Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
716 FXUS66 KSGX 240509 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 909 PM PST Sun Nov 23 2025 .SYNOPSIS... A gradual warming is expected through Thursday, with high temperatures returning to above normal by the middle of the week. Weak to moderate Santa Ana winds are expected Tuesday through Thursday, with the strongest winds expected on Wednesday. A trough of low pressure will bring cooler weather and a chance of showers for the upcoming weekend. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Satellite at 9 PM was showing patchy low clouds developing along the immediate coast. Low clouds are expected to become more widespread overnight, potentially reaching into portions of the western valleys. Low cloud coverage will become less likely to develop Tuesday through Thursday when the pressure gradient becomes offshore. Highs Monday are expected to be a few degrees warmer than today for inland locations with a degree or two of cooling along the coast. From previous discussion issued 2 PM November 23... A pattern change will see the western US become dominated by a building ridge of high pressure aloft at least through Thanksgiving, along with periods of offshore flow as sfc high pressure moves into the Great Basin. This will bring dry conditions and a warming trend through midweek. The offshore pressure gradients will bring Santa Ana winds for Tuesday through Thanksgiving. The winds will be strongest on Wednesday with northeast to east winds gusting 35-50 mph in the wind-prone areas of the passes/canyons and coastal slopes. Humidities in the inland valleys will drop into the high teens to low 20% range but the fire danger will be mitigated by the rains over the last week. It looks like Wed and Thu will be the warmest days, with daytime high temperatures in the low deserts, valleys and coastal areas reaching the 70s to low 80s. High temperatures could be as much as 11-14 degrees above seasonal averages in the inland valleys. For Friday into next weekend...The ridge of high pressure will be weakened and displaced by an extensive area of low pressure. This will bring a return of cooler, unsettled weather with onshore flow, higher humidity and chances for widespread precipitation next Sat and Sun. There is still considerable uncertainty surrounding the track and timing of multiple shortwave troughs but at this time, about 55% of ensemble members show precipitation sometime between Sat and Sun. && .AVIATION... 240400Z...Coasts/Valleys...SCT low clouds based 1000-1500 ft MSL over coastal waters will spread into coastal San Diego County within the next few hours. Thereafter, clouds will expand to Orange County and likely push into western valleys from 06-09Z. 30-40% chance clouds reach eastern valleys and into the Inland Empire (including KONT). Bases may lower some overnight (700-1200ft MSL) creating minor vis reductions (1-5SM) for elevated valleys. Clouds scatter to the coast 16-18Z. Low clouds return to coastal areas 03-06Z Tue with lower bases allowing for minor vis reductions along higher coastal terrain. Less inland extent than tonight with clouds remaining mostly confined to within 10 miles of the coastline. Mountains/Deserts...VFR conditions expected through Monday evening. && .MARINE... No hazardous marine conditions are expected through Thursday. && .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...CO/PG AVIATION/MARINE...KW