textproduct: San Diego

SYNOPSIS

Temperatures cool this weekend to near normal, but increasing moisture will keep overnight lows above average. Further warming next week with limited overnight cooling and monsoonal thunderstorms each afternoon in the higher terrain. Coastal flooding will impact beaches late this weekend into early next week as high tides return above 7 feet.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

Mid level water vapor satellite imagery shows high pressure sitting over Southern California, which supplied in the well-above-normal temperatures we've experienced the past few days. Also visible is a deepening low approximately 900 miles off the coast of Central CA, poised to push eastward over the next several days. As it propagates, the aforementioned high will be kicked to the northeast, settling over the High Plains region by early to mid week. Temperatures will cool over the weekend a bit closer to near normal with a slightly deeper marine layer as the high begins to push out of the region. As it leaves, PW values will be rising as sub tropical moisture is able to sneak up into the area. With the elevated moisture, overnight lows will struggle to cool and HeatRisk will prevail for interior areas with limited overnight recovery.

By late weekend and early next week, the high will position further northeast as the ample mid and low level moisture that transports into SoCal becomes sufficient enough for monsoonal thunderstorms to develop over the higher terrain. Any thunderstorms may be accompanied by gusty and erratic winds, lightning, and brief, heavy rainfall. The thunderstorm threat will exist each afternoon for much of next week, with around a 10-15% chance for a storm or two to make it off the mountains and meander into the valleys or deserts. Temperatures will remain fairly average into Monday, but as mentioned before, the elevated overnight lows will help to maintain moderate HeatRisk for many interior spots. As the week progresses, additional warming will be observed and Major HeatRisk will return around the middle of next week with very warm overnight lows, likely around 5-7 degrees above normal. For the coast, astronomical high tides of 7-7.5 feet will allow for a high rip current risk and waves will make it further up the beach than typical, potentially flooding some low- lying spots. Never turn your back to the ocean! Additional information can be found in the Beaches Discussion below.

The main concern this week is that the heat will drive people both to the mountains and oceans in attempt to escape to cooler weather, but the thunderstorm and coastal flooding risk will make certain activities dangerous. While tides will fall by early week, models continue to push monsoonal moisture up to the area through at least Friday, with storm chances each day through then. Heat looks to peak Wednesday before slightly cooler weather Thursday/Friday, although the pattern this far out is still quite uncertain.

Mountains/Deserts

VFR conditions through the TAF period. Periods of SCT-BKN upper level clouds AOA 10k ft.

MARINE

No hazardous marine conditions are expected through Thursday.

BEACHES

Astronomical high tides peaking at 7.0-7.5 ft are expected each day July 12-14. Higher than normal tides combined with a modest south swell (3 ft swell at 13-15 seconds from 190 degrees) generating surf of 3-5 ft for south-facing beaches will result in areas of coastal flooding in low lying areas, boardwalks, beach parking lots, and beach adjacent streets during evening high tides. Highest tides each day will generally occur between 8 and 10 PM each evening. A Beach Hazards Statement has been issued for this hazard from Sunday afternoon through Tuesday evening and contains more information.

SGX WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement from Sunday morning through Tuesday evening for Orange County Coastal Areas-San Diego County Coastal Areas.

Heat Advisory until 8 PM PDT this evening for Riverside County Mountains-San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Mountains.

Extreme Heat Warning until 8 PM PDT this evening for Coachella Valley-San Diego County Deserts-San Gorgonio Pass near Banning.

PZ...None.