992 FXUS66 KSGX 071058 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 258 AM PST Sun Nov 7 2021 .SYNOPSIS... A developing trough along the West Coast will keep the weather cool west of the mountains, with night and morning low clouds and patchy fog through Tuesday. Some drizzle is possible again early Wednesday morning, otherwise, dry weather will prevail. Winds will turn offshore during the latter half of the week, with Santa Ana conditions beginning on Thursday. Friday should be the warmest day overall, with temperatures some ten to fifteen degrees above average over the coast and valleys. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Low clouds have spread well inland early this morning, covering much of the I.E. and the valleys of San Diego County. Near the leading edge of this cloud cover, fog was reported and was locally dense. Some patchy drizzle has been reported as well. Higher clouds were visible in satellite imagery drifting NE over SE portions of the CWA. Weak to moderate onshore sfc pressure gradients were supporting better westerly winds through the passes at 15-25 MPH, with a few higher gusts. Widespread low dewpoint depressions and several reports of fog with visibility 1/4 mile or less, have prompted a Dense Fog Advisory for portions of the valleys above 800 FT. Expect gradual clearing of the low clouds and fog later this morning, with some of the higher clouds remaining through the afternoon. With the deeper marine layer, it will be a bit cooler today, and remain below average through Tuesday west of the mountains. Temperatures should be about average over the mtns/deserts. A broad trough along the West Coast will keep SoCal cool, with night and morning low clouds and patchy fog through Tuesday. On Wednesday, high pressure will begin to build off the coast, which will peak on Friday. This will initiate a warming and drying trend across the region as winds turn offshore and Santa Ana conditions develop. East to northeast winds will become gusty below the passes and along the coastal foothills, pushing the marine layer back offshore. Look for much lower humidity, and very warm afternoons, particularly along the coast and in the western valleys where temperatures are expected to be some 10-15F above average. The ridge offshore peaks in amplitude about Friday before deflating and shifting inland over the weekend. This should result in gradual cooling beginning as early as late Saturday, and continuing through early next week. && .SKYWARN... Skywarn activation is not requested. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Dense Fog Advisory until 9 AM PST this morning for San Bernardino and Riverside County Valleys-The Inland Empire- San Diego County Valleys. PZ...NONE. && $$ PUBLIC...10 AVIATION/MARINE...Connolly