Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
042 FXUS66 KSGX 111659 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 859 AM PST Thu Dec 11 2025 .SYNOPSIS... Weakening offshore flow will transition to weak onshore flow with slow deepening of the marine layer through the weekend with a greater return of low clouds and fog to coastal areas for the weekend. Gradual cooling will spread inland through the weekend, but with weekend high temperatures still as much as 15 to 20 degrees above average for portions of the inland valleys and lower coastal slopes of the mountains. There will be slight warming on Monday followed by slight cooling for Tuesday and Wednesday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Morning Update... No change from previous update. Weak offshore winds have kept the marine layer largely offshore with clear skies and abundant sunshine expected today. From previous discussion... .SHORT TERM (Today through Saturday)... High pressure aloft will slowly weaken into the weekend with weakening offshore lower-level flow becoming weakly onshore with slow deepening of the marine layer for Friday into the weekend. Early this morning, satellite imagery shows low clouds and fog remain well off the coast and beyond the offshore islands. Some patchy low clouds and locally dense fog could return near the coast tonight into Friday morning. However, increasing coverage and greater spread into coastal areas is more likely for Friday night into Saturday morning. Gradual cooling will spread inland for today into the weekend with Saturday high temperatures still as much as 15 to 20 degrees above average for portions of the inland valleys and lower coastal slopes of the mountains. High temperatures on Saturday will range from around 70 near the coast to around 80 for the Inland Empire with the lower to mid 80s for the lower deserts. && .LONG TERM (Sunday through Wednesday)... Not much change in high temperatures for Sunday. High temperatures may warm slightly on Monday with weak offshore lower- level flow, then cool slightly for Tuesday and Wednesday. Night and morning low clouds and fog will become patchier and not extend as far inland into coastal areas for the early and middle part of next week. && .AVIATION... 111630Z...Clear skies and VFR conditions at all sites through 02Z this evening. Chances for Patchy fog and low cloud development from the coast up to 15 SM inland will increase after 03Z for Orange County and after 05Z for San Diego County. Ceilings around 100-500 ft and visibilities less than 1 SM will be possible through 18Z. && .MARINE... There is a 30-60% chance for fog development this evening through Friday morning. Should fog develop, visibilities below 1 nautical mile will be possible. Otherwise, no hazardous marine conditions are expected today through Monday. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...Munyan AVIATION/MARINE...Villafane