The leading edge of a cold front is now moving into Los Angeles and Orange Counties this Wednesday afternoon... and will continue moving east southeast throughout the rest of Southern California tonight and Thursday morning.
The first area of the storm system (#1) is the warm core. This area is filled with strong south to southwest winds, and middle to high level moisture. What that means for us here in the desert is clouds will increase late this afternoon, and south to southwest winds will begin to increase rapidly in the mountain areas, as well as the desert slopes of the nearby high deserts, especially in the Pioneertown/Lucerne Valley area. An area of showers will move eastward, but is not expected to have much success making it over the mountains. Most low deserts will be dry or experience sporadic light showers, but the high deserts may see 0.10 - 0.20 inches of rain. Moderately strong winds may also get cranked up below the Banning Pass, into the I-10 corridor down toward Thermal by evening or early tonight. It's likely occasional south to southwest winds will also pick up in the extreme south areas like Indian Canyons and South Palm Desert. In between the south end and the I-10 corridor, it will likely fluctuate between calm and occasional erratic strong gusts as wind shifts and local effects of the mountains will play havoc with specific conditions.
As the second portion of the cold front moves through (area #2) late tonight, the temps will cool, and the winds will shift from SW to the WNW. The snow level will fall in the San Bernardino Mountains, and 2-6 inches of snow may fall there. Strongest winds will likely shift to areas along the I-10 corridor, as well as the high deserts from Joshua Tree east into the 29 Palms area. Clouds will lower and obscure the mountains at times. A few sprinkles or light rain showers may fall in the desert areas, but amounts are expected to be very light. Conditions should begin improving Thursday morning.
As of 2:30p Wednesday, the radar shows the leading area of rain moving into the urban areas of LA/OC.
Southwest winds are beginning to gust over 50 mph in some areas of the desert slopes east of Big Bear as of 2:30p (Gusts in red). At the moment, a weak SE up valley flow is over most of the Coachella Valley, with the onshore flow shift to the west only affecting the Whitewater area thus far. The area of WNW winds will likely begin to filter further southeast deeper into the Coachella Valley as the evening progresses. The hwy 62 corridor from Yucca to 29 Palms is beginning to get breezy SW winds as well.
Windy conditions and possible blowing dust should diminish Thursday afternoon.
Friday through Sunday should be fantastic, with temps in the high 70's - low 80's... eventually warming to the high 80's by next Tuesday.