Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
764 FXUS66 KSGX 190417 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 915 PM PDT Sat May 18 2024 .SYNOPSIS... A persistent trough over the West Coast through next week will keep temperatures a little below average and generate gusty mountain and desert winds each afternoon. Night and morning marine layer clouds will retreat back to the coast each afternoon. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Low clouds cleared back to the coastal waters early today due to a shallower marine layer and a weaker inversion. This evening they were starting to move back inland. At 9 PM the low clouds surged back into coastal San Diego County from Camp Pendleton to La Jolla, but San Diego was still mostly clear. The clouds will spread into the valleys overnight. The 00Z NKX sounding showed a marine layer depth near 2000 feet. Longwave troughing over the West Coast will continue through next week. On Sunday and Monday an embedded shortwave in the longwave trough will move across the Great Basin and bring a burst of gusty northwest winds to SoCal Mountains and deserts each afternoon and evening. It will also bring a cooler airmass into the Southwest, and Monday will be the coolest day of the week with highs in the low 60s near the coast, near 70 in the inland valleys, the 50s in the mountains, the 70s in the high deserts, and near 90 in the lower deserts. Areas of drizzle in the deep marine layer are likely west of the mountains Monday morning. After the trough axis passes, heights rise slightly for warmer days Tuesday and Wednesday. Then another shortwave digging down the West Coast will bring a few degrees of cooling Thursday and Friday. && .AVIATION... 190400Z...Coast/Valleys... BKN/OVC low clouds will continue to expand this evening, reaching most areas by 08Z Sun with bases 1300- 1900 ft MSL and tops to 2400 ft MSL and higher terrain obscured. Below the cloud deck vis will mostly be unrestricted. Local -DZ could occur 10Z-16Z Sun. Clearing Sun will occur 16Z-19Z in the valleys and 18Z-21Z near the coast with some locations within 5 miles of the coast having BKN CIGs continuing after 21Z Sun. Low clouds will spread rapidly inland Sun evening. Mountains/Deserts... Clear skies with unrestricted VIS will prevail through Sun evening. Areas of W-SW winds with gusts 30-45 kt from the mountain crests east through the desert slopes and into the deserts will continue at times through Sun evening, accompanied by MOD UDDFS and LLWS over/E of the mtns. && .MARINE... No hazardous marine conditions are expected through Thursday. && .BEACHES... A series of southwest swells of 2-3 ft at 16-18 seconds from 200-220 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 slowly lower Wednesday and Thursday. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...Moede AVIATION/MARINE/BEACHES...Maxwell