Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
786 FXUS66 KSGX 120428 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 928 PM PDT Wed Jun 11 2025 .SYNOPSIS... Seasonal weather will continue through into the end of the week with a persistent marine layer. High pressure will expand over the desert southwest by Sunday, leading to slight warming for inland areas. A weak troughing pattern will take hold by early next week, where highs will be closer to average. Dry weather continues for the foreseeable future. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... This evening...The marine layer is about 1700 ft deep and already low clouds have spread about 15 miles inland. Sfc pressure gradients remain onshore and high resolution models show the low clouds spreading farther inland by sunrise, with reduced visibility in fog on the higher coastal terrain. From previous discussion... Minor day to day changes will occur through Saturday as high pressure is kept to the south by a trough that persists along the coast of the Pacific Northwest. The marine layer will maintain its depth over the next few days with clouds overnight into the morning across the valleys, with less clear conditions at the coast. Patchy fog will occur mainly across the valleys and elevated coastal terrain. NBM was used for the forecast with highs in the 90s and lower 100s across the Inland Empire and desert regions. High pressure to our south will expand farther across the southwestern part of the country by the weekend. This will lead to warmer temperatures away from the coast, where highs will go around 5 to 10 degrees above average. High temperatures will likely go over 110 degrees across parts of the lower deserts by Sunday with a 5-25% chance of highs going above 115 degrees across the Coachella Valley. Confidence is low to moderate in seeing temperatures approach 100 degrees across parts of the Inland Empire as well as highs in the lower 90s for other western valleys. Rising heights will also allow the marine layer to be suppressed some, so chances for low clouds in the western valleys will lower. A subtle troughing pattern will take hold by early next week, though models do struggle a bit with how deep this will be. The deeper the trough, the greater the cooling and deeper marine layer. For now, the NBM forecast has been used to show a slow cooling pattern by early next week with continued dry weather. && .AVIATION... 110300Z....Coast/Valleys...Low clouds based around 1000-1500 feet MSL with tops to around 2000 feet will continue to move inland throughout the evening, with bases lowering to 200-800 ft MSL and reduced vis 0-5 SM inland, and over higher coastal terrain between these levels. Inland areas scatter out again 16-17Z Thu, 18-20Z for coastal areas, with only intermittent clearing along the immediate coast again. 20% chance for KCRQ and KSAN to remain BKN-OVC through the day Thu. These clouds will likely push back in a little earlier tomorrow for the inland areas, and extend a little further eastward, as bases will be slightly more elevated from where they were today, beginning around 00Z Fri, with bases of around 1200-1800 feet MSL. These bases will continue to lower again throughout the overnight hours tomorrow night, although maybe not quite as low as where they are expected to be tonight. Mountains/Deserts...SCT high clouds and unrestricted vis expected through tomorrow night. && .MARINE... No hazardous marine conditions are expected today through Monday. && .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...PG AVIATION/MARINE...Stewey