Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
167 FXUS66 KSGX 172037 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 137 PM PDT Fri May 17 2024 .SYNOPSIS... A seasonally persistent marine layer will continue for the coming week with night and morning coastal low clouds extending well inland across the valleys with limited or slow afternoon clearing for coastal areas. There will be periods of stronger, gusty westerly winds for portions of the mountains and deserts during late afternoons and nights through Monday. High temperatures will continue slightly below normal in general, although cooler early next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... The low cloud cover has been stubborn today, with clearing getting traction only in the far inland valleys so far. The marine inversion this morning was strong, and that has discouraged a full mix-out of clouds. If you`re near the coast, don`t expect to see much if any sunshine today. Our daily pattern of winds in the mountains and deserts will continue, with strongest gusts 35-50 mph through mountain passes into adjacent deserts. May Gray will continue in full swing as a weak trough pattern over the West continues for the coming week. Within the overall longwave trough pattern, there will be shortwaves to provide barely noticeable variations on the theme. These will tweak the marine layer depth, temperatures, and wind speeds in the mountains and deserts from day to day. A deeper trough of low pressure will move through the West and pick up a weak low currently off the coast to our west. Models are pretty certain that Monday will feel the biggest effects from this well-defined feature: a deeper marine layer, stronger winds in mountains and deserts, and cooler regionwide. Tuesday and beyond, the timing and strength of shortwaves vary more with a wider spread of ensemble solutions. But none of the solutions indicates any big variations in our overall marine layer dominated pattern. We`ll continue running a little below normal for max temps west of the mountains, and a little above normal in mountains and deserts this weekend. Monday should be cooler than normal for all areas, followed by a trend back toward normal, but not quite reaching it, Tuesday through Friday. && .AVIATION... 172010Z...Coast/Valleys...Low clouds with bases 1800-2500 FT MSL extend through much of the coastal basin this afternoon, but are starting to diminish across the eastern valleys. Limited scatter out across western valleys/coast this afternoon. Low clouds spreading back inland after 00z Sat with bases 1000-2000 FT MSL. Mountains/Deserts...Mostly clear today becoming SCT AOA 20,000 FT MSL late tonight. Gusty W-SW winds with gusts 25-40 kt, strongest 23z Fri-10z Sat. MOD up/downdrafts and LLWS possible over/E of the mtns. && .MARINE... No hazardous marine conditions through Tuesday. && .BEACHES... A series of southwest swells of 2-3 ft at 17-18 seconds from 210 degrees will build through Sunday and continue through Tuesday, producing above normal surf of 3-5 ft with locally higher sets on exposed SW facing beaches, as well as a high risk of rip currents at all beaches. Swell and surf will begin to slowly lower on 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...MM AVIATION/MARINE/BEACHES...EA