A cold storm slowly advanced toward the Southland Tuesday, with forecasters warning of windy, chilly and wet conditions that will persist well into the weekend.
National Weather Service forecasters called the system “a very complex storm event” that will bring “significant impacts” to the region, “some not experienced in decades.”
“A strong cold front will move over southwest California through Wednesday morning with very windy conditions and rapidly falling snow levels,” according to the NWS. “Cold, showery weather will persist until an unusual winter storm brings periods of heavy rain and heavy mountain snow to the region Friday through Saturday night.”
A winter storm warning will be in effect in the Los Angeles County mountains from 7 p.m. Tuesday through 4 p.m. Saturday, with forecasters anticipating snow levels dropping to 1,500 feet by Wednesday morning, and up to 5 inches of snow falling by Wednesday night, accompanied by winds gusting as high as 75 mph.
Forecasters said 2 to 5 feet of snow could accumulate by Saturday night in elevations over 4,000 feet, but some isolated areas could get as much as 7 feet. Accumulations of 6 to 12 inches are possible by Saturday night at elevations as low as 2,000 feet, with “significant snowfall” expected on “most major mountain passes.”
The Antelope Valley will be under a less severe winter weather advisory from 4 a.m. Wednesday to 4 a.m. Friday, with 3 to 6 inches of snow possible in foothills and 1 to 3 inches on the valley floor, all accompanied by winds of up to 65 mph.
Windy weather will be the primary early impact of the storm system, with forecasters predicting widespread gusts of 30 to 50 mph in many areas, while the mountains and Antelope Valley could get gusts from 55 to 75 mph.
“There will be the potential for tree damage and power outages just due to winds alone through Wednesday, along with travel impacts at our major airports,” according to the NWS. “Snow levels drop rapidly from the current 6,000 feet range to near 1,000 feet tomorrow (Wednesday).”
Several inches of snow could fall Wednesday on the Grapevine section of the Golden State (5) Freeway, forecasters said.
Scattered rain and snow showers are anticipated to continue Thursday, with the snow level hovering around 2,500 feet, forecasters said.
Temperatures in most valley and coastal areas will remain in the 50s into Friday.
Rain and snow are expected to get heavier Thursday night through early Saturday, with some areas seeing rainfall rates of a half-inch to 1 inch per hour, “bringing a threat of urban flooding and issues near recent burn areas,” according to the NWS.
Overall, Los Angeles County coasts and valleys could get a total of 2 to 4 inches of rain, with some foothill areas possibly receiving 4 to 6 inches.
“Low snow levels will mean that this could be the largest amount of 24-48 hour snowfall seen in decades for our Ventura and Los Angeles County mountains,” according to the NWS. “… Snowfall of this rate and amount could lead to damage to structures and trees with an immense threat of avalanches, especially in the eastern San Gabriel Mountains by Saturday.”