Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
431 FXUS66 KSGX 112057 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 157 PM PDT Sun Aug 11 2024 .SYNOPSIS... Thunderstorms over the mountains, deserts and even the far inland valleys will gradually dissipate this evening. A slight chance of thunderstorms returns 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... Thunderstorms got started in southern San Diego County before midday and several other strong thunderstorms have developed over the mountains. Some of the weakening storms have spilled into the inland valleys of southern San Diego County. A couple mountain storms could spill into the adjacent far inland valleys. Some storms could produce flash flooding and/or strong, gusty winds. Expect more strong storms to develop and dissipate mainly in the mountains and adjacent valleys and deserts before finishing up by sunset. Meanwhile, a coastal eddy has brought some low clouds to coastal southwest San Diego County, and the coastal cloud coverage tonight should be more widespread. Temperatures have decreased in the mountains and deserts compared to yesterday, except the valleys are just as warm, and it has felt more muggy today in all areas. 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... 112234Z...Coast/Valleys...Mostly clear skies with some FEW-SCT clouds near 20K ft MSL. ISO TSRA drifting into foothills and adjacent valleys west of the mountains this afternoon and early evening. Patchy to areas of low clouds are expected to move into the coastal areas overnight. Only moderate confidence in timing and coverage for cigs at coastal TAF sites later tonight, mainly after 06Z Mon with bases near 1000 ft MSL with tops to near 1200 ft MSL. Mountains/Deserts...SCT-BKN clouds with bases around 10,000 ft MSL develop after 16Z, followed by scattered TSRA between 19Z Sunday and 03Z Monday. Gusty and erratic winds possible near storms as well as MOD UDDFS. && .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...MM AVIATION/MARINE...Small