Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
134 FXUS66 KSGX 151009 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 309 AM PDT Tue Jul 15 2025 .SYNOPSIS... High pressure will weaken as a weak upper level low pressure system off the central coast of Baja moves into northern Baja Thursday night and into southern California on Friday. There will be cooling for today and Wednesday with a chance of afternoon showers and thunderstorms, mainly for the mountains and mainly on Thursday and Friday with decreasing chances on Saturday afternoon. Then drier and a little warmer inland for Sunday into early next week. Night and morning coastal low clouds will spread into the western valleys late each night. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (Today through Thursday)... High pressure will weaken across southern California while a low pressure system centered just off the coast of central Baja moves into northern Baja late Thursday. There will be cooling for today and Wednesday with the greatest cooling for today in the mountains with a few degrees of cooling for most areas on Thursday. Monsoonal moisture will increase on Thursday with a slight chance of showers and thunderstorms on Thursday afternoon, mainly for the mountains. The marine layer will remain around 2000 feet deep with night and morning coastal low clouds spreading into the western valleys late each night. && .LONG TERM (Friday through Monday)... The center of upper level low pressure will move northward into the vicinity of southern California on Friday. NBM chances for afternoon thunder and measurable rainfall are greater on Friday than Thursday and greatest for the San Bernardino Mountains on both days. Convection on Friday afternoon will not necessarily be tied to terrain with some elevated convection on the north side of the upper low moving toward the west and southwest in the circulation around the upper low. However, just where that might occur in southern California on Friday afternoon is less certain given the spread in the track of the center of the upper low. Moisture will be decreasing for Saturday and Sunday with lesser chances for afternoon showers or thunderstorms on Saturday and mostly for the mountains with a less than 10 percent chance for any showers and thunderstorms for the mountains on Sunday afternoon. Drying will continue into early next week with not much change in high temperatures for the coast and valleys with the deserts a few to around 5 degrees warmer. && .AVIATION... 150900Z....Coast/Valleys...Low clouds based 1000-1500 ft MSL with tops to 1800 ft MSL have moved 20-25 miles inland, and will progress into the southern and western IE including VCTY KONT around 11Z, with vis restrictions 4-6 SM through 16Z. Clouds scatter inland 16- 17Z and near the coast 17-19Z, with slightly better chances for coastal clearing after 19Z (65% chance at KSAN and KCRQ, higher at KSNA). Clouds with similar bases will push inland to a similar extent after 16/00Z. Mountains/Deserts...Mostly clear skies with unrestricted VIS through late tonight. && .MARINE... No hazardous marine conditions expected through Saturday. && .BEACHES... A moderate period south-southwesterly swell (2-3 feet at 15-17 seconds) will generate elevated surf and a high risk of rip currents Wednesday and Thursday. Surf of 3-5 feet expected with sets to 6 feet possible, primarily on southerly facing beaches. Swell and surf will begin to lower on Friday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...17 AVIATION/MARINE/BEACHES...CSP