. Afternoon temperatures will be within a few degrees (-5 to +5) of seasonal averages. However, passing high clouds continue over the region. Low clouds are likely to return tonight and into Saturday morning, and push further inland, as we have abundant low level moisture.

Coastal drizzle will also be possible Saturday morning as the marine layer deepens overnight. Low clouds spreading further inland, the deepening of the marine layer, and an approaching trough of low pressure will result in a slight cool down for Saturday afternoon. Maximum forecast high temperatures will range from the mid 50's to mid 60's on northwest facing coastal locations to upper 60's to mid 70's across the interior.
Northwesterly winds are expected by Saturday afternoon with gusts 25-35 mph in lower elevations across the region with stronger gusts up to 45 mph in the higher elevations and just along the North Bay coast.

LONG TERM
(Saturday night through next Thursday)
Issued at 137 PM PDT Fri May 16 2025

Winds ease slightly Saturday night into Sunday morning, with the exception of the higher elevations. Breezy and gusty winds will persist on Sunday afternoon with similar values mentioned above, maybe a tad bit stronger. The aforementioned upper level trough will dig into the Great Basin through Sunday before ejecting further to the east. This will result in northerly, potentially offshore winds in the higher elevations and typically windy gaps and passes of Napa, Contra Costa, Alameda, and Santa Clara counties Sunday night into Monday. This will lead to elevated fire weather conditions as humidity values will be in the 40-50% range Sunday night and as low as 15% on Monday afternoon (again in the higher elevations).

High pressure will begin to build into the Pacific Northwest and northern California in wake of the exiting trough with the warmest day currently anticipated to be Wednesday. Temperatures Wednesday afternoon look to be 5-15 degrees above seasonal averages with mid 60's to mid 70's for coastal areas, mid 70's to lower 80s across the bayshore, and mid 80's to lower 90's across the interior. More of a zonal flow is expected by late next week with the likely return of a shallow marine layer and more seasonal temperatures.

AVIATION
(00Z TAFS)
Issued at 423 PM PDT Fri May 16 2025

VFR is expected to persist through much of the evening, until coastal stratus and patchy fog produce /IFR- MVFR/ cigs, primarily after midnight. Gusty northwest winds aloft will result in periods of low level wind shear at KSTS Airport 12z-17z Saturday morning.

Vicinity of SFO...VFR is expected to persist through much of the evening with /IFR- MVFR/ cigs set to settle in after midnight.
Gusty westerly winds will produce wind gusts at or exceeding 35 knots at times this evening, with an Airport Weather Warning in place until 9 PM tonight. Similarly gusty winds are expected to develop Saturday afternoon and evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals.. MVFR due to coastal stratus developing tonight, a few patches of light drizzle are possible as well. Cigs may break at times until late in the overnight, when MVFR cigs are expected to persist through the day and evening hours with the development of steady onshore winds from 10 to 20 knots, strongest from Saturday afternoon into the evening hours.



MARINE
(Today through Wednesday)
Issued at 1045 AM PDT Fri May 16 2025

Gusty to strong northwest winds will continue over the coastal waters today through the weekend, including much of early to mid next week. Hazardous marine conditions with rough to very rough seas will continue through Tuesday night.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory until 3 PM PDT Saturday for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-SF Bay N of Bay Bridge.

Gale Warning until 3 PM PDT Saturday for Pt Arena to Pt Reyes 0- 10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Reyes to Pigeon Pt 0- 10 nm.

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