Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
748 FXUS66 KSGX 132111 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 211 PM PDT Sat Jul 13 2024 .SYNOPSIS... There are chances of thunderstorms in the mountains, locally into the deserts this afternoon through early Sunday evening. Isolated chances of thunderstorms will continue in the mountains on Monday. Hot conditions will continue for the lower deserts into next week. Away from the deserts, temperatures will be near to slightly below average this weekend into the middle of next week. A gradual warming trend is expected for the middle to end of next week. Night and morning coastal low clouds will continue to extend inland into the western valleys into next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... As of 1:30 PM convection is occurring over the high deserts and Coachella Valley. This is in line with the area of maximum cape associated with the moisture plume moving up from the Gulf of California. High resolution model runs continue to show active precipitation, mainly over the higher terrain of San Diego, Riverside, and San Bernardino Counties through this evening and into Sunday evening. Activity will decrease during the overnight hours with some isolated elevated convection remaining possible tonight through Sunday morning. A Red Flag Warning has been issued for dry lightning and gusty erratic thunderstorm winds. This is for the Mountains of San Bernardino County, the mountains of Riverside County, foothills and high deserts. This activity is all due to a large scale ridge of high pressure currently over the Four Corners Region of the American Southwest, and a weak low pressure disturbance that is allowing for a plume of Monsoonal like moisture to into the region. The bulk of the thunderstorm activity is expected to occur this afternoon and evening, with a decrease Sunday, and quieter conditions Monday through the rest of the week ahead. High temperatures for areas away from the deserts will become near to slightly below average for this time of year this weekend through the middle of next week, with continued above average conditions in the deserts. HeatRisk in the High Desert decreases Sunday, with area of major HeatRisk continuing in the low deserts into much of next week. Highs in the low deserts on Sunday will fall a few degrees, but the increase in moisture will result in muggy conditions. Around the middle of next week, temperatures will gradually begin to increase for all areas into next weekend. && .AVIATION... 132025Z...Coast/Valleys...Low clouds with bases 900-1100 ft MSL with tops to 1800 ft MSL over the coastal waters. Low clouds spreading inland again after 14/03Z Sunday with similar bases and tops. Local VIS 1-3SM on higher coastal terrain and portions of the valleys late tonight. Mountains/Deserts...ISOLD-SCT TSRA with SCT-BKN120 with tops to FL300. Brief, heavy rainfall and gusty and erratic winds likely with any storm. Mod up/downdrafts possible near the mountains. Localized VIS of 3SM due to smoke in the San Bernardino Mountains VCNTY of the Vista fire. Gusty west winds possible up to 30 knots around San Gorgonio Pass this afternoon and evening. && .MARINE... No hazardous marine conditions are expected through Thursday. && .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 this evening for Apple and Lucerne Valleys. Excessive Heat Warning until 9 PM PDT Sunday for Coachella Valley-San Diego County Deserts. PZ...None. && $$ PUBLIC...Suk/CO AVIATION/MARINE...Small