939 FXUS66 KSGX 030704 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 1204 AM PDT Wed Jun 3 2026 .SYNOPSIS... High pressure aloft will bring warming through Thursday with high temperatures for inland areas 5 to 10 degrees above average on Thursday. Coastal low clouds will only extend into the western valleys for early Thursday and early Friday as the marine layer becomes a little shallower. A low pressure system moving into the western states will bring cooling and deepening of the marine layer for the weekend with coastal low clouds extending onto the coastal slopes of the mountains early Sunday. This will be followed by a gradual warming trend for early next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (Today through Friday)... Subtropical high pressure aloft over the eastern Pacific will expand across southern California through Thursday, then begin to weaken on Friday. High temperatures for today will warm as much as 4 to 8 degrees for the inland valleys and coastal slopes of the mountains with most areas warming a few more degrees on Thursday. High temperatures will begin to cool for the valleys on Friday by a few degrees. High temperatures on Thursday will be as much as 5 to 10 degrees above average for the mountains, deserts, and inland valleys with coastal areas a few degrees above average. High temperatures on Thursday will range from the lower 70s near the coast to the mid 80s to mid 90s for the Inland Empire with 104 to 108 for the lower deserts. Coastal low clouds are expected to spread into portions of the inland valleys early today. The marine layer is expected to decrease in depth later today to around 2000 feet with coastal low clouds only spreading inland into the western valleys for early Thursday and early Friday. && .LONG TERM (Sunday through Tuesday)... A low pressure system will move inland into the western states during the weekend. The greater cooling of high temperatures for southern California is expected on Saturday with the cooling continuing through Sunday. High temperatures on Sunday will be a few degrees below average to around 5 degrees below average for the inland valleys onto the coastal slopes of the mountains. High temperatures on Sunday will range from around 70 near the coast to the upper 70s to mid 80s for the Inland Empire with the lower deserts around 100. Model clusters show the growing spread in the high temperature guidance for early next week are mostly due to differences in the strength of the low pressure system near the West Coast. Those that are weaker are warmer for southern California while those that maintain a stronger low pressure system near the coast are cooler for southern California. Overall, the guidance shows a gradual warming trend for early next week. The marine layer will deepen over the weekend with coastal low clouds extending inland across most of the valleys for early Saturday and onto the coastal slopes of the mountains for early Sunday. The marine layer is expected to begin decreasing in depth early next week with night and morning coastal low clouds not spreading as far into the valleys. && .AVIATION... 030430Z...Coast/Valleys...Low clouds based 1500-2000 ft MSL have redeveloped over coastal San Diego County this evening. Clouds expand northward and inland overnight, eventually reaching into portions of the Inland Empire by 12z. 70% chance for cigs at KONT and 50% at KSBD. Minor vis reductions (4-6SM) for elevated inland valleys. Scattering to the coastline by 17-18z Wed. Low clouds return to coastal areas Wed evening with lower bases around 1000- 1500 ft MSL. Less inland extent Wednesday night with clouds remaining confined to coastal areas and western valleys. Mountains/Deserts...Mostly clear skies and VFR conditions through Wednesday evening. . && .MARINE... No hazardous marine conditions are expected through Sunday. && .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...17 AVIATION/MARINE...KW

