Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
732 FXUS66 KSGX 312017 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 117 PM PDT Thu Jul 31 2025 .SYNOPSIS... Quiet weather will continue with temperatures near average and night and morning low clouds each day along the coast and western valleys. High pressure over the Desert Southwest may strengthen by the middle of next week, bringing a warmer trend with temperatures near 5 to 10 degrees above average away from the coast. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... A broad trough is draped across the W Pac and West Coast states, bringing weak onshore flow and temperatures near average. High pressure to the south will try to gain strength over the weekend, but the troughing pattern will continue over California, keeping temperatures moderated with minimal day to day changes. The lower deserts will feel the "greatest" warming with better chances to climb over 110 degrees. Marine layer clouds will stay confined to the coast and western valleys each night and morning, with areas of fog across higher terrain and in valleys, especially this weekend. Ensemble models are in fair agreement of the high pressure currently over Mexico will move over the Desert Southwest by next week and strengthen. The high may expand far enough west to bring a warming trend by Wednesday into Thursday of next week. If this occurs, inland areas could see highs 5 to 10 degrees above average. Right now, chances are around 50% to see highs reach 115 degrees in the lower deserts with a 65-80% chance of seeing highs reach 100 degrees across the Inland Empire and high desert. Uncertainty still exists in exactly how much we warm up, but dry weather certainty remains high for the upcoming week`s forecast. && .AVIATION... 312030Z....Coasts/Western Valleys...Low clouds and fog with bases 700-1100 feet MSL, tops to 1500 feet, and vis 0-5SM over higher terrain will begin to develop after 04Z and move locally inland after 06Z. Scatter out Friday 16-17Z. .Inland Valleys/Mountains/Deserts...Mostly clear with VFR conditions through Friday. && .MARINE... No hazardous marine conditions are expected through Monday. && .BEACHES... For beaches and harbors...Small water level fluctuations will continue periodically from the diminishing tsunami. && .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...MM