Cooler today with coastal low clouds extending inland across most of the valleys this morning and with gusty southwest to west winds for the mountains and deserts for this afternoon into tonight with the stronger gusts to 45 to 55 mph. Warming for Saturday and Sunday with Sunday high temperatures a few degrees above average near the coast to 10 to 15 degrees above average for inland areas. Greater cooling will spread inland for Monday through Thursday with Thursday high temperatures as much as 10 to 15 degrees below average for the mountains and inland valleys. Coastal low clouds will become more extensive next week and may extend onto the lower coastal mountain slopes for the middle of next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
(today through Sunday), A weak low pressure system centered just west of Point Conception will move quickly inland across the area today. The marine layer has deepened to around 3000 feet with low clouds over the coastal waters extending inland across most of the valleys. There are also a few high clouds.
There will be stronger onshore flow with gusty southwest to west winds for the mountains and deserts for this afternoon into tonight with the stronger gusts to 45 to 55 mph. The strongest gusts will be in the northern Coachella Valley below the San Gorgonio Pass with gusts to 65 mph.
High temperatures today will be a few to around 5 degrees cooler than Thursday for most areas with high temperatures for the coast and valleys mostly a few to around 5 degrees below average with the deserts still around 5 degrees above average.
For the weekend, high pressure aloft will bring a warming trend with the marine layer becoming shallower by Saturday night and Sunday. Saturday will be a few degrees warmer than Friday at lower elevations to around 5 degrees warmer for the mountains, then a few degrees warmer on Sunday for the lower deserts to 5 to 10 degrees warmer for the inland valleys.
With the warming, high temperatures on Sunday will be a few degrees above average near the coast to 10 to 15 degrees above average for the deserts, mountains, and inland valleys. High temperatures on Sunday for the lower deserts will be mostly in the 90s. NBM has a 64 percent chance on Sunday and again on Monday for Palm Springs to have a high temperature of 100 or higher.
(Monday through Thursday), A low pressure system over the eastern Pacific will eventually move inland through southern California and northern Baja some time around the middle of next week. Cooling will begin to spread inland on Monday with the cooling continuing through Thursday. With the cooling, high temperatures on Thursday will be around 10 to 15 degrees below average for the mountains and inland valleys.
There do remain model differences on the speed and timing of the inland movement of the low pressure system around the middle of next week. This will affect how quickly and when the marine layer will deepen sufficiently for night and morning coastal low clouds extend well inland and onto the lower coastal slopes of the mountains.
190930z, Coast/Valleys, Low clouds filling the coastal basin this morning. Bases 1800-2200 feet MSL with tops to 3200 feet. VIS restrictions where clouds and terrain intersect. Expect clearing to the coast 17-19Z, although some low clouds may persist at the beaches after 19Z. Low clouds to push ashore after 00Z and inland overnight, again filling the coastal basin early Saturday. Bases 2000-2500 feet MSL with VIS restrictions in foothills.
Otherwise, SCT cumulus at around 10000 feet over mountains between 19-02Z and SCT clouds at/above 20000 feet MSL with unrestricted VIS today and tonight.
No hazardous marine conditions are expected through Tuesday.
Ca, Wind Advisory from noon today to 3 AM PDT Saturday for San Gorgonio Pass Near Banning.
PZ, None.
