Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
791 FXUS66 KSGX 010528 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 928 PM PST Sun Nov 30 2025 .SYNOPSIS... 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 a little warmer and drier weather. Precipitation now seems unlikely this week. Chances increase for another round of weak to moderate Santa Ana winds late Wednesday into Friday. Gradual warming Thursday into next weekend with highs near seasonal normals. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... The marine layer is much deeper this evening and low clouds have already spread about 15 miles inland, covering almost all of the coastal areas and portions of the inland valleys. With onshore pressure gradients, the low clouds are expected to spread farther inland before developing offshore flow begins to clear out the low clouds early Monday morning. A sfc high following a trough into the Great Basin tonight will produce the offshore flow Monday but the strongest winds will be fairly localized to the wind-prone areas due to a lack of upper level support. From previous discussion... Northeast to east winds are expected to pick up 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 rise slightly 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 move east fairly quickly Monday night, with onshore flow returning for Tuesday. Temperatures moderate somewhat as a result, with similar highs to today. Wednesday through Late Week... The next trough moves 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 indicated over the past few days, with the base of the trough passing over the Mojave Desert and moving eastward into AZ/NM by Thursday morning. This track favors a much drier solution with precipitation chances falling to a meager 10-20% with a slight chance of light showers Wednesday afternoon, primarily across San Diego County. Any precipitation amounts will be light and largely not measurable. 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... 010400Z....Coasts/Valleys...Patchy clouds based 1700-2200 ft MSL will continue to spread along the coast into inland areas, including into parts of the Inland Empire. 30-40% chance for CIGs at KONT/KSBD 05-09Z this evening. Winds become offshore for coastal foothills into parts of the eastern valleys early Mon morning, eroding clouds out of inland areas as early as 10-13Z, coastal areas 13-16Z. Local east/northeast wind gusts 20-35 kt in parts of the IE after 16Z through the evening, with local areas of LLWS possible. 20% chance for low clouds based 700-1500 ft MSL for coastal areas Mon evening. .Mountains/Deserts...VFR conditions are expected through the TAF period. Winds becoming offshore and breezy after 10Z for the coastal mtn slopes and foothills, with east/northeast wind gusts locally 25- 40 kts, and local areas of LLWS possible. && .MARINE... No hazardous marine conditions are expected through Friday. && .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...PG AVIATION/MARINE...CSP