Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
463 FXUS66 KSGX 100425 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 825 PM PST Tue Dec 9 2025 .SYNOPSIS... Warm and dry conditions with periods of weak Santa Ana winds this week. Above average temperatures expected into next week, with the most significant departure from normal expected today through Thursday. Mostly clear skies are expected through at least Thursday, with low clouds and fog returning to coastal areas as early as Friday or Saturday morning. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Evening update... Skies remain clear this evening under weak offshore flow. Several high temperature records were broken today, the warmest of which was Escondido, which tied their daily of 86 degrees. The most impressive was Big Bear, which after a low of 27 degrees this morning made it up to 72 degrees this afternoon, breaking their previous daily high record of 65 degrees. See LAXRERSGX for a complete list of records. Weak offshore flow will continue into Wednesday afternoon. Peak gusts of around 25-35 mph is expected through the typical wind-prone passes, canyons, and foothills. The upper level ridge of high pressure over the East Pac will continue to shift eastward on Wednesday bringing additional warming across the region with highs as much as 15-20 degrees above normal in the valleys and foothills and around 10-15 degrees above normal elsewhere. Little change in high temperatures on for Thursday for the mountains and deserts, but weakening offshore flow will be overtaken by the sea breeze Thursday afternoon, helping spread a little cooling into the coastal areas and valleys. The upper high then weakens on Friday, bringing minor cooling to the entire region on Friday. Previous discussion... Skies are expected to remain mostly clear through Thursday. Chances of low clouds and fog returning to the coast begin to increase Friday with higher chances over the weekend. High resolution guidance is showing the development of a coastal eddy Thursday night into Friday, which would increase the chances of low clouds and fog returning to coastal areas. The first night or two that marine layer low clouds and fog return, the fog has the potential to be dense especially as ridging aloft remains over the area. Highs for the weekend into early next week will remain above average, but not quite as warm as this week. Highs along the coast through Monday will be about 5 degrees above average and 8 to 12 degrees above average for inland areas. For the early to middle part of next week there starts to become some uncertainty in the upper level pattern. By next Tuesday, 65% of ensemble clusters are showing the ridge continuing over the West Coast, with 20% showing the ridge weakening due to an incoming trough, and 15% showing the ridge present but over the Eastern Pacific. && .AVIATION... 100400Z...Clear skies with VFR conditions will continue through the TAF period at all sites. Breezy northeast winds in the foothills and locally into the adjacent valleys with gusts up to 25-30 kts will be possible through 18Z Wednesday with winds beginning to trend down after 20Z. && .MARINE...No hazardous marine conditions are anticipated through Sunday. && .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/CO AVIATION/MARINE...Westerink