Marine Weather and Tide Forecast for Irvine, CA

DISCUSSION
FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

Satellite imagery tonight shows marine layer low clouds along much of the southern California coastline and starting to creep inland.
These will make their way into parts of the inland valleys overnight, including parts of the Inland Empire. The marine layer will start to break up and retreat towards the coast again starting around 8 AM Wednesday morning, and will have mostly cleared by about 11 AM. A swath of mid to upper level clouds currently visibly passing through central California will move into the region from the morning through the late afternoon, however, preventing completely clear skies. Otherwise, expect overnight and Wednesday morning temperatures to be a bit warmer than this morning, with similar afternoon high temperatures to today. Otherwise, no significant change to the forecast was needed, and more details about the upcoming week can be found in the previous discussion below.

PREVIOUS DISCUSSION
Issued 117 PM PDT Tue Apr 29 2025

We have fair and warmer weather today, accented by some pretty cumulus clouds over the mountains. We can thank a fleeting ridge of high pressure aloft for the pleasant spring-like temperatures.
Within the broader longwave ridge pattern is a weak low pressure trough that develops Wednesday and Thursday right over SoCal. It will serve to bring cooler weather by a couple degrees, and also help rebuild the marine layer seemingly into a coastal low cloud forecast we can count on. And one that spreads coastal low clouds well inland each night and morning.

There is also some instability over the high desert and San Bernardino Mountains indicating a remote chance of thunderstorms Thursday and/or Friday, which we'll keep an eye on, but as of today the chance is pretty microscopic. Breezy onshore winds will increase through mountain passes and into deserts each afternoon and evening. Isolated pockets, such as through and east of the San Gorgonio Pass, should get gusts at or above 40 mph. Another fleeting ridge on Friday brings slightly warmer weather.

Then a big trough develops and deepens as it drops down the coast arriving in SoCal Saturday. Probably the biggest impact will be strong winds in all areas, but particularly in the mountains, deserts and coastal waters. It will also bring cold air, destabilizing the atmosphere, and not a lot of moisture, but enough for showers. Thunderstorms are also not out of the question late Sunday. Snow will fall in the mountains as the snow level drops quickly on Sunday morning (currently showing down to around 5,000 feet). There won't be a lot of precipitation, but some.
While confidence is high in the much cooler weather, the winds, and the showers, confidence is lower in the precipitation amounts.
Confidence is growing in the timing of the winds and precipitation: Saturday evening through Sunday looks like the stormiest time. We have less confidence on when the storm departs on Monday...ish. Tis the season for closed low pressure systems that separate from the jet stream and give forecasters fits, but this upcoming system doesn't look as capricious as usual. It does move slowly, so next Monday or Tuesday a tepid warming and drying trend appears to get underway.

AVIATION
300400Z
Coasts/Valleys
BKN-OVC clouds with bases 1000-1500 ft MSL impacting KSAN and KCRQ then KSNA after 06Z. Bases will lower to around 700 ft MSL between 08Z and 12Z with impacts at all coastal TAF sites. Bases rise to 1000-1200 ft MSL after 14Z. Low clouds and fog could extend up to 20 miles inland with about a 60 percent chance of CIGs and reduced VIS at KONT briefly around 15Z. Vis restrictions are expected where low clouds intersect higher coastal terrain. At least partial clearing expected at the coast between 17Z today and 02Z Thu.

Mountains/Deserts...Mostly clear skies tonight through Wed.

MARINE
No hazardous marine conditions are expected through Friday. Gusty west to northwest winds will develop over the coastal waters this weekend, with strongest winds Saturday night and Sunday. Peak gusts of 25 to 30 kt expected. Gale force winds are possible, with a 25 percent chance of winds reaching at least 34 kt in the outer coastal waters near San Clemente Island Saturday night into Sunday morning.

BEACHES
Elevated surf of 3 to 6 feet with sets to 7 feet will occur through Wednesday. Highest surf occurred on south facing beaches today and will gradually lower on Wednesday. Strong rip currents are expected.

SGX WATCHES/WARNINGS/ADVISORIES
CA...Beach Hazards Statement through Wednesday evening for Orange County Coastal Areas.

PZ...None.