Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
029 FXUS66 KSGX 221007 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 307 AM PDT Wed May 22 2024 .SYNOPSIS... Warmer today. Stronger onshore flow with a cooling trend for Thursday through Saturday. The marine layer will deepen with night and morning low clouds extending well inland across all of the valleys and onto the lower coastal slopes of the mountains with more limited daytime clearing for coastal areas. There will be periods of stronger and gusty southwest to west winds for the mountains and deserts with the stronger gusts to 40 to 50 mph on Friday and Saturday. High pressure to the south will bring a warming trend for Sunday into the middle of next week with Wednesday high temperatures around average for the coast and valleys and around 5 degrees above average for the deserts. Winds will weaken for the mountains and deserts. By the middle of next week, night and morning coastal low clouds will extend inland only into portions of the valleys as the marine layer decreases in depth. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (Today through Friday)... The marine layer is around 2500 to 3000 feet deep. Extensive low clouds over the coastal waters extend inland across the coastal areas and much of the San Diego County valleys. Through sunrise, the low clouds should begin to spread into portions of the Inland Empire. For Thursday into the weekend, night and morning coastal low clouds will extend well inland across all of the valleys and onto the lower coastal of the mountains as the marine layer deepens. Daytime clearing will be more limited for coastal areas. High temperatures today will be a few to around 5 degrees warmer than Tuesday, mostly in the 70s for the Inland Empire and 90s for the lower deserts. There will then be a cooling trend for Thursday into the weekend with high temperatures on Friday as much as 10 to 15 degrees below average for the mountains and Inland Empire. Onshore flow will strengthen for Thursday and Friday with stronger and gusty southwest to west winds for the mountains and deserts with the stronger gusts on Friday to 40 to 50 mph. && .LONG TERM (Friday night through Tuesday)... The marine layer will continue to deepen into the weekend, to around 4000 feet. There could be some patchy drizzle for coastal areas and the San Diego County valleys for late Friday night into Saturday morning. The marine layer will decrease in depth for early next week with the depth of the marine layer decreasing to around 2000 feet for the middle of next week. Night and morning coastal low clouds will extend inland across all of the valleys and onto the lower coastal slopes of the mountains for the weekend, then only extend inland into portions of the valleys by the middle of next week. High temperatures for Saturday will be similar to Friday with high temperatures near the coast around 5 degrees below average and as much as 15 to 20 degrees below average in the mountains with high temperatures mostly in the 60s for the coast and valleys and in the 80s for the lower deserts. High pressure to the south will bring a warming trend for Sunday into the middle of next. High temperatures on Memorial Day will warm to a few degrees above average for the deserts and will still be a few degrees below average for the coast and valleys. The warming will continue into Wednesday with Wednesday high temperatures for the deserts around 5 degrees above average and for the coast and valleys around average, mostly into the 80s for the Inland Empire and the upper 90s to 105 for the lower deserts. Stronger onshore flow will continue into Saturday with gusty southwest to west winds for the mountains and deserts with the stronger gusts to 40 to 50 mph. Winds for the mountains and deserts will then weaken into the middle of next week. && .AVIATION... 220915Z...Coast/Valleys/Foothills...Low clouds with bases 1600-2000 FT MSL extend up to 30 SM inland. Reduced vis of 2-4 SM, locally below 1 SM where low clouds and terrain intersect. Low clouds vcty KONT/KSBD 11z-16z Wed. Scatter out across inland areas 16z-18z Wed, and limited clearing at the coast 19z-23z Wed. Mountains/Deserts...Clear skies with unrestricted VIS through Wed night. W-NW wind gusts of 20-35 kt over/east of mtns after 00z Thu. && .MARINE... Northwest wind gusts up to 20 knots will be possible each afternoon and evening Friday through Sunday. && .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...Martin AVIATION/MARINE...EA