Trinity Mountain Resort Snow Report

286 FXUS66 KSGX 240537 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 1037 PM PDT Wed Sep 23 2026 .SYNOPSIS... Warmer conditions through Saturday with moderate HeatRisk for the coast and western valleys on Friday and Saturday. Night and morning low clouds and fog will stay confined to the coastal areas for the next few nights. There is a a slight chance of showers and isolated thunderstorms over the mountains Thursday afternoon. Cooler conditions expected Sunday and Monday, with potentially warmer conditions next Tuesday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... ...UPDATED AVIATION DISCUSSION... Most locations will see an increase in temperatures each day through Saturday, with high temperatures 5 to 7 degrees above average for inland locations and 7 to 12 degrees above average for the coast. Overnight lows will increase to the mid- 60s to 70 west of the mountains and in the upper 70s to low 80s in the low desert. Moderate HeatRisk is expected along the coast Friday and Saturday and in the low deserts for the second half of the week. Moderate HeatRisk has the most impacts on those sensitive to heat, especially those without cooling/hydration. For Thursday, a closed low lingering to our south will start to move east. This low will draw moisture into Southern California from the southeast increasing chances for precipitation, mainly in the mountains. Latest high resolutions guidance indicates rainfall rates will mostly be 0.20-0.30 inches per hour, where thunderstorms develop rates could be closer to 0.50 inches per hour. There remains a 5-10% chance of thunderstorms over the mountains with the higher chances over the San Diego and Riverside County mountains. For Sunday, an incoming trough of low pressure is expected to move inland across northern California. The low will dig south Monday and be to our east Tuesday or early Wednesday. There is good agreement that temperatures will cool 3 to 8 degrees between Saturday and Sunday and another 2 to 4 degrees for Monday. Additionally cloud coverage will increase. The trough looks like it will pull in moisture from our southwest, but there remains uncertainty in how much moisture will actually get pulled into Southern California. Ensemble members from both the GFS and ECMWF are showing increases in precipitable water and some potential for precipitation. For next Tuesday and Wednesday, the forecast solutions diverge with 60% of solutions showing ridging and 40% maintaining weak troughing. Current forecast follows the NBM and shows a few degrees of warming each day Tuesday and Wednesday. && .AVIATION... 240530Z...Coast/Valleys...Low clouds based near 1500 feet MSL will continue to cover coastal areas and eventually spread into western valleys overnight. Some inland vis reduced 3-5SM. Scatter out Thursday 16-19Z. Low clouds based around 1000 feet MSL to move ashore Thursday eve after 02Z, but in somewhat random fashion. .Mountains/Deserts...mostly clear through Thursday, except for SCT cumulus based near 10 kft over mountains and isolated SHRA/TSRA 20- 01Z Thursday afternoon. Any storm that develops will be capable of producing gusty, erratic winds, lightning, and vis reductions. && .MARINE... No hazardous marine conditions are expected through Monday. && .BEACHES... The combination of a 3 foot swell from 190 degrees on Sunday shifting to 160 degrees for Monday and Tuesday with a 12 to 15 second period coinciding with our bimonthly elevated high tides will increase chances for coastal flooding and erosion. Predicted high tides of 6.5 and 7.0 ft MSL will occur between 10 and 11 AM Sunday through Tuesday. The listed tide predictions have been corrected to reflect current trends in actual tide observations. Surf will be elevated, especially for south facing beaches with sets up to 5 feet on Sunday. Surf heights and direction of the swell remain uncertain for Monday and Tuesday and will be most influenced by the track of Tropical Cyclone Polo. && .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...CO AVIATION/MARINE/BEACHES...MM