921 FXUS66 KSGX 122019 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 119 PM PDT Thu Jun 12 2025 .SYNOPSIS... Subtle warming will occur across inland areas through the weekend as an area of high pressure strengthens over the desert southwest. The marine layer will remain quite consistent, with night and morning low clouds near the coast into the western valleys. Weak troughing and ridging across the Southwest next week will lead to minor fluctuations in high temperatures. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Early afternoon temperatures are near the 100 degree mark across the lower deserts with highs in the 80s across the Inland Empire and San Diego County foothills. Onshore winds will continue to be breezy out of the west across mountain passes into the adjacent deserts near 25-40 MPH through this evening. A stubborn marine layer is present as clouds claw the beaches. Minor clearing may occur across parts of Orange County later this afternoon with coastal SD County more likely to stay under the clouds. The marine layer depth looks to remain fairly unchanged over the next couple of days, where clouds can be expected to fill much of the coastal basin each morning. An area of high pressure over Baja California will strengthen and push northward across the Southwest by the weekend. 850 mb temperatures will increase around 30C by Sunday. As a result of this, warmer temperatures can be expected away from the coast with highs 5 to 10 degrees above normal. High temperature probabilities have gone slightly downward over the past couple of days, but we will still be seeing hot weather across inland valleys and desert areas with moderate to locally high heat risk. There is high confidence in seeing temperatures above 110 degrees in the lower deserts and moderate confidence in seeing highs reach 100 degrees for places in the Inland Empire and populous areas of the high desert. A weak trough will cross California by early next week, which will aid to cool temperatures closer to normal. Night and morning low clouds will still continue at the coast and western valleys. Another area may gain strength by the middle of next week, which would lead to another subtle warm up. && .AVIATION... 122000Z....Coast/Valleys...Low clouds based around 1300-1600 feet MSL with tops to around 2200 feet are present along immediate coastal areas, where they will remain with only intermittent, if any, clearing through the day. Low clouds will begin to move inland again after 00Z, then into valleys early Friday, but not as extensively as this morning. Bases 600-1000 ft MSL with vis reduced 0-5SM over higher coastal terrain between these levels. Clouds clearing 15-17Z Fri for inland areas and 18-20Z for coastal regions. Clouds will again linger along the beaches, but with better chances for brief clearing at KCRQ (70%) and moderate chances at KSAN (40%). Otherwise...Mostly clear skies and unrestricted vis today and tonight. && .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...APR AVIATION/MARINE...CP