Swell Matrix

Area Forecast Discussion

National Weather Service San Diego CA

536 pm PDT Fri jul 17 2026

Synopsis

Temperatures cooling for inland areas today will be similar into much of next week. Chances of thunderstorms are elevated once again across the mountains this afternoon. Storm chances begin to decrease with minor chances expected for highest ridges in the San Bernardino and Riverside County mountains each afternoon into the first half of next week. Confidence lowers for increasing chances later in the week. Low clouds will continue to cover coastal areas each night and morning into the next week as well.

Discussion

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

, UPDATED AVIATION DISCUSSION,

, UPDATED BEACHES DISCUSSION,

Satellite imagery shoes shows mid-level clouds over parts of SoCal and further to the east, with drying trends noticed over northern portions of the mountains. Clearing this morning will create a better environment for thunderstorm activity as we head into the afternoon. Comparing yesterday to today, the environment is seemingly a bit less primed with less instability, though PWATs are still near 1.5", plenty moist enough. Latest hi-res model guidance again favors the Riverside and San Diego County mountains to receive the greatest rainfall, locally near 0.50"-1" per hour rates, for later this afternoon. Storms will begin to weaken by early evening. Otherwise, temperatures today will feel not as hot as yesterday. High temperatures will be closer to average with highs in the 90s across the IE and high desert, and 70s/80s for the coast, western valleys and mountains. Elevated humidity with overnight lows near to slightly above average will remain though.

Moisture around an area of high pressure over the Intermountain West decreases and pushes further east by the weekend. Moisture will still remain in place, so chances do remain over the higher mountains of SBD/RIV Counties on Saturday. The atmosphere looks to dry out a bit further by Sunday through Tuesday, bringing chances near 10-15% along the eastern parts of the SBD Mts. Other than this, the overall weather pattern will remain relatively unchanged with temperatures near average with mostly clear conditions.

The forecast in monsoonal moisture becomes less certain by the latter half of next week. Models still continue to be split on the placement of the area of high pressure, which will dictate where and how much monsoonal moisture we are able to receive. This will also dictate if we stay near normal or warm slightly above normal.

Aviation

180030z. Coast/Valleys, Looking at multiple cloud decks along the coast with bases around 1,500ft MSL in southern San Diego and bases around 4,000ft MSL in Orange County. Higher mid-level clouds have been moving through around 15,000-20,000ft MSL. A few low clouds will continue to move in along the coast through the period, increasing in coverage in SD after 05-06Z, and spreading north into OC after 08-09Z. Low clouds will be patchy with bases between 900- 1,200ft MSL. Low clouds clear 16-17Z.

.Mountains/Deserts, VFR conditions expected through the period with SCT mid-level clouds AOA 15,000ft MSL forming near the mountains. SCT Cu based 10-12 kft MSL and ISO-SCT SHRA/TSRA may develop over the Riverside and San Bernardino mtns after 18Z, most likely 20Z, through 01Z Sunday. Any storms that develop may produce lightning, gusty winds, and vis reductions.

Marine

No hazardous marine conditions are expected through Wednesday.

Beaches

High amplitude southerly swell (4-5 ft with a period of 12-13 seconds) will build Sunday, bringing elevated to high surf and strong rip and longshore currents for Sunday through at least Tuesday. Highest surf, up to 7-9 ft, will be along south and southwest-facing beaches. Further details can be found in the High Surf Advisory. Surf falls a bit after Tuesday and into Wednesday before another stronger southerly swell (3-4 ft with a period of 15 seconds) brings another round of elevated surf for the end of the week and into the early weekend. From Sunday onward, there will be a high rip current risk.

Watches, Warnings, Advisories

Ca, High Surf Advisory from 5 PM Sunday to 11 PM PDT Tuesday for Orange County Coastal Areas-San Diego County Coastal Areas.

PZ, None.

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