Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
651 FXUS66 KSGX 032040 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 140 PM PDT Sun Aug 3 2025 .SYNOPSIS... Near normal temperatures will occur through Tuesday. High pressure will strengthen over the region Wednesday through Friday, which will bring a warming trend across the area 5 to 10 degrees above average. The marine layer will become shallower by the middle of the week as well, keeping clouds and fog confined closer to the coast. There are increasing chances to see the high weaken by next weekend, bringing temperatures closer to average. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Afternoon satellite shows low clouds offshore with smoke aloft from the Gifford Fire near San Luis Obispo. Hazy skies will continue through at least tomorrow as the fire burns. The marine layer may be slightly thinner this evening, where low clouds will stay closer to the coast and western valleys. Patchy fog will occur once again for elevated terrain into some valleys by dawn. High pressure stays anchored over El Paso, TX through Tuesday, which will lead to little change in temperatures. By Wednesday through Friday, high pressure over New Mexico will amplify and expand westward. This will bring greater warming to the region as 850mb climb near 30C. Models depict the greatest warming to be on Thursday as the high peaks in strength. The low deserts will see moderate to high (40-80%) chances to see highs exceed 115 degrees. Chances are about the same for the Inland Empire and high deserts to reach 100 degrees, along with some inland valleys of San Diego County. This will create moderate HeatRisk conditions for inland valleys and mountain areas, and high HeatRisk for the lower deserts. If you must be outside, make sure to take breaks, drink plenty of water, and find areas of air conditioning to stay cool. Slight increases in PWAT`s are seen by this period as well, but any chance of monsoonal thunderstorms continues to be below 10 percent for the mountains and deserts. Cluster analysis shows some members showing a weakening high over the Southwest, as a trough to the north introduces some lowering heights and cooler air. If this occurs, greater onshore flow and cooling would occur across the region, lowering temperatures to where they are today near average. The high may take a bit longer to weaken into the weekend though, which could delay the cooler weather pattern by a day or two. && .AVIATION... 032000Z....Coasts/Western Valleys...Intermittent high clouds AOA 25k ft as well as smoke aloft from the Gifford Fire to our distant northwest today and Monday. No surface vis issues from smoke are expected. Low clouds based 900-1200 ft MSL redevelop this evening and begin to slowly move inland up to about 15 miles after 4/05Z. Vis reduced to 1-5SM over higher coastal terrain and elevated western valleys. Clouds clearing again 04/15-17Z. .Inland Valleys/Mountains/Deserts...Intermittent high clouds AOA 20k ft as well as smoke aloft from the Gifford Fire to our distant northwest today and Monday. No surface vis issues from smoke are expected, and VFR conditions expected through Monday afternoon. && .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...CSP