Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
250 FXUS66 KSGX 041132 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 332 AM PST Tue Nov 4 2025 .SYNOPSIS... The marine layer will continue to deepen through tonight with patchy drizzle early this morning for the coast and western valleys with a slight chance of light showers for late tonight for the coast waters inland into coastal Orange County. It will be cooler on Wednesday and breezy in the mountains and deserts, then dry and warmer for the Friday through the weekend. A low pressure system developing well off the California coast early next week could bring some precipitation by the middle of next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (Today through Thursday)... The marine layer is slowly deepening and is around 1200 to 1500 feet deep with widespread low clouds over the coastal waters extending inland into the western valleys. There have been some reports of 0.01 inch of rainfall from patchy drizzle, mainly for inland Orange County and for inland coastal areas and the western valleys in San Diego County. For tonight and Wednesday, a low pressure system moving inland to the north will strengthen the onshore flow across southern California and deepen the marine layer. Low clouds for late tonight will spread into portions of the inland valleys with faster clearing for San Diego County on Wednesday morning. The HREF shows some light showers developing late tonight across the southern California coastal waters, spreading locally inland near the coast for Orange County northward. There will be stronger and gusty southwest to west winds for the mountains and deserts for Wednesday afternoon and evening with gusts to 25 to 35 mph along and below the desert slopes of the mountains with gusts to around 45 mph in the northern Coachella Valley below the San Gorgonio Pass. High temperatures today will be slightly cooler, then as much as 4 to 8 degrees cooler on Wednesday for the valleys. High temperatures on Wednesday will range from the mid to upper 60s near the coast to the lower to mid 70s for the valleys with the lower deserts in the mid to upper 80s. On Thursday, the coast and valleys will begin to warm slightly while the mountains and deserts continue to cool slightly. && .LONG TERM (Friday through Monday)... High pressure aloft will strengthen across California for the weekend. The greatest warming is expected on Friday for the inland valleys onto the lower coastal mountain slopes as the marine layer becomes shallower. There will be slight additional warming during the weekend. Sunday high temperatures will be mostly 5 to 10 degrees above average for inland areas, ranging from the lower to mid 70s near the coast to the 80s for the Inland Empire with the lower deserts around 90. A low pressure system developing well off the California coast early next week could bring some precipitation by the middle of next week. NBM chances for measurable rainfall remain below 10 percent through Tuesday, then increase to around 20 percent on Wednesday and 50 percent on Thursday. For Wednesday and Thursday combined, NBM has around a 20 percent chance for one inch or more of rainfall for Big Bear with snow levels falling from around 8500 feet on Thursday to 7500 feet on Friday. && .AVIATION... 041030Z...Coasts/Valleys...Low clouds based at 800-1200 feet MSL with tops to 1500 feet will continue to march into parts of the inland valleys this morning. Vis 0-5SM over higher coastal terrain and in inland valleys. Scatter out is expected 16-18Z. Low clouds with higher bases around 1200-1800 feet MSL will push ashore 00-03Z, and spread into most of the coastal basin overnight into Wednesday. Vis reductions 0-5SM for inland valleys and coastal hills. Mountains/Deserts...Mostly clear and VFR conditions today and tonight. && .MARINE... No hazardous marine conditions are expected through Saturday. && .BEACHES... Long period west-northwest swell will arrive Thursday, peak Thursday night, and gradually diminish Friday. Surf of 4-5 feet is expected, highest on west-facing beaches. This will present a high rip current risk. && .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...MM