A low pressure system moving to near the coast will bring precipitation for late Tuesday night and Wednesday, stronger and gusty south to southwest winds for the mountains and deserts for Tuesday night into Wednesday night with high temperatures falling below average on Wednesday. Warmer and drier for Friday and Saturday, then more widespread and heavier precipitation could spread into the area by early next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
(today through Wednesday), High pressure aloft will warm high temperatures today for the mountains a few degrees while a return of onshore flow cools high temperatures for the coast into the western valleys a few degrees. Onshore flow will strengthen for Tuesday into Wednesday as a low pressure system moving toward the California coast moves to near the coast for Tuesday night and Wednesday. South to southwest winds will strengthen for the mountains and deserts beginning on Tuesday. The strongest winds are expected along the desert slopes of the San Bernardino County mountains into the adjacent deserts for late Tuesday night through Wednesday morning with gusts to 55 to 65 mph on the lower desert slopes of those mountains.
More significant cooling of high temperatures is expected for Tuesday and for Wednesday. High temperatures will remain above average on Tuesday with high temperatures as much as 5 degrees below average for the valleys and coastal slopes of the mountains on Wednesday. High temperatures on Wednesday will be mostly in the lower to mid 60s for the coast and valleys and in the lower to mid 70s for the lower deserts.
Chances for precipitation will increase for late Tuesday night through Wednesday with the most likely time for precipitation during the day on Wednesday. For Orange and southwestern San Bernardino Counties, rainfall could range from one-third to one- half inch near the coast to one-half to locally one inch on the coastal slopes of the San Bernardino County mountains. Amounts will decrease from north to south with as little as one-tenth to one- quarter inch for southern San Diego County. The snow level will rise to around 7000 feet Wednesday morning, then fall to around 5500 feet for late Wednesday night.
(Thursday through Sunday), Some scattered showers could linger into Thursday, mainly near the mountains, with drier weather for Friday and Saturday with daily chances for measurable precipitation for the mountains around 30 percent on Thursday and 15 percent on Friday and on Saturday. More widespread and heavier precipitation could develop by early next week and continue into the middle of next week. For Lytle Creek in the eastern San Gabriel Mountains, the chance for 3 inches or more of rainfall increases to 30 percent for next Sunday through Monday, and 45 percent for next Tuesday through Wednesday.
091030z. Mostly clear and VFR conditions today into tonight. Increasing chance of low clouds to impact coastal airports after 06Z tonight into Tuesday.
No hazardous marine conditions are expected today through Friday.
Ca, None. PZ, None.
