Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
064 FXUS66 KSGX 290542 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 942 PM PST Fri Nov 28 2025 .SYNOPSIS... Relatively quiet weather expected through early next week with weak offshore winds Saturday and again Monday. Night and morning coastal low clouds and fog will increase in coverage and spreading a little farther inland each night through the weekend. Next potential storm system will occur Wednesday into Thursday, but confidence in rainfall continues to be low, with increasing chances chances for dry weather and yet another round of offshore flow mid week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... This evening, the marine layer remains quite shallow in spite of the troughing/cyclonic flow and lower heights aloft. The low clouds have increased in coverage from this time last night and high resolution models expect that trend to continue, with low clouds and fog spreading a little farther inland. Sfc pressure gradients are weak but trending onshore. Today high temperatures, especially in the coastal areas, were several degrees lower than yesterday afternoon. Today`s high temp at San Diego International Airport was 12 degrees lower than yesterday. From previous discussion... The ridge that had previously been overhead has been flattened out with a shortwave trough moving from the Pacific Northwest into the Great Basin this weekend. Ultimately, the result of this trough will be minimal, with weak offshore winds in the deserts and mountain passes, and onshore flow dominating for the coasts and valleys. The onshore flow and a weak coastal eddy tonight will help clouds fill in better, likely pushing ashore overnight, with patchy fog expected along elevated coastal terrain and portions of western valleys. Otherwise, relatively benign weather expected through the weekend with mostly clear skies and temperatures within 5 degrees of seasonal norms. Yet another inside slider digs through the Great Basin Sunday into Monday, reinforcing the offshore gradient and leading to another round of offshore winds. This event looks to be a touch stronger than Saturday`s offshore flow with easterly/northerly winds extending into the inland valleys, however, the event is still rather weak. The timing of the next disturbance is in the Tuesday-Wednesday window, though a great deal of uncertainty remains in the depth of the trough, with reasonable spread in the ensembles varying from a trough deep enough to bring showers to the area, to a shallower trough that could bring another round of offshore flow with no precipitation. A driving factor in the evolution of this trough and it`s forecast depth is a cut-off low well off the southern California coast early-mid next week. If the cut-off low stays close and interacts with the trough, precipiation chances become more likely and offshore flow will be more limited. Ensembles are fairly split in precipitation, with about a 50/50 chance for showers. Even still, should the rainy solution pan out, rainfall totals will be light, generally 0.1" or less, locally up to 0.25" on the coastal slopes. Snow levels between 6500-7000ft, so a few flakes are possible in the mountains if precipitation occurs. The most certain aspect of this forecast will be temperatures about 5 to 10 degrees below average. && .AVIATION... 290400Z....Coasts/Valleys...Low clouds based 700-1100 ft MSL have developed offshore and locally along coastal regions. Clouds will spread through the coast and inland to 10-15 miles overnight. Localized VIS reductions to 4-6 SM for parts of the coast, 1-3SM for elevated coastal terrain. Cigs expected to rise slightly overnight. Low clouds clearing to the 15-17Z. Low clouds 800-1200 ft MSL redevelop and push ashore after 30/04Z. .Mountains/Deserts...VFR conditions expected through the TAF period. && .MARINE... No hazardous marine conditions are expected through Wednesday. && .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