976 FXUS66 KSGX 151606 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 906 AM PDT Sun Jun 15 2025 .SYNOPSIS... Heat will peak today, with a gradual cooling starting Monday and continuing through most of the week. Night and morning low clouds and fog can be expected each day along the coast, reaching into portions of the valleys for the middle to end of the week. Breezy west winds across the mountains and deserts each afternoon and evening, strongest on Monday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Visible satellite this morning was showing low clouds rapidly retreating to the beaches. High resolution guidance continues to show clear skies will prevail this afternoon from the beaches to the deserts. Low clouds are expected to remain persistent each night and morning for the coast early this week, with areas of locally dense fog possible. The marine layer is expected to deepen for the middle to end of next week as a more amplified trough of low pressure approaches the West Coast. Today is expected to be the peak of the heat with high temperatures mostly 5 to 10 degrees above average. Widespread moderate HeatRisk will impact the inland valleys, mountain foothills, and High Desert today, with moderate to locally major HeatRisk in the low desert. Make sure you`re staying hydrated and seeking shade if you`re spending time outdoors. If possible, avoid strenuous outdoor activity during the hottest part of the day (12pm-5pm). The ridge of high pressure over us today will begin to flatten Monday as an upper level trough moves inland across the West Coast. That will kick off a gradual cooling with highs Monday a few degrees cooler than today and additional cooling into Tuesday. In addition to a few degrees of cooling, onshore flow will strengthen for the beginning of the week. That will bring breezy west winds on the desert mountain slopes, below the passes, and into the deserts during the afternoons and evenings. Strongest winds are expected Monday with gusts 30 to 45 mph, locally up to 50 mph through the San Gorgonio Pass. Global ensemble clusters show a brief rebound in the ridge for Wednesday, which will bring a few degrees of warming to inland areas. Highs will be mostly 5 to 10 degrees above average again. NBM chances for the Inland Empire to exceed 100 degrees is 10 to 20 percent, locally up to 60 percent for eastern portions of the Inland Empire. In the low desert, NBM has a 40 to 50 percent chance of high temperatures exceeding 110 degrees. The warming on Wednesday will be short lived as there is good ensemble agreement in a more amplified trough moving into the Pacific Northwest Thursday through the weekend. While there is still some uncertainty in the finer details cooler conditions, increased winds, and a deeper marine layer can be expected for the end of the week. There is high confidence in dry conditions with this passing trough. && .AVIATION... 151525Z....Coast/Valleys...Low clouds based around 400-800ft MSL with tops near 1500ft MSL are beginning to clear western valleys this morning. This pattern will continue with full clearing to the coast expected by 17-18Z. Low clouds redevelop tonight around 06z Monday initially across southern coastal San Diego County. Clouds spreading 5-10 miles inland and northward into southern Orange County by 09-12z Monday. This will yield a 35% chance of BKN cigs VCTY KSNA. Bases likely a touch lower than this morning, around 300- 600ft MSL. .Mountains/Deserts...FEW-SCT high clouds and mostly unrestricted VIS prevail through early Monday. && .MARINE... Wind gusts up to 20-25 kts possible in the outer waters Monday afternoon, primarily near San Clemente Island. Otherwise, no hazardous marine conditions are expected through Thursday. && .BEACHES... A 3 foot southerly (190 degrees) swell at 17-18 seconds will continue to produce elevated surf of 3 to 6 feet with local sets up to 7 feet, primarily for Orange County and northern San Diego County beaches. A Beach Hazard Statement remains in effect through late Sunday evening. Swell and surf heights wane late Sunday into Monday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement through this evening for Orange County Coastal Areas. PZ...None. && $$ PUBLIC...CO AVIATION/MARINE/BEACHES...APR