Swell Matrix

Area Forecast Discussion

National Weather Service San Diego CA

451 am PDT Sat apr 1 2023


Today and Sunday will be dry and tranquil. On Monday a cold front will bring cold, windy weather and a chance for light sprinkles and rain showers over and west of the mountains. Behind the departing storm, temperatures will slowly warm Tuesday through Thursday.


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

A weak area of low pressure will move east over Northern Baja California Mexico this, not causing much change to the weather, except to bring temperatures a few degrees warmer as heights climb a bit across the region and a weak East pac upper ridge edges into SoCal, although still cooler than normal for this time of year.

On Sunday a stronger low pressure trough will develop over the Pacific Northwest, then sliding southeast into the Great Basin through Monday night. This storm will bring a slight chance for light showers mainly west of the mountains on Monday, but the more significant impact will be areas of very strong winds. Ec ensemble reforecast tool indicate 80 to 90 percentile strongest winds across our area and up to 95 percentile for areas of Central California with this strong wind event.

The strongest winds will occur Monday afternoon and evening, although wind advisory level winds will become widespread across the mountains and deserts as soon as Sunday night. Therefore we issued a high wind watch for all of the mountain and desert areas beginning late Sunday night and continuing through late Monday night. Additional wind alerts will likely be needed for areas west of the mountains, but the magnitudes are not as likely to reach warning criteria there.

In terms of precipitation, the NBM guidance continues to be very low, but some very light showers or sprinkles will still be likely in the deep marine layer Monday for west of the mountains, although measurable precipitation will only be a few hundredths at best. Have maintained a slight chance for showers with this forecast.

Behind the strong inside slider storm, that will move across Colorado and into Southern Wyoming on Tuesday, northwest flow will keep a dry regime in place for the rest of the week, but also trending cooler than normal as well. Forecast uncertainty increases for next weekend as another cutoff low pressure system could impact SoCal or Northern Baja.


010900z, Patchy low clouds with bases around 1500 feet MSL developing along the coast could have CIG impacts for KSAn and KCRQ at times 10-16Z, but confidence in ceilings at coastal terminals remains low. Any low clouds that do form should clear by 16Z. More widespread low cloud cover is expected tonight into Sunday morning.

Otherwise, FEW-SCT high clouds at/above 20,000 feet MSL through today.


No hazardous marine conditions through Sunday morning. Winds strengthen from the northwest Sunday afternoon and evening with gusts around 20 kt near San Clemente Island. Gale force west- northwest winds and large, rough seas are expected Monday and Tuesday. Gusts of 35-40 kt are possible Monday morning through early Tuesday morning, lowering to 20-25 kt for the remainder of Tuesday into Wednesday morning.


Large, short-period west northwest swells will bring elevated to high surf conditions for Monday into early Tuesday. The highest surf will be on exposed west-facing beaches of southern San Diego County where sets 8-12 feet will be possible.

Watches, Warnings, Advisories

Ca, High Wind Watch from late Sunday night through late Monday night for Apple and Lucerne Valleys-Coachella Valley-Riverside County Mountains-San Bernardino County Mountains-San Diego County Deserts-San Diego County Mountains-San Gorgonio Pass Near Banning.

PZ, None.

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