Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
463 FXUS66 KSGX 231038 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 238 AM PST Sun Nov 23 2025 .SYNOPSIS... Isolated light rain showers ending this morning, then dry for the remainder of the day. A gradual warming is expected through Thanksgiving, with high temperatures returning to above normal by the middle of the week. Weak to moderate Santa Ana winds Tuesday through Thanksgiving, peaking on Wednesday. Another trough of low pressure will bring a 15-35% chance of showers sometime Saturday afternoon into Sunday along with cooler weather. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Morning water vapor imagery shows the center of the upper level low moving into eastern Arizona with northerly flow over Southern CA on the back side of the low. A few lingering showers are drifting into the mountains and deserts with little in the way of accumulating rainfall. These showers will come to an end by late morning as the low continues to move east, with cool but dry weather for the remainder of the day. High temperatures will be a few degrees below normal across the region. A pattern change takes hold Monday through Thanksgiving as an upper level ridge of high pressure moves in from the west and amplifies, bringing gradual warming and finally a decent stretch of dry weather. A series of short waves will move over the ridge well to our north, leaving behind cold air and surface high pressure building over the Great Basin. This will drive breezy Santa Ana winds Tuesday through Thanksgiving, with a peak in strength on Wednesday. The West-WRF chances for a weak to moderate event are now 40% Tuesday, 70% Wednesday, and 50% Thursday. The chances of a moderate event are close to 20% on Wednesday and around 10% on Thursday. The winds will be solely gradient driven and therefore confined to the usual passes/canyons and coastal slopes, where gusts of 35-50 mph are possible. While Relative Humidity will be much lower, the copious amounts of rain we just received over the past week will mitigate the fire weather threat. The main "impact" from these winds will be the additional warming west of the mountains, where high temperatures will reach the upper 70s to low 80s across much of the coastal basin and low deserts on Wednesday and Thursday. Overall high temperatures will be around 5-10 degrees above normal these days. The ridge weakens and progresses eastward on Friday, and with the return of onshore flow, allows for several degrees of cooling west of the mountains and more subtle cooling elsewhere. There is still considerable uncertainty surrounding the track of the digging upper trough next weekend. About 30% of the ensemble members dig the trough far enough southwest to bring precipitation as early as Saturday, the for Sunday 56% of the members have a deep positively tilted trough digging over the Western US, which would be more favorable for precipitation, while the other 44% have an inside track (little to no precipitation). Forecast still carries a 15-35% chance of precipitation spread across Saturday afternoon and Sunday, highest on Sunday when more ensemble members favor precipitation. Otherwise much cooler next weekend with breezy southwest to west winds in the mountains and deserts. && .AVIATION... 231000Z...ISO high-based -SHRA moving from the northeast will end by 12Z this morning. Meanwhile, SCT-BKN clouds based 8-12 kft MSL will clear through this morning. VFR conditions expected area wide through Sunday evening. Coasts/Valleys...Isolated low clouds based 1000-1500 ft MSL will form in areas after 02Z Mon, becoming more widespread if still patchy along coastal and western inland areas after 06Z Mon. 40% chance for CIGs at KSAN/KCRQ by 06Z, KSNA by 10Z. && .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...SS AVIATION/MARINE...CSP