Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
904 FXUS66 KSGX 061642 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 942 AM PDT Mon May 6 2024 .SYNOPSIS... Dry and warmer, with gusty winds from the west over the mountains and into the deserts today and Tuesday. A brief bout of offshore winds will occur Wednesday, leading to additional warmth west of the mountains. Another gradual warming trend looks likely heading into this weekend, with no precipitation in the foreseeable future at this time. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... The cold low pressure system responsible for this past weekends cool, breezy, and wet weather will continue pushing eastward across the Rockies today as high pressure slowly nudges inland from over the Pacific. Accordingly, the onshore flow will weaken, setting the stage for a notably warmer day than yesterday. Highs today look to climb 5-10 degrees warmer than yesterdays at the coast, about 10-15 degrees warmer across the inland valleys as well as both the High and Lower Deserts, and upwards of 15-20 degrees warmer across the mountains. The warming trend generally continues, albeit just by a few additional degrees, through Tuesday afternoon for most locations. The marine layer will gradually become more and more shallow during this time with low clouds and fog sticking closer to the coast and western coastal valleys. There will still be gusty onshore winds over the mountains and into the deserts in the afternoons and evenings both today and Tuesday. With a weaker pressure gradient, the winds will accordingly be weaker than yesterday. A weak low pressure system passing through the Great Basin Tuesday and Tuesday night will strengthen the pressure gradient again. With all this in mind, wind gusts of 40-50 mph can be anticipated below mountain passes and through wind-prone canyons during the traditional late afternoon and evening hours. The development of a very strong upper level low pressure system over the Northern High Plains, and its influence expanding westward as it strengthens, will cause a quick bout of offshore flow on Wednesday. It will drop temperatures in the deserts by a few degrees but will continue the warming trend for areas west of the mountains. The offshore flow itself does not appear to be overly impactful, with perhaps a few gusts of 30-35 mph in the Santa-Ana-favored areas below passes and through canyons. The forecast then gets a bit more murky from Thursday onward. The aforementioned strong upper low will cause a larger-scale troughing pattern to set in over SoCal. This will support a deeper marine layer with clouds and fog extending farther inland. Temperature trends during this time look to be highly dependent on marine layer coverage and duration of low clouds each morning/afternoon. Eventually the low and attendant trough look to weaken which would support another gradual warming trend, though exactly when that will take place appears uncertain at this time. && .AVIATION... 061630Z...Coasts/Valleys/Foothills...Mostly clear conditions with unrestricted visibilities through this evening. Areas of low clouds to redevelop in coastal areas after 06Z into Tuesday morning, with bases around 1200-1800 feet MSL. Mountains/Deserts...Mostly clear conditions with unrestricted visibilities will prevail over the next 24 hours. && .MARINE... No hazardous marine conditions are expected today 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...Adams AVIATION/MARINE...Suk