FXUS66 KSGX 250354 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 854 PM PDT Fri Oct 24 2025 .SYNOPSIS... Cooler this weekend with breezy west winds on Sunday. The marine layer will deepen, with low clouds and fog reaching into portions of the western valleys. Periods of offshore flow will bring warmer and drier weather with a shallower marine layer next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Evening update... Low clouds have returned much earlier this evening, already spreading into the far western valleys of San Diego County. Clouds will spread northward into Orange County tonight as a weak coastal eddy redevelops. The 00Z KNKX sounding shows the marine inversion based near 1400 ft MSL, so fog is much less of a concern tonight. Elsehwere skies will remain clear tonight. No changes to the forecast this evening. Previous discussion... A low pressure system moving inland to the north Saturday will displace the ridge currently over Southern California to the east. That pattern shift will bring cooler weather to Southern California. Highs this weekend will be a few degrees below average west of the mountains, but remain near average in the deserts. Zonal flow aloft and stronger onshore flow at the surface will produce gusty westerly winds, mainly for the mountains and deserts. Westerly winds with peak gusts 35 to 45 mph are expected each afternoon and evening with the strongest winds through wind prone passes. There is fairly good agreement that a ridge dominated pattern will set up over the Southwestern United States. High pressure aloft and periods of weak offshore flow will bring warmer conditions through next week. Wednesday will likely be the peak of the heat, with the ridge expected to weaken slightly as a minor shortwave trough moving inland to the north for the end of next week. Highs Wednesday will be up to 15 degrees above average for the inland valleys. The ridge- y pattern will also reduce the depth of the marine layer and restrict any low clouds/fog to the coastal areas. && .AVIATION... 250300Z...Coast and western Valleys...Low clouds based 700-1000 ft MSL have developed along the coast and will continue to move inland 10-15 miles through 16Z. Reduced VIS to around 1-5SM are expected where clouds meet terrain and locally in inland valleys near sunrise. 40% chance for VIS reductions below 2SM for KCRQ. VIS improves and low clouds scatter 16-18z. Low clouds around 1,500- 2,000 ft MSL will move in again after 03Z Sunday. Inland Valleys/Mountains/Deserts...VFR conditions expected through the TAF period. SCT high clouds around 25,000 ft MSL will move in from the north after 16z Sat with SCT mid level clouds around 10,000 ft moving in from the north after 18Z. && .MARINE... No hazardous marine conditions are expected through Tuesday. && .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...SS AVIATION/MARINE...Villafane