Marine Weather and Tide Forecast for Las Lomas, CA

SHORT TERM
Issued at 149 AM PDT Fri May 1 2026 (Today and tonight)

Steady and cool northwest winds continue over the coastal waters with sea surface temperatures varying from 54F to 59F (~ 2F to 3F above May normals). Coastal stratus continues to develop with an inland intrusion taking place per satellite and surface observations.
A lower to mid level thermal ridge is capping stratus clouds while a clear sky above is allowing nocturnal radiative cooling.
Currently, a 500 mb height ridge extends from the eastern Pacific to northern California, the Pacific Northwest, Alberta and Saskatchewan. Air temperatures currently vary from the mid 40s to 50s in the lower elevations to the 60s in the higher elevations, where it's milder within the lower level temperature inversion.

Stratus clouds will clear to the coastline under peak diurnal mixing later today. Daytime highs will climb a few degrees above early May normals inland to near normal along the immediate coast.
High temperatures will vary from the 60s coastside, 70s bayside to the lower to mid 80s far inland. Tonight, the aforementioned 500 mb ridge will shift eastward and weaken allowing for cooling aloft to commence. Coastal stratus redevelopment and onshore breezes will potentially usher stratus farther inland tonight and Saturday morning.

LONG TERM
Issued at 149 AM PDT Fri May 1 2026 (Saturday through Thursday)

An eastward moving 500 mb open wave trough approaching the Pacific Northwest will close off by late today. Behind the 500 mb trough a sharpening 500 mb ridge will become unstable, further supporting the closing off 500 mb low. This often happens when polar jet stream winds are unable to follow sharp 500 mb ridge contours, first heading eastward then flowing back westward, carving out and closing off a 500 mb low to the south. This 500 mb low will move south while the 500 mb ridge also closes off to the north, forming a Rex block pattern over the weekend and early next week. Dynamic cooling aloft with lowering 500 mb heights over our area will deepen the marine layer, with further cooling taking place and potentially producing periodic light drizzle and/or light rain.
It's a low confidence forecast in terms of how much precipitation may result. At the moment it does not look like very much i.e. up to a few hundredths; model forecasts are varying in solutions. Stay tuned to updates.

The Rex block is not forecast to last very long, it's likely to begin weakening and breaking down by the middle of next week. The subtropical jet stream attaches to the base of the closed 500 mb low over the weekend and early next week assisting with ejecting the low eastward mid to late next week. Btw, the strength of the subtropical jet stream is likely in response to recent surface water warming over lower latitudes. The 500 mb low getting picked up by the subtropical jet stream allows the polar jet stream over the Pacific to help move things along to the east as well, ushering in a newly arriving 500 mb mid-latitude trough with the potential for showery weather over northern California late next week.

AVIATION
(06Z TAFS)
Issued at 1004 PM PDT Thu Apr 30 2026

No major changes to the forecast as stratus continues to slither into the region. Cigs will generally be around MVFR levels, with the potential for IFR along the coast and perhaps into the North Bay valleys early tomorrow morning. Cigs are expected to clear by mid to late morning, with VFR conditions returning for the afternoon and early evening hours. Though stratus will return tomorrow evening.
Medium to high confidence in this forecast.

Vicinity of SFO...The stratus arrived a bit earlier than expected based on the last set of TAFS, with MVFR cigs holding over the terminal. Winds have begun to ease and should drop to less than 10kt over the next few hours. Expect conditions to begin clearing between 15-18Z, with cigs completely clearing between 18-20Z. Tomorrow afternoon, another round of breezy westerly winds are expected.
Stratus should return between 00-03Z Saturday. Medium to high confidence in this forecast.

SFO Bridge Approach...Similar to SFO. MVFR cigs should cover the a portion of the bay this evening and may fill in the southern half of the San Francisco Bay tonight. Clouds may clear a bit faster than KOAK and KSFO in the morning. Low to medium confidence.

Monterey Bay Terminals...Just when you think you have a handle on the stratus, it throws you a curve ball. With that being said, MVFR cigs hug KMRY down to Big Sur and flirt around KSNS this evening.
The best guidance that captures this is the HRRR and NAMNest, with KSNS seeing MVFR cigs return around 09Z. There is some uncertainty if we'll actually hit IFR conditions at KMRY and KSNS, with KMRY having the better chances. Opted to keep the cigs around OVC007 there and put KSNS at OVC010 instead. Clearing begins by mid to late morning, with VFR cigs expected for the afternoon. Stratus returns once again late tomorrow afternoon and into the early evening.
Medium to high confidence in this forecast.

MARINE
(Tonight through next Wednesday)
Issued at 903 PM PDT Thu Apr 30 2026

Fresh to strong northwest breezes will continue into Saturday with winds becoming moderate to fresh by Sunday. Winds will be strongest over the northern outer waters where winds will result in moderate seas building to between 10 to 12 feet. With easing winds, seas will begin subside by late Saturday with conditions improving through the remainder of the weekend.

MTR WATCHES/WARNINGS/ADVISORIES
CA...Beach Hazards Statement from Saturday morning through Sunday evening for CAZ006-505-509-529-530.

PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for Pt Arena to Pt Reyes 0-10 nm.

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