Cool and very windy this weekend with light rain/snow chances through Sunday. Warming trend next week before a large low may bring additional precipitation mid to late week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, Incoming Weather System To Bring A Windy Weekend,
A deepening low off the coast of California will begin to impact the region today as it pivots south, bringing cooler weather, ample clouds, and windy conditions. As the gradient tightens overhead today, strengthening westerly winds could gust as high as 30-40 mph this afternoon and evening, primarily in wind-prone regions such as mountain passes and the desert mountain slopes. Winds weaken a bit overnight post-peak heating, but remain elevated for the desert side of the mountains into Saturday morning. At the same time, the marine layer will be deepening and spreading inland as low and mid level moisture is pushed into the region by the low. By sunrise Saturday, clouds will have filtered efficiently into the coastal basin and inland valleys, possibly pushing up to the mountains. Light rain showers/drizzle may begin as early as midnight Saturday, with highest chances for light rain accumulations for the coastal basin. Rain totals expected to be 0.00-0.10" through Saturday morning.
Heights fall quickly after today as the system inches towards the CA Coast, with highs around 5-10 degrees below normal for Saturday and 8-15 degrees below normal Sunday. Clouds remain present for much of the day on Saturday, spreading into the deserts by the afternoon, with on and off light rain showers across much of the region. As the system pushes inland late Saturday night into early Sunday morning, a 500mb jet max will pass just south of the region >80kts, which will struggle to mix down due to the timing of the passage. Regardless, very strong westerly winds will develop late Saturday evening and persist into Sunday morning - 20-30 for inland areas and 40 to 55 mph with higher gusts through mountain passes and on the desert slopes of the mountains. Due to this, the Wind Advisory has been expanded to include the Coachella Valley and San Diego County Deserts, both of which are likely to see gusts above 40 mph late Saturday. Make sure to tie down loose items or bring them inside prior to these peak winds. Blowing dust will be possible throughout this period, especially in the deserts, which may reduce visibility at times. Winds weaken a bit after sunrise Sunday as the system sweeps across, but expect strong, gusty winds to prevail into Monday. Peak heating on Sunday may allow some of the stronger winds to mix down to create another round of gusts greater than 30-40 mph at times in the deserts and on the desert slopes.
Outside of the winds, ample moisture and light rain will move across the region early Sunday morning. The snow levels will be falling from 7000ft on Saturday to around 5500ft Sunday morning as the system sweeps through. This will allow for some snow or rain/snow mix for elevations above 6000ft, although little in the way of accumulations are expected. Elevations above 6500ft may see 1-2 inches of snow, while only a dusting is expected below this elevation. Lower elevations aren't expected to see much rainfall through this event given the main corridor of moisture moves southward into San Diego County Sunday morning. Rain totals below the snow level could see anywhere from 0.10-0.30" across Saturday and Sunday, with slightly more expected in SD County closer to 0.25- 0.50", locally higher in the mountains. Any and all precipitation should come to an end by late Monday morning as the system moves up into the Great Basin, with drier air filling in behind it.
Quieter weather expected next week as temperatures slowly warm under weak ridging setting up between a larger trough over the Central US and a deepening low off the coast of CA. This low could be our next chance for precipitation, with some models more aggressive with its approach mid-week, while others slow the system. At this point, moisture seems to be lacking a bit with this low, so timing will impact any rain chances greatly. We will be keeping a close eye on this system but will manage expectations for now.
241745z, Coast/Valleys, VFR conditions expected through this afternoon. Low clouds based 2000-3000 feet MSL to return to coastal areas 00-03Z with more uniform coverage and inland extent, eventually filling most of the coastal basin by 12z Saturday. Bases likely to rise above 3000 ft MSL sometime 12-18z Sat. For Saturday afternoon, SCT-BKN low clouds based 3000-5000 ft MSL along with isolated -SHRA.
Mountains/Deserts, Westerly winds strengthen after 23z with widespread gusts 25-35 kts, locally to 45 kts along desert slopes and through mountain passes. Moderate up/downdrafts expected in lee of mtns. Areas BLDU (3-5SM) along desert slopes and locally into deserts. Winds may weaken by 5-10 kts after 15z Sat, but are expected to strengthen further Saturday afternoon.
Otherwise, SCT high clouds today becoming BKN tonight onward.
No hazardous marine conditions are expected through Wednesday morning, though brisk westerly winds 15 to 20 kts are expected each afternoon and evening through Sunday.
Ca, Wind Advisory from 2 PM Saturday to 11 AM PDT Sunday for Apple and Lucerne Valleys-Coachella Valley-San Diego County Deserts-San Gorgonio Pass near Banning.
PZ, None.
