Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
766 FXUS66 KSGX 140348 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 848 PM PDT Sat Jul 13 2024 .SYNOPSIS... Hot summer weather will continue inland this coming week. Monsoon moisture will bring another chance of thunderstorms Sunday afternoon in the mountains and high desert, with a very slight chance Monday afternoon. The marine layer will continue to bring low clouds and fog to coastal regions and western valleys each night and morning. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... After isolated light showers and sprinkles moved through the region this morning, thunderstorms developed in the mountains and deserts this afternoon. A few grew strong, including a complex that moved through Barstow and later a complex in the southeast corner of San Diego County. These produced gusty winds and localized flooding, especially in Barstow. All storms finished up by 6 pm and skies were clearing. Meanwhile, at the coast, beaches have been treated to more sunshine this afternoon and evening, but low clouds are poised to move ashore later tonight. The monsoon flow will turn just a little, from the southeast flow of today to a southwest flow Sunday. Moisture will decrease slightly on Sunday, but there is another decent chance of thunderstorms in the mountains during the afternoon and evening, and lesser chances in the high desert. Like the storms of today, they could produce strong, gusty winds and localized flooding. Moisture decreases further on Monday, with the slightest of thunderstorm chances for the mountains during the afternoon. Temperatures were down today; Palm Springs` max temp came all the way down to 109, which is exactly normal. The strong high pressure ridge will weaken slightly through Tuesday, providing a respite early next week especially away from the deserts. But the overall pattern of our strong high pressure ridge will persist across the West, promising more very hot summer days and nights later next week. But at this time the heat doesn`t appear quite as oppressive as we had a week ago. The high pressure ridge sets up somewhere in the West again, with some increase in monsoon moisture returning late next week in southeast flow. We`ll keep a close eye on that. Coastal clouds will continue on the same persistent nocturnal schedule and spatial coverage, but may move a little farther inland the next couple nights, maybe even reaching into western inland valleys. Pretty summerlike weather, with variations on inland heat, the marine layer`s coastal clouds, and occasional episodes of monsoon moisture producing a few thunderstorms. && .AVIATION... 140330Z...Coast/Valleys...Areas of low clouds will develop near the coast 05Z-08Z Sun and spread up to 20 miles inland by 12Z Sun with bases 900-1300 ft MSL and tops to 1500 ft MSL. Local VIS 1-3 miles will occur over higher coastal terrain 08Z-16Z Sun, with local terrain obscured. Most areas will clear 15Z-19Z Sun, except local BKN/OVC conditions will linger at the coast. Otherwise, unrestricted VIS and generally SCT clouds at/above 12000 ft MSL will prevail through Sun evening, with areas of low clouds developing again near the coast Sun evening. Mountains/Deserts...There is a slight chance of TSRA Sun afternoon with CB bases around 10000 ft MSL and tops to 40000 ft MSL, along with strong UDDFS and local sfc gusts to 40 kt. Local smoke will occur in the San Gabriel Mountains. Otherwise, unrestricted VIS and generally SCT clouds at/above 12000 ft MSL will prevail thorugh Sun evening. && .MARINE... No hazardous marine conditions are expected through Thursday. && .BEACHES... A SSW swell of 3 feet/18-19 sec/210 deg will arrive Tuesday and continue through Thursday with a gradually lowering period to 15 sec. This will bring elevated surf (sets to 6-7 feet) and high risk of dangerous rip currents to south-facing beaches, mainly in Orange County, Tuesday through Thursday. && .FIRE WEATHER... A Red Flag Warning continues through Sunday for chances of thunderstorms producing dry lightning mainly Sunday afternoon in the mountains and High Desert. For any storm that develops, wetting rain is expected, but lightning can strike away from the rain, causing a fire start in very dry fuels. In addition, strong and erratic winds, possibly reaching 35 to 50 mph, can fan any fire start. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Red Flag Warning until 9 PM PDT Sunday for Riverside County Mountains-Including The San Jacinto Ranger District Of The San Bernardino National Forest-San Bernardino County Mountains-Including The Mountain Top And Front Country Ranger Districts Of The San Bernardino National Forest-San Gorgonio Pass Near Banning-Victor Valley -Apple Valley - Lucerne Valley -Johnson Valley. Excessive Heat Warning until 9 PM PDT Sunday for Coachella Valley-San Diego County Deserts. PZ...None. && $$ PUBLIC/FIRE WEATHER...MM AVIATION/MARINE/BEACHES...Maxwell