Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
979 FXUS66 KSGX 311640 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 940 AM PDT Fri May 31 2024 .SYNOPSIS... A weak trough over the Southwest and a Catalina Eddy over the coastal waters will keep a deep marine layer in place through early next week. High temperatures will be a few degrees below average west of the mountains, and a few degrees above average in the mountains and deserts. High pressure building over the West next week will bring warmer days Wednesday and Thursday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... The 12Z NKX sounding showed the marine layer depth at 2500 feet this morning, deep enough for low clouds to spread into the valleys near Ramona, Temecula and San Bernardino. Clouds will slowly burn back to the coast this afternoon. This low cloud pattern will repeat Saturday, Sunday and Monday as a weak trough over the West and a Catalina Eddy over the coastal waters combine forces to the keep a deep marine layer in place. There may be patchy morning drizzle each day, the most widespread on Monday morning when the marine layer will the deepest. Sunday and Monday will be the coolest days as that will be when the trough axis passes, the Catalina Eddy will be strongest and the marine layer will be the deepest. Highs will be in the mid to upper 60s near the coast, the 70s and low 80s in the valleys, the 70s in the mountains, near 90 in the high deserts and from 100-105 in the lower deserts. The trough will also produce gusty west winds each afternoon and evening in the mountains and deserts this weekend. On Tuesday the trough moves east, replaced by weak ridging and warmer days Wednesday and Thursday when highs will be in the upper 60s and low 70s near the coast, the 80s in the valleys, near 90 in the eastern sections of the Inland Empire, the 80s in the mountains, from 95-100 in the high deserts and from 105-110 in the lower deserts. && .AVIATION... 311630Z...Coast/Valleys...Low clouds with bases 1000-1500 feet MSL with tops to 2600 feet will clear the valleys through 18Z and coastal areas 18Z-21Z with areas of lingering BKN low clouds within 3 miles of the coast through this afternoon. Local vis 2-4 miles will continue in the valleys through 18Z. Low clouds will spread inland again, to 20 miles inland 01Z-06Z Sat and through most of the valleys by 12Z Sat. Bases will be 1000-1500 ft MSL with tops to 2500 feet, and higher terrain will be obscured. Areas of vis 2-4 miles with local vis below 1 mile will occur 06Z-17Z Sat. Low clouds will clear slowly in the valleys Sat morning, mostly 16Z-19Z with only partial clearing at the coast Sat. Mountains/Deserts...Clear skies with unrestricted VIS will continue through Sat morning. && .MARINE... No hazardous marine conditions are expected through Tuesday. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...Moede AVIATION/MARINE...Maxwell