Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
673 FXUS66 KSGX 302138 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 138 PM PST Sun Nov 30 2025 .SYNOPSIS... Dry and cool today. The marine layer deepens into Monday for more widespread low clouds tonight into Monday morning. Weak to locally moderate Santa Ana winds develop Monday and weaken Tuesday with warmer and drier weather. Precipitation chances continue to decrease with only a few stray light showers possible Wednesday. Chances increase for another round of weak to moderate Santa Ana winds late Wednesday into Friday. Gradual warming Thursday through the weekend with highs near seasonal normals. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Current satellite and 500 mb mesoscale analysis shows a stout shortwave trough digging through Nevada with an associated 500 mb jet of about 50-70 kts dipping into southern Nevada and southeastern California. Breezy westerly onshore flow is allowed to develop this afternoon as a result, particularly felt across higher elevations including the high deserts and the mountains/adjacent desert mountain slopes. Wind gusts of 25-35 mph expected in these areas, with up to 35-45 mph gusts on mountain peaks. The increase onshore flow and presence of the trough allowed for a deeper marine layer and a foggy/cloudy morning along the coast. Temperatures this afternoon peak a few degrees cooler than yesterday, generally in the 60s to low 70s for most. With continued onshore flow this evening into the overnight hours, the marine layer remains fairly deep with inland cloud cover extent expected through inland valleys again. Cooler air spills into the Great Basin tonight into Monday behind the aforementioned trough, serving to strengthen the offshore pressure gradient featuring a period of weak to locally moderate strength Santa Ana winds. Northerly/easterly offshore winds expected to pick early Monday morning, peaking Monday afternoon, and weakening Monday evening. Wind gusts of 25-35 mph stretch into portions of the Inland Empire and inland valleys of San Diego and Orange Counties, with the strongest gusts of 35-45 mph focused in and just below mountain passes. Temperatures tick back up some tomorrow, with dry desert air pushing into the coastal basin from the weak Santa Anas. The offshore winds will push the marine layer out early Monday morning, keeping it offshore into Tuesday as well. The trough and surface high kick out fairly quickly Monday night, with onshore flow returning for Tuesday. Temperatures moderate some as a result, with similar highs to today. Wednesday through Late Week... The next trough digs southward from the Pacific Northwest through California Tuesday into Wednesday, and while there has been a fair amount of uncertainty regarding the track/evolution of this system, models are now coming into better agreement. Ensemble consensus now generally agrees this trough will not be as deep as some members hinted at the possibility of the past few days, with the base of the trough passing over the Mojave Desert and kicking eastward into AZ/NM by Thursday morning. This track favors a much drier solution with PoPs now falling to a meager 10-20% with a slight chance of light showers Wednesday afternoon, primarily across San Diego County. Any precipitation amounts expected to be light and largely negligible. The other consequence of the anticipated track of this mid-week trough will be yet another period of offshore winds. While there is still some uncertainty in the strength, weak to moderate Santa Ana winds similar or a touch weaker than Monday`s event expected late Wednesday and likely persisting through Friday. The marine layer looks to return Wednesday morning following Tuesday`s onshore flow, but should be weakened and largely restricted to the coasts or just offshore through late week with the persistent offshore flow. As for temperatures, Wednesday looks to be the coolest day of the week with highs about 5 degrees below normal. Gradual warming and drying follows through the end of the week with the weak offshore pattern. && .AVIATION... 302030Z....Coasts/Valleys...Patchy low clouds with bases of 1300- 2000ft MSL move ashore as early as 00-01Z Monday. Intermittent CIGs at KSAN prior to this. Some low clouds will likely filter into the Inland Empire some time after 04z Mon. Bases will rise beginning around 10-11z as offshore winds kick in, to around 1800-2400ft MSL or higher, and clouds will quickly push back towards the coastline. Clouds should clear to the coast by 18z Mon. .Mountains/Deserts...VFR conditions are expected through the TAF period. Strong surface winds gusting 25-35 kt, up to 45 kt through wind-prone passes, at times in the deserts and eastern mountain slopes, prevailing through this evening. Moderate up/downdrafts expected in the vicinity of the mountains. Winds becoming offshore and breezy after 12Z Monday morning for the coastal foothills, eastern valleys, and Inland Empire, with local areas of LLWS possible. && .MARINE... No hazardous marine conditions are expected through Friday. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...Munyan AVIATION/MARINE...Zuber