Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
136 FXUS66 KSGX 161036 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 336 AM PDT Thu May 16 2024 .SYNOPSIS... A persistent marine layer typical of May will continue into next week with night and morning coastal low clouds extending well inland across most of the valleys with limited afternoon clearing for coastal areas. Through Saturday, not much change is expected with high temperatures for the coast and valleys with slight cooling for the deserts. Cooling for most areas for Sunday and Monday, then a little warmer for 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)... The marine layer is around 4000 feet deep early this morning with low clouds extending inland across all of the coast and valleys and onto the lower coastal slopes of the mountains. There has been some patchy drizzle with some light measurable amounts for inland Orange County and in the western valleys in San Diego County. The deep marine layer will continue into the weekend. Night and morning low clouds will extend will inland across most of the valleys and sometimes onto the lower coastal mountain slopes. Afternoon coastal clearing will remain limited. Through Saturday, high temperatures for the deserts will cool a degree or so per day with not much change for the coast and valleys. && .LONG TERM (Sunday through Wednesday)... A weak upper level low pressure system well off the northern Baja coast on Saturday will move eastward and move inland through southern California and northern Baja some time around Monday. High temperatures on Sunday will be another degree or two cooler than Saturday with Monday another 5 or so degrees cooler for inland areas. With that cooling, high temperatures on Monday will be around 5 degrees below average for lower elevations to generally 8 to 12 degrees below average for the mountains and inland valleys. High temperatures for the coast and valleys will be mostly in the 60s with some lower 70s in the Inland Empire. Highs in the lower deserts on Monday will be mostly in the mid 80s to mid 90s. High temperatures for Tuesday and Wednesday will be slightly warmer with Wednesday generally a few to around 5 degrees warmer than Monday. && .AVIATION... 160930Z...Coast/Valleys...Low clouds filling the coastal basin with bases will expand again this evening and cover all valley locations by 08Z Thu, with bases 1800-2400 feet MSL and tops 3500-4000 feet. Vis reduced in foothills. Slow clearing toward the coast 16-20Z, but with little or no clearing near the coast. Low clouds spreading back inland 00-03Z tonight and filling the coastal basin overnight into Friday with bases 1400-2000 feet MSL. Mountains/Deserts...Mostly clear today and tonight. West winds will gust locally 25-35 kt through mountain passes into adjacent deserts through 16Z, then again after 23Z. && .MARINE... No hazardous marine conditions are expected through Monday. && .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...MM