Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
186 FXUS66 KSGX 131623 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 923 AM PDT Mon May 13 2024 .SYNOPSIS... For much of the week, night and morning coastal low clouds will spread inland across much of the valleys with limited or slow afternoon clearing for the beaches. A weak low pressure system moving inland across southern California for Tuesday night and Wednesday could bring a few light showers to the mountains for Wednesday afternoon with the chance of measurable precipitation less than 15 percent. There will be warming for most areas for Thursday and Friday with Friday high temperatures as much as 5 to 10 degrees above average for the deserts. This will be followed by a cooling trend for Saturday through Monday with Monday high temperatures cooling to around average for the deserts with the coast and valleys a few to around 5 degrees below average. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Update... The 12z Miramar sounding showed a 9C degree inversion based near 2000 feet, with a saturated layer as low as 700 feet. Low clouds blanket the coast and valleys as of 9 AM, but clouds are slowly starting to clear from the eastern valleys. Most inland areas will clear by late morning or early afternoon, but the coast will continue to see passing clouds through most of the day. A 576 DM low is just off the coast of central California and a weakening ridge axis is over the Great Basin today. Onshore flow prevails today spreading slight cooling inland across the coast and western valleys, and warming along the desert slopes and deserts. Highs look to range from the 60s to lower-70s across the coast and western valleys as well as the mountains, the low-80s in the Inland Empire, the mid-80s in the High Desert and near 100 degrees in the lower deserts. Previous Discussion (Issued 341 AM PDT Mon May 13 2024)... .SHORT TERM (Today through Wednesday)... The marine layer will fluctuate around 2500 to 3000 feet deep for much of the week. Night and morning coastal low clouds will spread inland across much of the valleys with limited or slow afternoon clearing for the beaches. A weak upper level low pressure system well off the California coast will move inland through southern California on Tuesday night and Wednesday. This could bring a few light showers to the mountains for Wednesday afternoon with the chance of measurable precipitation less than 15 percent. NBM has the greatest chance for measurable rainfall in the San Bernardino Mountains on Wednesday afternoon of around 13 percent. The experimental FV-3 ensemble also shows some very light precipitation in portions of the mountains for Wednesday afternoon. High temperatures for the coast and valleys will cool slowly through Wednesday with not much change for the deserts. && .LONG TERM (Thursday through Sunday)... High temperatures will warm for most areas for Thursday and Friday. High temperatures for the deserts will warm to 5 to 10 degrees above average for Friday, to around 105 for Palm Springs. Then slowly cooler for Saturday through Monday with Monday high temperatures around average for the deserts and a few to around 5 degrees below average for the coast and valleys. && .AVIATION... 131600Z...Coast/Valleys...Low clouds with bases 1000-1300 feet MSL will clear to the coast through about 18Z. Only partial or intermittent clearing expected at the immediate coast this afternoon. Low clouds with bases 1000-1500 ft MSL, locally to 800 ft MSL expected to push inland after 01Z. Local vis reductions of 2-5 SM in the valleys and 0-5 SM where clouds obscure higher terrain. Similar clearing pattern and timing expected Tuesday. Mountains/Deserts...Mostly clear with unrestricted VIS through tonight. SCT/BKN clouds over the mountains with bases around 9000 feet MSL 18-02Z. West winds gusting locally 25-35 kts through mountain passes into adjacent desert slopes after 23Z. && .MARINE... No hazardous marine conditions are expected through Friday. && .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...EA/17 AVIATION/MARINE...CO