Swell Matrix

Area Forecast Discussion

National Weather Service San Diego CA

426 pm PDT Thu apr 30 2026

Update

Ation and Marine Discussion,

A 568 mb area of low pressure is currently moving over the northern Baja California coast. This is leading to scattered high level clouds across the southern portions of our forecast area. Elevated winds out of the west can also be expected later this afternoon and evening across the mountain slopes into the deserts with winds gusting near 25-40 MPH. This system will continue to push eastward throughout the day as a weak area of high pressure takes its place. This will lead to warmer weather for your Friday with high temperatures warming another 5 degrees over all with similar temperatures expected on Saturday. The marine layer will continue to be fairly deep with low clouds expected each morning for parts of the coastal basin.

Models are in good agreement in a closed low descending from the north over the weekend. This system looks to move somewhere not far off the SoCal coast by Sunday, pushing inland Monday and Tuesday. As the system approaches the region on Sunday, temperatures from Saturday to Sunday will lower around 5 to 10 degrees across all areas. The weather system will also increase winds across the region, with widespread westerly wind gusts 25-45 MPH across the mountains and deserts each afternoon and evening. As the system moves over SoCal, there will be the chance for light rain to occur from the coast to the mountains. The system's moisture profile continues to look limited, so chances for precipitation is near 15-25% for these areas. There may be drizzle/light showers by Monday morning, but the best chance for rain across the region will be on Tuesday as the core of the system passes by. Accumulations look light to none, highest across the coastal slopes of the mountains.

Models start to struggle a bit by the middle and end of next week regarding the weather system mentioned above. Some want to delay the system into Wednesday, others do not. Regardless, after the weather system passes, a weak ridge will move in its place, bringing warmer and drier weather for the end of next week with less wind.

Synopsis

Low pressure to the south will contribute to high level clouds across the region for the remainder of the day into the evening. Weak high pressure over the region on Friday and Saturday will lead to a warming trend with high temperatures 5 to 10 degrees above normal. Low pressure off the coast will move inland, leading to cooler and breezier conditions starting Sunday into the first half of next week. This system has a low chance to bring light rain showers to areas from the mountains to the coast on Monday and Tuesday. Fair and warmer weather is expected by the middle and end of next week.

Discussion

For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,

, Updated Aviation and Marine Discussion,

A 568 mb area of low pressure is currently moving over the northern Baja California coast. This is leading to scattered high level clouds across the southern portions of our forecast area. Elevated winds out of the west can also be expected later this afternoon and evening across the mountain slopes into the deserts with winds gusting near 25-40 MPH. This system will continue to push eastward throughout the day as a weak area of high pressure takes its place. This will lead to warmer weather for your Friday with high temperatures warming another 5 degrees over all with similar temperatures expected on Saturday. The marine layer will continue to be fairly deep with low clouds expected each morning for parts of the coastal basin.

Models are in good agreement in a closed low descending from the north over the weekend. This system looks to move somewhere not far off the SoCal coast by Sunday, pushing inland Monday and Tuesday. As the system approaches the region on Sunday, temperatures from Saturday to Sunday will lower around 5 to 10 degrees across all areas. The weather system will also increase winds across the region, with widespread westerly wind gusts 25-45 MPH across the mountains and deserts each afternoon and evening. As the system moves over SoCal, there will be the chance for light rain to occur from the coast to the mountains. The system's moisture profile continues to look limited, so chances for precipitation is near 15-25% for these areas. There may be drizzle/light showers by Monday morning, but the best chance for rain across the region will be on Tuesday as the core of the system passes by. Accumulations look light to none, highest across the coastal slopes of the mountains.

Models start to struggle a bit by the middle and end of next week regarding the weather system mentioned above. Some want to delay the system into Wednesday, others do not. Regardless, after the weather system passes, a weak ridge will move in its place, bringing warmer and drier weather for the end of next week with less wind.

Aviation

302330z. Coast/Valleys, BKN-SCT low clouds with bases 1500-2500 ft MSL have developed along the immediate coast, including KSAN and KCRQ. Low clouds will become more widespread, spreading up the coast towards KSNA by 06Z and filling in much of the coastal basin by 10Z. Low clouds will clear to the coast 16-18Z, with the potential for BKN low clouds to linger along the immediate coast through 21Z.

.Mountains/Deserts, Areas of elevated westerly winds 20-30 kts, with gusts to 40 kts through mountain passes and into adjacent deserts through 10Z Fri. Areas of up/downdrafts and isolated LLWS in lee of mountains.

Marine

No hazardous marine conditions are expected through Tuesday.

Watches, Warnings, Advisories

Ca, None. PZ, None.

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