Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
381 FXUS66 KSGX 180409 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 909 PM PDT Tue Sep 17 2024 .SYNOPSIS... Well below normal high temperatures will continue through Thursday along with a chance for mostly light showers on Thursday and Thursday night. High pressure will bring dry and much warmer weather for the weekend with inland high temperatures warming to around average on Saturday and 5 to 10 degrees above average by Monday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Evening update... Patchy low clouds are lingering along the San Diego County coast and starting to develop across the valleys with clear skies elsewhere. The 00Z KNKX sounding shows a 3.5C inversion based near 3200 ft MSL. Patchy low clouds will continue to form overnight, clearing by late morning. Remainder of the forecast remains on track. Previous discussion... Below average high temperatures will continue through Thursday with high temperatures remaining as much as 20 degrees cooler than seasonal averages. Late Wednesday night and Thursday the next low pressure system will move into the area bringing a 20-30% chance of precipitation to the coast, valleys, and coastal mountain slopes. Any precipitation from this next event is expected to be light, generally a few hundredths up to 0.10 inch. After the frontal passage on Thursday, warming will begin in earnest Friday through the weekend with most locations being near seasonal averages by Saturday afternoon, and 5 to 10 degrees above seasonal averages on Monday. High temperatures for the inland valleys will warm into the mid 80s to lower 90s on Saturday, and 90s to around 100 Monday. For the lower deserts, high temperatures will warm to around 100 on Saturday, and to 102 to 107 on Monday. && .AVIATION... 180330Z...Coast to mountain ridges...Patchy low clouds (based around 2500-3000ft MSL, tops near 3500ft MSL) lingering near and just offshore of San Diego County should gradually leak onshore in the next hour or so, remaining somewhat patchy though, so BKN CIGs may come and go at times overnight. Additional cloud development up against the coastal mountain slopes (also based near 2500-3000ft MSL) expected over the next few hours. Coverage between the foothills and coasts will be very patchy. Local vis reductions 1-3 SM for higher terrain above 2000-2500ft where low clouds intersect with terrain. Clouds will break up and scatter out 17-19Z Wednesday but look to rapidly fill in again Wednesday evening starting 22-00z. Deserts and Desert Slopes... Mostly clear tonight and Wednesday. && .MARINE... No hazardous marine conditions are expected 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...SS AVIATION/MARINE...Munyan