Swell Matrix

Area Forecast Discussion

National Weather Service San Diego CA

128 pm PDT Fri aug 29 2025

Synopsis

Seasonal weather will continue through the weekend with mostly sunny skies expected. Monsoonal moisture will increase again by Tuesday through the end of the week, with increasing chances for storms to return to the mountains and deserts. Other areas will see slightly warmer conditions with highs up to 5 degrees above normal, warmest on Monday and Tuesday.

Discussion

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

There will be continued drying into the weekend with mostly clear skies. Pwat values will continue to lower across the deserts as well. This will contribute to cumulus clouds building across the mountains, but otherwise, most areas should stay dry. The atmosphere continues to dry out over the weekend with PWAT values lowering under one inch across the lower deserts by the weekend. This will diminish any notable chances for storm activity by the weekend with cumulus forming over the mountains each afternoon. High pressure will begin to grow and expand across the region by Sunday into early next week for areas away from the coast. Nbm 50-75th percentile shows highs around 5 degrees above normal for inland areas with heat peaking by Labor Day into Tuesday. Highs will be generally be near 100 to 105 degrees across the Inland Empire, well into the 90s for the OC/SD valleys, and near 110 degrees across the Coachella Valley and Anza-Borrego Desert. This will bring widespread moderate heat risk across the region, where relief from the heat will be more difficult for vulnerable populations and those without cooling methods.

Monsoonal moisture will increase again by Labor Day into the middle of next week, which will lead to a greater chance of shower and thunderstorms across the mountains and deserts. By Tuesday through at least Friday, chances have increased to near 30-45% across these areas. High pressure will weaken somewhat later next week, which will help steer monsoonal flow away from the region, lowering the chances of storms. Other areas will see highs near to slightly above average with dry weather with a subtle cooling trend into the latter half of the week. Coastal areas can expect to see patchy low clouds near the coast each night and morning by next week as well.

Aviation

292000z, VFR through tonight region-wide. Very patchy coastal low clouds based at 800 feet after 10Z Saturday along the SD County coast.

Marine

No hazardous marine conditions are expected through Tuesday.

Watches, Warnings, Advisories

Ca, Beach Hazards Statement from late tonight through Monday evening for Orange County Coastal Areas-San Diego County Coastal Areas.

PZ, None.

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