Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
048 FXUS66 KSGX 070424 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 924 PM PDT Fri Jun 6 2025 .SYNOPSIS... A deep marine layer persists for coastal and inland areas through Saturday, with a shallower marine layer and valley/inland fog 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... This evening...The marine layer remains quite deep at about 3500 ft. Low clouds already cover San Diego County from the foothills to the beaches and practically all of Orange County. Low clouds are also creeping into southern parts of the IE. The saturated layer remains thick and some locations are reporting drizzle. These conditions are likely to persist into Saturday morning. From previous discussion... A closed upper low off the coast of central CA will likely remain in that general location through Sunday, allowing the thermal ridge axis to extend from WA through NV and into AZ. This will position 850mb temps over coastal and inland areas Monday and Tuesday around 22-24C while deserts will see 850 temps 25-27C. This indicates surface highs may push well above 105F for the Coachella Valley and San Diego deserts by Monday, currently looking to peak on Tuesday with highs potentially at or near 108-110F. Elsewhere, temperatures will be above-normal, especially for inland areas, with 92-96F for the Inland Empire early next week. The ridge shifts eastward Wednesday, but zonal flow aloft sets in, limiting the cooldown for the end of the week. At the same time, multiple shortwaves pass across northern California and Oregon through the end of the week, not expected to do much in the way of precipitation but a slight uptick in wind is possible for the far northern areas, especially the High Desert. A deep low moves down from Alaska on Thursday, with troughing setting in over the area early Friday and into the weekend. High temperatures will continue to fall and the marine layer deepens, returning the region to at or below normal temperatures likely by Friday. Long-range models are pretty well aligned, with the low persisting along the Canadian coastline, with cooler weather potentially prevailing through mid June. Welcome back to June Gloom! && .AVIATION... 070300Z....Coast/Valleys...Low clouds based at 1000-2000 ft MSL with tops to 3300 ft MSL have moved into Orange and inland San Diego counties this evening, and will continue to fill most of the coastal basin by 10Z tonight, with vis reductions over higher inland terrain. Areas of -DZ are expected 09-15Z which will bring periodic 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 remaining in San Diego County along the coast and up to 15 miles or so inland through the day. Low clouds will again spread to similar inland extent with similar to slightly lower bases after 00Z Sun. Mountains/Deserts...Mostly clear skies and unrestricted vis tonight and Saturday. && .MARINE... No hazardous marine conditions are expected today through Tuesday. && .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...PG AVIATION/MARINE...CSP