Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
716 FXUS66 KSGX 120406 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 906 PM PDT Sun Aug 11 2024 .SYNOPSIS... There is a slight chance of thunderstorms in southeast San Diego County Monday afternoon. Dry and seasonal weather is expected into next weekend. Patchy coastal low clouds and fog will increase Monday and Tuesday and continue each night and morning. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... It was an active afternoon and early evening, mainly for the San Diego County mountains and deserts. In San Diego County multiple strong thunderstorms developed, which resulted in areas of flash flooding on the desert mountain slopes and into the San Diego deserts. Thunderstorms in San Diego county produced 8953 discharges of lightning and 713 cloud to ground strikes. A few thunderstorms also developed in the Riverside and San Bernardino mountains. In the Riverside mountains there were 637 discharges and 43 cloud to ground strikes and in the San Bernardino mountains there were 61 discharges and one cloud to ground strike. A rainfall summary has been headlined on our weather.gov/sandiego homepage, with multiple locations in the San Diego county mountains picking up over an inch of rain. Dry conditions are expected overnight with areas of high clouds lingering in and west of the mountains through at least midnight. Areas of low clouds may redevelop at the coast by early Monday but coverage is expected to be patchy. From previous discussion issued 2 PM August 11, 2024... The inverted monsoon trough overhead today will fade as a low pressure trough off the Pac northwest coast will amplify over the next couple days. This will effectively sweep away the monsoonal moisture, but enough residual moisture and instability remain Monday over southeastern San Diego County for a slight chance of tstorms Monday afternoon. The amplifying trough to the north will help rebuild the marine layer. Coastal clouds will become more uniform, extensive and longer lasting, but still restrained to nights and mornings. The trough will also boost winds through mountain gaps into deserts during the afternoons and evenings, with top gusts exceeding 40 mph. Temps will settle down to around normal. Some model guidance suggests an increase in monsoonal moisture again next weekend, but no credible chance of precipitation yet. Expect seasonal and dry conditions to remain with very little day to day variation this entire week. && .AVIATION... 120340Z...Coast/Valleys...Patchy low clouds with bases 900-1100 ft MSL will move into the coastal areas overnight, with a 50-60 percent chance of CIG impacts at coastal TAF sites between 10Z and 15Z. VIS locally reduced on higher coastal terrain. Low clouds clearing to the beaches 16Z-17Z. Otherwise, SCT-BKN clouds at or abv 10,000 ft MSL through tonight. Mountains/Deserts...SCT-BKN clouds with bases at or abv 10,000 ft MSL through tonight && .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...CO/MM AVIATION/MARINE...PG