textproduct: San Diego

SYNOPSIS

The peak of the heat will last through Thursday, with conditions not as hot by Friday into early next week. Elevated heat risk will remain through much of next week. Daily chances for monsoon thunderstorms will occur through the weekend, highest on Thursday and Friday in the mountains and locally into the deserts. Temperatures stick near average for the first half of next week with minimal chances for thunderstorms in the mountains.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

Cumulus clouds are beginning to bubble over the mountains via satellite and out our weather windows at the office as we near the lunch hour. The chance is there for a few showers and weak storms to develop over the highest terrain along peninsular ranges from the Mexican border to the Big Bear Lake region later this afternoon. PWAT values are not as high as yesterday with less instability, but we'll have to see what Mother Nature has in store for us. Temperatures will reach their peak this afternoon, where moderate heat risk will be present for many inland, locally major for far inland valleys and the lower deserts. Temperatures will lower a few degrees by Thursday, whilst heat alerts remain in effect until Thursday evening. Highs will top our near to just over 100 degrees for inland valleys from Ramona to Ontario. Even the mountains will be warm with highs in the 80s and 90s.

Subtle increases in moisture are seen in model guidance by Thursday and Friday, leading to an increased chance of showers and thunderstorms across the mountain areas, locally into the deserts. A little more hesitant with this forecast due to lack of instability seen in the latest guidance, so confidence is on the lower end. We will continue to be right on the edge of the storm activity through Saturday with chances near 15-40% each afternoon and early evening in the mountains, and north of Big Bear in the high desert.

By Sunday into the first part of next week, high pressure over the Rockies shifts east into the Southern Plains. This will bring clockwise monsoonal flow around the high to shift eastward with it, moving more into Arizona and New Mexico. Moisture looks to remain elevated for our area though, so cumulus clouds forming over the mountains each day is a good bet, but there is increasing confidence that these will have a tough time producing any rainfall. Temperatures will remain near average each day with marine layer clouds blanketing areas up to 20 miles inland each night and morning.

Mountains/Deserts

SCT Cu based around 12,000ft MSL along with ISO TSRA over mountain ridges this afternoon and again Thursday afternoon. Otherwise, FEW-SCT high clouds AOA 15,000 ft and VFR.

MARINE

No hazardous marine conditions are expected through Saturday.

BEACHES

Astronomical high tides will peak again around 7.0 feet this evening. High tides combine with a modest south swell (2 ft swell at 13-15 seconds from 190 degrees) to generate surf of 3-5 ft for south- facing beaches and 2-4 ft elsewhere. This will produce areas of coastal flooding in low lying areas, boardwalks, beach parking lots, and beach adjacent streets during evening high tides. A Beach Hazards Statement remains in effect through Wednesday evening and contains further details. There will be an increased risk of rip currents through Wednesday.

High amplitude southerly swell (4-5 ft) will arrive this weekend, bringing elevated surf and strong rip currents for Sunday and into early next week. Highest surf will be along south and southwest- facing beaches.

SKYWARN

Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions.

SGX WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement through this evening for Orange County Coastal Areas-San Diego County Coastal Areas.

Heat Advisory until 8 PM PDT Thursday for Orange County Coastal Areas-San Diego County Coastal Areas.

Extreme Heat Warning until 8 PM PDT Thursday for Coachella Valley-Orange County Inland Areas-Riverside County Mountains-San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Deserts-San Diego County Mountains-San Diego County Valleys-San Gorgonio Pass near Banning-Santa Ana Mountains and Foothills.

PZ...None.