Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
476 FXUS66 KSGX 191230 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 430 AM PST Wed Nov 19 2025 .SYNOPSIS... Some showers will continue over the coastal waters for this morning with a slight chance of showers over the mountains for this afternoon. The next low pressure system from the northwest will bring more widespread showers for Thursday night and Friday. With snow levels lowering to around 6000 feet for late Thursday night, there could be heavy snowfall in the mountains above 6000 to 6500 feet. Some showers could linger into the weekend. Then drier and warmer next week with high temperatures warming to within a few degrees of average for Tuesday and Wednesday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (Today through Friday)... The slow-moving low pressure system centered over the southern California bight will begin to accelerate to the east later today and tonight as the next low pressure system from the northwest nears the West Coast by early Thursday morning. Some showers have continued over the coastal waters overnight, the result of instability from the cold air aloft over the relatively warm sea surface temperatures. These showers will continue into this morning. There is also a slight chance of showers for this afternoon, mainly over the mountains. Some showers may develop late tonight over the inner coastal waters and spread inland into coastal areas for late tonight into Thursday morning. Some light showers from the next low pressure system may begin to spread into portions of southwestern California during the day on Thursday with more widespread showers along with a slight chance of thunderstorms spreading into the area on Thursday night with showers continuing into Friday. The snow level will rise to around 7000 for late Thursday afternoon, then fall to around 6000 for early Friday morning, before rising to around 6500 feet for Friday evening. Rainfall could range from around one-half inch near the coast to 1 to 2 inches for the mountains. Chances for one inch or more of rainfall or liquid-equivalent above the snow level through Friday night ranges from around 25 percent near the coast to 45 to 55 percent in the mountains. The NBM deterministic snowfall for Big Bear of just under 10 inches is near the 60th percentile of the distribution. A Winter Storm Watch for mountain elevations above 6000 or 6500 feet may be needed for Thursday night into Friday. && .LONG TERM... There remain model differences in the placement and movement of the closed upper level low pressure system for the weekend impacting whether and where some showers might linger into the weekend. For next week, drier and warmer weather is expected with high temperatures on Tuesday and Wednesday within a few degrees of average. && .AVIATION... 191030Z...SCT-BKN clouds generally 3500-8000 feet MSL today. Isolated SHRA over the ocean through 14Z. Patchy fog in valleys locally reducing vis 0-1SM through 16Z. Building cumulus around 9000 feet mainly over mountains, with SHRA 19-02Z. Increasing clouds around 2500-3500 feet MSL in coast and valley areas after 06Z into Thursday. && .MARINE... No hazardous marine conditions are expected through Thursday. Southerly winds will increase late Thursday as the next storm system arrives, with the potential to bring hazardous winds and seas. There is also a slight chance of thunderstorms late Thursday through Thursday night. Any thunderstorm could bring lightning, gusty winds, choppy seas, and a waterspout. No additional hazardous marine conditions are anticipated Friday through Sunday. && .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...17 AVIATION/MARINE...MM