Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
954 FXUS66 KSGX 110921 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 221 AM PDT Thu Sep 11 2025 .SYNOPSIS... There will be a gradual warming trend through the middle of next week with high temperatures near the coast warming from the lower 70s today to the mid to upper 70s for next Wednesday, for the Inland Empire warming from the upper 70s to mid 80s today to the 90s for next Wednesday, and for the lower deserts warming from the lower to mid 90s today to the upper 90s to 104 for next Wednesday. The marine layer will become shallower with coastal low clouds covering much of the coast and valleys early this morning, then only reaching the far western valleys at times for next week. Some monsoonal moisture may return for the middle and latter part of next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (Today through Saturday)... A low pressure system will continue to move slowly inland through the western states through Friday and into the Rockies on Saturday with high pressure aloft moving to near the West Coast on Saturday. High temperatures today will warm a few degrees for the mountains and inland valleys with not much change on Friday. There will be additional warming on Saturday of as much as 5 degrees for the mountains, high desert, and inland valleys with Saturday high temperatures ranging from the lower 70s near the coast to the 80s for the Inland Empire with the mid to upper 90s for the lower deserts. A marine layer near 3000 feet deep will gradually decrease in depth for Friday and Saturday. Coastal low clouds will extend inland across most of the coast and valleys early this morning, then into portions of the inland valleys for late tonight into Friday morning, and into the western valleys for late Friday night into Saturday morning. && .LONG TERM (Sunday through Wednesday)... A low pressure system will move inland through the Pacific Northwest on Sunday with only slight warming for southern California on Sunday with continued slow warming for Monday through Wednesday. High temperatures will warm from a few to around 5 degrees below average on Sunday to around 5 degrees above average for the coast and valleys on Wednesday. Wednesday high temperatures will range from the mid to upper 70s near the coast to the 90s for the Inland Empire with the upper 90s to 104 for the lower deserts. The marine layer will become a little shallower with night and morning coastal low clouds extending inland into the far western valleys at times late each night. Some monsoonal moisture may return for the latter half of next week with NBM daily chances for measurable rainfall for Big Bear increasing to 10 percent on Wednesday, 19 percent on Thursday, and 25 percent on Friday. && .AVIATION... 110930Z...Coast/Valleys...Low clouds with varying bases 2000-3000 feet MSL and tops to 3500 feet will continue to cover most of the coastal basin, but more likely SCT clouds near the coast. Clearing will be random and intermittent this morning, with nearly all of the coastal basin scattered out by 19Z. Low clouds will begin to reform in western San Diego County around 23-01Z, and then fill into Orange County and the inland areas after 04Z. Full cloud coverage of the coastal basin not expected, with bases 1800-2500 feet MSL tonight into early Friday. Mountains/Deserts...VFR conditions prevail today and tonight. Westerly winds of 25-30 mph with gusts up to 40 mph 21-08Z today and tonight through mountain passes into adjacent deserts, causing isolated pockets of LLWS and up/downdrafts in lee of mountains. && .MARINE... 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