Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
679 FXUS66 KSGX 110500 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 900 PM PST Mon Nov 10 2025 .SYNOPSIS... Patchy dense fog is expected for the coast and western valleys tonight into Tuesday morning. Cooler conditions are likely for the middle to end of the week. A windy and wet pattern will develop for Thursday through Saturday. Dry conditions will likely return for Sunday, with additional potential for rain early next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... This evening...The marine layer remains very shallow with low clouds and fog developing in the coastal areas of San Diego County, spreading locally into the western portions of the inland valleys. Locally dense fog is forming on the coastal mesas and could increase in areal coverage overnight. Development of low clouds/fog is being hampered by mid and high clouds moving in from the west so the amount of low clouds and fog is somewhat in doubt. Sfc pressure gradients are still offshore but are trending weaker. The offshore flow has weakened significantly and the strongest easterly wind gusts reported this hour are in the 15-20 mph range. From previous discussion... An area of low pressure currently about 1450 miles west southwest of San Diego will slowly begin to move east today. This slow eastward progression will begin to weaken the ridge of high pressure over the area by Tuesday. As the upper level pattern begins to shift, the surface offshore pressure gradient will weaken and begin to transition back onshore. Influence from the offshore flow and a fairly robust high pressure aloft have kept high temperatures a few degrees warmer than yesterday. As the high weakens, conditions will begin to cool for Tuesday. Highs Tuesday will be 3 to 6 degrees cooler than today west of the mountains. Cooler conditions will continue to spread further inland Wednesday. As the low pressure system approaches and the onshore pressure gradient continues to increase for the middle of the week, dense fog will become less likely for coastal locations. Model solutions are coming into better agreement for the incoming low pressure system, particularly when it comes to the onset of the precipitation. Most guidance is indicating that precipitation will begin as early as Thursday afternoon and evening with decreasing chances for showers for Friday afternoon into Saturday. Through Friday, NBM has a 70 to 90 percent chance for one-quarter inch or more of rainfall from the coast to the mountains with a 25 to 45 percent chance of 2 inches or more for the mountains. When the cold front initially passes through Thursday evening/overnight there are chances of isolated thunderstorms to develop. Snow levels above 10000 feet will lower to 6000 to 6500 feet by Friday morning. For early Friday, the NBM 25th percentile snow level is 4500 to 5500 feet with the 75th percentile snow level 6000 to 7000 feet. NBM for Big Bear has a 60 percent chance for 1 inch or more of snowfall and a 15 percent chance for 6 inches or more. Winds are also expected to increase for Thursday into Friday. Gusts of at least 50 to 60 mph are looking likely over the mountains and into the deserts, with the potential for wind speeds to increase as we get closer especially for wind prone locations. NBM chances for precipitation are slow to taper off into Saturday, with rainfall for Friday afternoon through Saturday expected to be scattered in coverage. Dry conditions are expected by Sunday, with high temperatures remaining around 5 degrees below average. Ensemble guidance is indicating the potential for additional precipitation early next week. && .AVIATION... 110400Z...Coasts/Western Valleys...Low clouds 300-600 ft MSL will continue to become more widespread along SD/Orange Co coasts into inland areas as far as 10 miles inland. VIS reductions 1-4 SM along coastal areas with dense FG (1/2 SM or less) along elevated coastal terrain and in western valleys initially. Bases expected to lower slightly overnight, with chances for dense FG with vis <1 SM around 40% after 08Z. Increasing high clouds AOA 20k ft will lead to periodic, random scattering out in patches overnight. Clouds and FG retreat to the coastline 15-17Z Tue. Low clouds will rise slightly Tues evening to 400-700 ft MSL and push ashore after 12/03Z. Inland Valleys/Mountains/Deserts...VFR conditions and increasing SCT- BKN high clouds AOA 20 kft through Tuesday. && .MARINE... Expecting areas of fog with visibility 1 SM or less overnight through late morning Tuesday. See the Marine Weather Statement. A storm system is expected to bring stronger southwest becoming northwest winds and higher seas for late Thursday through Friday. Gusts of 20 to 30 knots expected with steep and choppy seas 7 to 10 feet. There is also a slight chance of thunderstorms Thursday evening. && .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