Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
690 FXUS66 KSGX 052027 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 127 PM PDT Thu Jun 5 2025 .SYNOPSIS... There is a slight chance of showers and thunderstorms for this afternoon for the San Bernardino Mountains and the High Desert. The marine layer will stay a similar depth into Friday with patchy drizzle overnight and Friday morning, before becoming shallower over the weekend. A gradual warming trend is expected through the weekend, with the potential for continued warming into early next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Visible satellite at 1 PM was showing areas of low clouds lingering along portions of the coast and in the valleys, mainly in San Diego County. It was also showing some cumulus cloud development over the mountains and in the High Desert. The marine layer is expected to be a similar depth as last night tonight into Friday morning, with patchy drizzle likely west of the mountains. The marine layer is expected to get shallower over the weekend as higher pressure tries to build from the south. Slight chances (15-20 percent) of showers and thunderstorms has been maintained in the forecast for this afternoon for the San Bernardino mountains and High Desert. HREF is indicating rainfall rates will remain less than 0.30 inches per hour. The atmosphere continues to dry out Friday through the weekend, with no additional chances of showers/thunderstorms for at least the next week. Conditions will warm into the weekend with increasing potential for warming to continue into early next week. Latest guidance has trended warmer from the valleys to the deserts for early next week. Ensemble guidance is in better agreement that the weak low pressure system off the California coast will weaken and move to the west with high pressure to the south expanding into Southern California. NBM chances for high temperatures to exceed 110 degrees in the low deserts are the highest on Monday at 15 to 35 percent. Chances for high temperatures to exceed 105 degrees are highest Sunday and Monday at 80 to 95 percent. West of the mountains, chances of exceeding 100 degrees for Monday and Tuesday are localized to the eastern Inland Empire near 15 percent. Chances of exceeding 95 degrees are 10 to 25 percent for the valleys, with local areas in the eastern portion of the Inland Empire closer to 65 percent on Monday and Tuesday. Temperatures will decrease a few degrees on Tuesday, with ensemble guidance indicating a continued decrease in temperatures for Wednesday and Thursday. By next Thursday, June 12, 80 percent of ensemble solutions show an incoming trough of low pressure will push the ridging east. Within that 80 percent, most of the uncertainty is surrounding the amplitude of the incoming trough. && .AVIATION... 052000Z....Coast/Valleys...Clearing has mostly occurred across the Inland Empire and Orange County, with slower clearing for San Diego County. VIS is slowly improving and is above 4SM with bases 2100- 2700ft MSL. Some areas, especially southwestern SD County may not see full clearing today (50% confidence in not clearing). Low clouds push inland again after 00Z with very similar coverage, bases, vis, and patchy -DZ overnight into Friday morning, with similar slow clearing late Friday morning. Mountains/Deserts...Mostly clear through tonight. Cumulus and ISO SHRA/TSRA based at 10,000ft MSL 20-01Z over mountains and high desert. && .MARINE... No hazardous marine conditions are expected today through Monday. && .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...Zuber