Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
087 FXUS66 KSGX 222126 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 126 PM PST Sat Feb 22 2025 .SYNOPSIS... A warming trend sets in for much of the week, with temperatures reaching 10-20 degrees above normal by Wednesday when elevated Santa Ana winds return. A pattern shift late in the week brings a return of cooler weather and a chance of light precipitation into the weekend. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Warm weather and light winds prevail today and tomorrow as weak upper level ridging moves in. The dense fog that was observed this morning is expected once again Sunday morning with similar coverage and extent, generally along the coast/beaches and up to 5-10 miles inland. Temperatures will slowly warm through Monday/Tuesday with zonal flow aloft, providing afternoon highs in the 70s along the coasts, 80s for the valleys and inland areas, 60s and 70s for the mountains, and 80s to 90s for the deserts. A closed low over the PacNW will transition to an open trough and sweep down to the Four Corners on Wednesday, with gusty offshore winds developing across much of the region. Despite the weak to moderate easterly flow, elevated fire weather conditions may exist on Wednesday as relative humidity plummets to single digits everywhere east of the valleys. This dry, warm flow will also cause temperatures to soar as highs reach near 20 degrees above normal, reaching the 90s for some desert areas. While temperatures peak Wednesday, highs remain exceptionally warm into Thursday as the trough slowly propagates southward through Arizona. Given these unseasonably hot temperatures, those outside may be caught off guard by the heat. Make sure to practice proper heat safety, remaining hydrated and taking frequent breaks in the shade, and avoid outdoor work during the hottest hours of the day. The pattern changes substantially on Friday as the prevailing hot and dry weather comes to an end. While there remains substantial disagreement with the models later this week, some runs continue to indicate a chance for some precipitation as a upper level low moves into Southern California on Friday, followed closely by a secondary trough set to come across late weekend. The signal remains fairly weak for precipitation with this first low, chances slightly better with the second, but there is still good agreement on the substantially cooler weather expected to accompany this pattern shift. Highs may fall drastically Friday compared to Thursday, closer to near normal, with the cooler weather prevailing through the weekend. && .AVIATION... 212200Z...Coast/Inland Valleys...Clouds will redevelop and push back ashore after 06z this evening into Sunday morning, with very similar coverage, CIGs, and VIS as this morning. Some of these low CIGs/FG/BR could extended into portions of the inland areas again, especially within the Mission Valley, otherwise the majority of the inland valleys will remain VFR for the most part. There could also be localized areas of patchy fog out over the coastal waters, otherwise bases will hover around 100-200 feet MSL. This will begin to erode from east to west between 16-17Z tomorrow morning and scatter out shortly thereafter along the coastal areas, with intermittent BKN coverage possible around 500-1000 feet MSL along the extreme coastal areas during the afternoon hours tomorrow. Expect low clouds and patchy fog, with bases of 100 to 500 feet MSL, to return again by later in the evening tomorrow after 06Z Monday, and continue to fill into some of the inland valleys through Monday morning. Valleys/Mountains/Deserts...Mostly clear skies with unrestricted VIS will prevail through Sunday. && .MARINE... No hazardous marine conditions are expected through Wednesday. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...Zuber AVIATION/MARINE...Stewey