Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
628 FXUS66 KSGX 112041 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 141 PM PDT Sat May 11 2024 .SYNOPSIS... Low clouds and fog expected each night and morning for the coast and valleys through the next week. A few degrees of warming is expected Sunday, with cooling Monday and Tuesday. A few light rain showers may develop over the mountains Tuesday and Wednesday afternoons, with minimal accumulations expected. There is some uncertainty in the forecast for the latter half of next week, but temperatures for inland locations look to stay near or a few degrees above average for this time of year. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Low clouds are sticking along the beaches as of 1 PM this afternoon, with some low topped cumulus development along the mountains. Night and morning low clouds and fog are expected to remain present each day through next week. Some fluctuation on how far inland low clouds push each night is expected, with a lesser inland extent for the first half of the week and a deeper marine layer possible towards the middle to end of next week. Weak ridging is expected over Southern California Sunday. This will allow for a brief warming trend, most noticeable for inland areas. Highs in the lower deserts are expected to hit 100 degrees on Sunday. Elsewhere on Sunday, highs will generally be several degrees above normal inland, but close to normal for the coastal areas and western valleys due to the persistent marine layer. The ridge will shift east on Monday as a weak closed low moves towards the region, slowly moving through on Tuesday and finally passing east late Wednesday or early Thursday. This will result in a couple degrees of cooling each day through the middle of the week. In addition to slightly cooler conditions and the potential for a deeper marine layer Tuesday and Wednesday, a slight chance (15-18%) of showers has been added to the forecast for portions of the mountains. Current guidance has the best chances of showers Wednesday afternoon for the San Bernardino, Riverside, and San Diego mountains. Isolated showers are possible on Tuesday afternoon as well, most likely in the San Bernardino Mountains. The incoming low is expected to be weak, with minimal moisture associated with it. Even with the moisture limitations, ensemble members of both the ECMWF and GFS are showing the potential for showers with light rainfall accumulations over the portions of the mountains. Overall, there is moderate confidence in the rainfall forecast, both in amounts and timing. Guidance for the latter half of the week continues to be conflicting with continued spread in the ensemble solutions regarding the position of the East Pacific ridge and the potential for troughing across the Western US. This creates a wide range of possibilities for temperatures. Current forecast for high temperatures follows the NBM which keeps conditions near to slightly below normal for areas west of the mountains and above normal for the deserts. && .AVIATION... 112020Z...Coast/Valleys...Mostly clear skies will continue this afternoon for areas away from the coast as low clouds near 1200-1800 ft MSL stick near the coast. Low clouds will come back inland after 00Z Sunday filling most valleys of San Diego and Orange Counties after 03Z Sun. Low to moderate confidence on cigs reaching the Inland Empire tonight, best chance VCTY KONT. Mountains/Deserts...Mostly clear with unrestricted VIS through this afternoon and evening. SCT/BKN clouds over the mountains with bases around 9000 ft MSL through this afternoon. Breezy west winds for SD/RIV County mountain passes and deserts near 20-30 kts until 08Z Sun. && .MARINE... No hazardous marine conditions are expected through Wednesday. && .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...CO AVIATION/MARINE...APR