Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
192 FXUS66 KSGX 081729 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 929 AM PST Mon Dec 8 2025 .SYNOPSIS... Warm and dry conditions with periods of Santa Ana winds expected this week. The peak of the heat is expected Tuesday and Wednesday. Mostly clear skies will prevail through Friday, with low clouds and fog returning to coastal areas as early as Saturday morning. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... At 9 AM there were a few patches of low clouds and fog just off the coast, with clear skies elsewhere. Low clouds and fog are not expected to impact land areas through much of this week due to persistent offshore flow. The pressure gradient will switch onshore this weekend with chances of low clouds and fog developing at the coast and western valleys as early as Saturday. A surface high pressure over the Great Basin will remain in place through Friday. This will bring weak to locally moderate Santa Ana winds to the area. With no upper level support, the strongest winds will remain confined to coastal mountain slopes, foothills, and below passes. The strongest winds are expected today into Tuesday morning with gusts 25 to 45 mph. A secondary peak in winds is expected on Friday, with similar wind speeds expected. The airmass getting pushed into Southern California from the Great Basin will be dry, with minimum afternoon relative humidity for inland areas falling to 10 to 20% each afternoon through Friday, bringing periods of elevated fire weather conditions. An upper level ridge over the East Pacific will remain over the US West Coast through Tuesday, bringing an uptick in high temperatures. High temperatures on Tuesday will be 15 to 20 degrees above average. Widespread highs in the low to mid 80s are forecast across the inland coastal areas into the valleys as well as the low deserts. Weaker Santa Ana winds and a weakening in the upper level ridge will allow for minor cooling for the coast on Wednesday with further cooling into the valleys on Thursday but highs will remain 10 to 20 degrees above average. Nights and mornings will remain cool, especially in the wind-sheltered areas, minimizing any heat impacts. Further cooling is expected into next weekend as weak onshore flow returns, but temperatures will continue to run above average. && .AVIATION... 081600Z...Clear and VFR conditions will prevail through Tuesday morning. Pockets of northeast winds gusting 25-35 kts mainly in foothills and adjacent valleys after 20Z. && .MARINE... Tonight, 30-40% chance for patchy fog development over the marine waters. Otherwise, no hazardous marine conditions are anticipated through Saturday. && .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...CO AVIATION/MARINE...Westerink