Area Forecast Discussion
Issued by NWS San Diego, CA
Issued by NWS San Diego, CA
659 FXUS66 KSGX 161109 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 409 AM PDT Fri Aug 16 2024 .SYNOPSIS... While monsoonal moisture is expected to increase for today into this weekend, dry weather is expected to continue through Sunday. After slight drying for Sunday and Monday, an additional influx of moisture is expected to bring a slight chance of afternoon thunderstorms for the mountains into the deserts for the middle of next week, peaking around Wednesday. After a few degrees of cooling on Saturday, warming is expected for Sunday through Tuesday with Tuesday high temperatures around 5 degrees above average to locally 5 to 10 degrees above average for portions of the inland valleys. Areas of night and morning low clouds will spread locally inland into coastal areas. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (Today through Sunday)... There is a weak coastal eddy with coastal low clouds spreading northward along the southern California coast and locally inland along the coast. That eddy is expected to persist into Saturday morning and then dissipate on Saturday. The local NAM-bounded WRF shows slowest coastal clearing for this afternoon. Outflow from thunderstorms over northwest Mexico has been spreading westward and northwestward and dissipating. Not much change in high temperatures is expected for today with Saturday a few degrees cooler and Sunday a degree or two warmer. An influx of monsoonal moisture is expected for today into Saturday, followed by slight drying for Sunday and Monday. While some afternoon clouds over the mountains are expected, any rainfall is unlikely with NBM chances for measurable rainfall mostly 5 percent or less for the mountains for each day through the weekend. && .LONG TERM (Monday through Thursday)... After slight drying on Monday and Tuesday, monsoonal moisture increases again for Tuesday and Wednesday with NBM increasing the surface dewpoint at Thermal to 68 on Wednesday morning. For Big Bear, NBM chances for measurable rainfall are greatest on Wednesday at 13 percent with chances for thunderstorms greatest on Wednesday and Thursday at 16 percent. Warming is expected for Monday and Tuesday with Tuesday high temperatures around 5 degrees above average, except locally 5 to 10 degrees above average for portions of the inland valleys. This is expected to be followed by high temperatures a few degrees lower each for Wednesday and Thursday with the influx of moisture. && .AVIATION... 160930Z...Coast/Valleys...Stratus with bases 900-1300 ft MSL and tops to 1600 ft MSL continuing to spread into the coastal areas and locally 10-15 mi inland this morning. Local vis 3-5 SM in BR/HZ over the higher coastal terrain, locally 1 mi or less on the coastal mesas. Clouds and vis restrictions clearing over land 15-17Z and at the coast 17-19Z. Low clouds redeveloping near the coast around 17/03Z, spreading 10-15 mi inland again after 17/06Z. Little change in bases/tops tonight into Sat morning. Otherwise mostly clear with unrestricted vis through Sat morning. Mountains/Deserts...FEW-SCT Cu developing over the mountain crests this afternoon, dissipating by sunset. Otherwise mostly clear with unrestricted vis through Sat morning. && .MARINE... No hazardous marine conditions are expected through Tuesday. && .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...SS