Swell Matrix

Area Forecast Discussion

National Weather Service San Diego CA

1035 am PDT Tue aug 18 2026

Synopsis

High pressure to the east will slowly strengthen into the middle of this week with high temperatures for Wednesday and Thursday around 5 degrees above average for inland areas. High temperatures will cool slightly for Friday into early next week to within a few degrees of average for next Monday. Night and morning coastal low clouds will continue into next week. There is also a slight chance of afternoon showers and thunderstorms for the mountains and deserts on Thursday and Friday.

Discussion

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

, UPDATED AVIATION DISCUSSION,

Short Term

(today through Thursday), High temperatures will continue to warm a few degrees for today and Wednesday with not much change for Thursday. High temperatures for Wednesday and Thursday will be around 5 degrees above average for inland areas with high temperatures ranging from the mid 70s to lower 80s near the coast to the mid 90s to 105 for the Inland Empire with around 110 for the lower deserts.

Monsoonal moisture will continue to gradually decrease through tonight, then increase again for late Wednesday into Thursday. A slight chance of afternoon showers and thunderstorms for the mountains and deserts will return for Thursday.

Long Term

(Friday through Monday), Higher precipitable water values will continue through Friday though slightly below the peak on Thursday. A slight chance for afternoon showers and thunderstorms for the mountains and deserts will continue on Friday with decreasing chances for the weekend into early next week.

High temperatures won't change much or cool slightly for the weekend into early next week, though with increasing spread in the high temperature guidance for next week. High temperatures on Friday will be a few to around 5 degrees above average, ranging from the mid 70s to lower 80s near the coast to the mid 90s to 102 for the Inland Empire with 106 to 110 for the lower deserts.

For Monday of next week, high temperatures will be within a few degrees of average, ranging from the mid 70s to lower 80s near the coast to the 90s to around 100 for the Inland Empire with 104 to 108 for the lower deserts.

Aviation

181740z. Coast, SCT-BKN high clouds through the TAF period. Patchy BKN low clouds impacting TAF sites intermittently between 10- 15Z Wed near 700-1000 ft MSL with moderate to high confidence. Best chance for cigs will again be in San Diego County. Complete scatter out between 15-17Z.

Otherwise, VFR prevails with SCT-BKN high clouds AOA 15000 feet MSL through the period.

Marine

No hazardous marine conditions are expected through Saturday.

Watches, Warnings, Advisories

Ca, None. PZ, None.

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