Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
599 FXUS66 KSGX 020935 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 235 AM PDT Thu Oct 2 2025 .SYNOPSIS... Today will be a few degrees warmer with cooling for Friday into Saturday as a low pressure system moves inland into California and Nevada. There will be stronger southwest to west winds for the mountains and deserts on Friday with gusts to 35 to 45 mph along the east slopes of the mountains. The marine layer will deepen for Friday into early Saturday with coastal low clouds spreading into portions of the inland valleys for Friday night. Low pressure from the north will spread cooling of a few to around 5 degrees inland for Sunday and Monday. Then a few degrees warmer for Tuesday and another 5 degrees warmer for Wednesday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (Today through Saturday)... High pressure to the east will bring a few more degrees of warming today. This will be followed by cooling for Friday into Saturday as a low pressure system moves inland into California and Nevada. On Friday, there will be stronger onshore flow on Friday with stronger southwest to west winds for the mountains and deserts with gusts to 35 to 45 mph along the east slopes of the mountains. The marine layer is around 1200 to 1400 feet deep with a weak inversion. Satellite imagery shows only patchy coverage of coastal low clouds. Patchy night and morning low clouds will increase in coverage and spread farther inland for Friday into early Saturday as the marine layer deepens. The low clouds for late Friday night into early Saturday will spread into portions of the inland valleys and possibly onto the lower coastal mountain slopes. && .LONG TERM (Sunday through Wednesday)... Low pressure from the north will spread cooling of a few to around 5 degrees inland for Sunday and Monday with high temperatures on Monday 5 to 10 degrees below average for inland areas. High temperatures on Monday will range from around 70 near the coast to the mid 70s to around 80 for the Inland Empire with the lower deserts around 90. This will be followed by warming for Tuesday and Wednesday with Wednesday high temperatures still a few degrees below average, ranging from around 70 near the coast to the lower to mid 80s for the Inland Empire with the lower 90s for the lower deserts. && .AVIATION... 020930Z....Coasts/Valleys...Variable low clouds based 1000-1500 feet MSL will gradually increase through 14Z. Local vis reduced 1-5SM on higher coastal terrain. Scatter out expected by 16Z. Low clouds develop after 03Z coastal areas and after 08Z inland tonight into Friday. Bases should be around 1500 feet MSL, rising over 2000 feet MSL early Friday, filling much of the coastal basin. Mountains/Deserts...Mostly clear and VFR conditions today and tonight. && .MARINE... Northwest winds Friday afternoon and evening over the outer waters near San Clemente Island could lead to hazardous conditions for small craft. Otherwise, no hazardous marine conditions are expected through Monday. && .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...MM