004 FXUS66 KSGX 151207 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 507 AM PDT Tue Mar 15 2022 .SYNOPSIS... Through Friday, the lower level flow will alternated between weak onshore and weak offshore, cooler with the onshore with more night and morning coastal low clouds and fog, and warmer with the weak offshore with fewer coastal low clouds. For the weekend, a stronger trough of low pressure will move inland through southern California spreading cooling inland. There will also be stronger and gusty southwest to west winds for the mountains and deserts and a slight chance for light precipitation. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Through Friday, the lower level flow will fluctuate between weakly onshore and weakly offshore as a series of weak low pressure and weak high pressure systems move inland across the area in progressive westerly flow. A weak trough of low pressure will move inland through California late today and tonight and again late Thursday with high pressure aloft on Wednesday night and around Friday. The periods of onshore flow will spread cooling inland into the coast and valleys with warming in between with weak offshore and high pressure aloft. For early this morning, there is a weak coastal eddy with satellite imagery showing stratus spread northward along the coast of Baja and southern California as far north as southern Los Angeles County. In San Diego County, the low clouds and fog have been as far inland as the mesas, but the eastern edge has migrated back toward the coast. Higher resolution models continue to move the eastern edge slowly westward early this morning. There is also a more extensive area of low clouds spreading southward just beyond the offshore islands. For tonight into Wednesday morning with stronger onshore flow and a weak coastal eddy, coastal low clouds and fog should be more extensive and spread inland into the western San Diego County valleys and northward across much of the Orange County coastal plain. A stronger trough of low pressure will move inland through southern California over the weekend. There remain timing and amplitude differences among the global ensemble systems with this low pressure system. It will spread cooling inland for Saturday and Sunday and bring a period of stronger and gusty southwest to west winds in the mountains and deserts. There is a also chance of mostly light precipitation with the most likely time for any precipitation Saturday night into Sunday morning, but with precipitation possible as early as Saturday or as late as Sunday night. && .AVIATION... 150930Z....Areas of low clouds along the coast will be based at 400- 700 feet MSL with vis 2-5SM through 15Z. Otherwise, mostly clear skies will prevail today, but with increasing high clouds after 23Z. && .MARINE... Northwest winds with gusts over 20 knots are expected Wednesday, Thursday evening and late Saturday in the outer waters. These winds along with choppy sea conditions could be hazardous for small craft during these periods. Otherwise, no hazardous marine conditions are expected through Saturday. && .BEACHES... Elevated surf and strong rip currents will occur tonight through Thursday when some sets up to 6 feet are possible. && .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...17 AVIATION/MARINE/BEACHES...MM