Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
069 FXUS66 KSGX 070940 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 240 AM PDT Sat Jun 7 2025 .SYNOPSIS... A deep marine layer with patchy drizzle this morning, then a shallower marine layer Sunday through much of next week. Temperatures warm through the weekend, peaking Monday and Tuesday, before a slow cooldown into the end of next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Marine layer low clouds continue to fill in west of the mountains this morning. Drizzle has been occurring, most widespread over San Diego County where some valley locations have managed to pick up measurable precipitation. Low clouds will be slowly clear inland later this morning, but coastal areas will likely remain cloudy through the day. We remain wedged between a closed low off the Central CA coast and a building upper level high over northern Mexico today, which will slowly expand northwestward into Sunday. This will bring warming inland where highs will be around 3-5 degrees above normal today and around 5-8 degrees above normal on Sunday. The marine layer remains sufficiently deep with continued onshore flow to moderate temperatures west of the mountains where highs will remain closer to normal. The closed upper low becomes an open wave and moves by to the north as the upper ridge amplifies to our west, bringing continued warming Monday and Tuesday. The marine layer becomes more shallow with low clouds and patchy fog confined to the coastal areas and far western valleys each night and morning, though clearing at the beaches will still be somewhat limited. In terms of temperatures, by Tuesday there is a 15-25% chance of high temperatures of 100 degrees or more in the far inland portions of the Inland Empire and a 40-60% chance in parts of the high desert. For the low deserts, there is a 15-40% chance of high temperatures of 110 or higher. The ridge begins to flatten in response to a weak short wave moving by to the north on Wednesday, resulting in minor cooling. A second wave begins to drop south on Thursday, then a long wave trough amplifies along the West Coast Friday into next weekend. This will bring more significant cooling, breezy conditions in the mountains and deserts, and a deeper marine layer with low clouds extending into the inland valleys once again. && .AVIATION... 070930Z....Coast/Valleys...Low clouds based at 1200-2000 ft MSL with tops to 3000 ft MSL have already filled most of the coastal basin. Patchy -DZ will continue through 15z allowing for vis reductions 3-5 SM in BR and occasional cigs lowering to 700-900 ft MSL. Clouds clear from the Inland Empire 16-18Z and from Orange County 17-19Z, with cigs likely remaining in San Diego County along the coast and up to 15 miles or so inland through the day yet again. Low clouds begin to push inland again after 00z Sunday and should eventually fill most if not all of the coastal basin. Slightly lower bases expected along with vis reductions 3-5 SM for elevated valleys including the IE. Mountains/Deserts...Mostly clear skies and unrestricted vis through Saturday night. && .MARINE... No hazardous marine conditions are expected today 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...SS AVIATION/MARINE...KW