Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
556 FXUS66 KSGX 032144 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 144 PM PST Mon Nov 3 2025 .SYNOPSIS... A trough of low pressure will move closer to the West Coast through Wednesday. This will bring a subtle cooling trend with breezier conditions across the mountains and deserts by the middle of the week. High pressure will regain strength by Friday into the weekend, bringing warmer weather. The forecast becomes murkier by the early to middle part of next week as interactions between two pressure systems move closer to the region, one of which that may bring cooler and potentially wetter weather. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Low clouds have faded away off the coast as high clouds begin to thin over Southern California. A trough is beginning to strengthen over the Northern Pacific. This system will continue to move closer to the West Coast into the middle of the week. High pressure to south will maintain its presence as well, keeping the marine layer of similar depth by Tuesday, with a slight deepening by Wednesday. This will garner more low clouds coverage to much of the coastal basin each morning with elevated areas seeing foggy conditions, like in the Inland Empire. Model guidance pushes the area of low pressure to our north on Wednesday and Thursday. This is when the coolest weather will occur over the week with highs within 5 degrees of normal. The strongest part of the system will move through on Wednesday, where the pressure gradient will tighten to produce gusty west winds across the mountains and the deserts. Model guidance indicates wind to be elevated with widespread gusts 35-45 MPH, locally higher in the passes. The area of high pressure to our south will begin to build in once more by Friday into the weekend. This will lead to less wind and warmer weather area wide. The ridge and associated surface high will amplify over the Great Basin by Sunday. This will turn the winds from the east, where weak Santa Ana winds will breeze through the mountain passes and western valleys. NBM shows high temperatures well into the 80s by the weekend across the western valleys; would not be surprised if we see highs near 90 degrees in these regions, including the Inland Empire and San Diego foothills. By Monday into the middle of the week, model ensemble guidance begins to diverge on exactly what pressure systems will impact the region. Models show a large trough forming off the Pacific this weekend, but differences exist whether a part of the system will impact our area or high pressure overhead this weekend will stick around into early next week. Ensemble models show around 25% of members becoming a bit wetter by next Tuesday or Wednesday. As of now, confidence remains low on precipitation occurrence and amounts for next week, but hints of pattern change are definitely in our view as we head toward the middle of the month. && .AVIATION... 032130Z...Coasts/Valleys...VFR currently. Low clouds will redevelop and push back ashore after 02Z, with bases around 500-900 feet MSL. VIS reductions likely begin around 04-06z; 2-5SM for elevated coastal terrain/western valleys and locally 1/4-1SM for inland valleys/Inland Empire in FG. Periods of reduced VIS elsewhere, 4- 6SM, such as KSAN and KSNA, due to HZ/BR. VIS to improve 15-17z Tues morning as bases rise. Scatter out 16-18z. Mountains/Deserts...VFR conditions with gradually decreasing high clouds today and tonight. && .MARINE... No hazardous marine conditions are expected through Friday. && .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...APR AVIATION/MARINE...Westerink