Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
265 FXUS66 KSGX 231018 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 318 AM PDT Thu May 23 2024 .SYNOPSIS... Cooling through Saturday with gusty southwest to west winds for the mountains and deserts with the strongest gusts on Friday afternoon into Friday night. Night and morning coastal low clouds will extend inland across all of the valleys and onto the lower coastal slopes of the mountains with slower daytime clearing for coastal areas. High pressure to the south will bring warming for Sunday through Wednesday. The marine layer will become shallower with night and morning coastal low clouds only extending inland into portions of the valleys by the middle of next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (Today through Saturday)... A trough of low pressure moving inland through southern California tonight and Friday will bring stronger onshore flow. The marine layer will deepen, cooling will spread inland, and there will be periods of gusty southwest to west winds for the mountains and deserts with the strongest winds for Friday afternoon into Friday night. There is a coastal eddy early this morning. The marine layer has deepened to around 3500 feet with coastal low clouds extending inland across all of the valleys and onto the lower coastal slopes of the mountains. Additional deepening to 4500 to 5000 feet is expected for Friday night into Saturday morning with patchy drizzle possible. There will be gusty southwest to west winds for the mountains and deserts with the stronger winds on Friday and Saturday and the strongest winds for Friday afternoon into Friday night with the stronger gusts to 40 to 50 mph and the strongest gusts in the northern Coachella Valley below the San Gorgonio Pass to around 60 mph. High temperatures today will cool a few degrees from those on Wednesday. There will be greater cooling on Friday. The deserts will continue to cool slightly on Saturday while the coast and valleys warm slightly. With the cooling, high temperatures for the mountains and inland valleys will be as much as 10 to 15 degrees below average on Friday. && .LONG TERM (Sunday through Wednesday)... High pressure to the south will bring warming through the middle of next week. The greatest warming is expected for Sunday and Monday with slight additional warming for Tuesday and Wednesday. With the warming, high temperatures on Wednesday will be around average for the coast and valleys and around 5 degrees above average for the deserts, mostly in the 80s for the Inland Empire and the upper 90s to 104 for the lower deserts. The marine layer will gradually decrease in depth with night and morning coastal low clouds only extending inland into portions of the valleys by the middle of next week. && .AVIATION... 230915Z...Coast/Valleys/Foothills...Low clouds with bases 1900-2500 FT MSL extend through the foothills this morning. Locally reduced vis where low clouds and terrain intersect. Scatter out 18-21z Thu across inland areas, with CIGS remaining at the coast. Low clouds progressing back inland after 23z Thu with slightly higher bases. Mountains/Deserts...Clear skies with unrestricted VIS through tonight. W-NW wind gusts of 20-35 kt over/east of mtns after 00z Fri, with weak-mod up/downdrafts and LLWS over/east of the mtns. && .MARINE... Northwest winds gusting near 20 knots in the outer waters 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...Wind Advisory from noon Friday to 2 AM PDT Saturday for San Gorgonio Pass Near Banning. PZ...None. && $$ PUBLIC...17 AVIATION/MARINE...EA