A cold storm out of Canada headed for the Southland today, threatening snowfall and hazardous travel conditions in the Antelope Valley and at low elevations in the San Gabriel Mountains beginning Tuesday night, forecasters said.
Not much rain is expected as a result of the storm, said National Weather Service meteorologist Dave Bruno, adding that the lion’s share of the precipitation is expected in the San Gabriel Mountains and the Antelope Valley but only about a 10th of an inch of rain in other valley areas of Los Angeles County.
The snow level will fall to 2,000 feet or lower late Tuesday into Wednesday, likely causing between two and four inches of snow accumulation on the floor of the Antelope Valley and accumulation on Interstate 5 through The Grapevine, according to a National Weather Service statement. Rain is also expected.
The heaviest snow accumulation is expected over the north-facing slopes of the eastern San Gabriels and adjacent Antelope Valley foothills, mainly east of Highway 14 (the Antelope Valley Freeway), where up to a foot of snow is possible through Wednesday, the statement said.
The snow is expected to taper off Wednesday afternoon, but cold, dry conditions are expected on Thursday, New Year’s Day.
Forecasters said rain and snow will start coming down late Tuesday afternoon, accompanied by winds — 10 to 20 miles per hour with gusts of up to 40 mph, with the strongest winds expected in the L.A. County portion of the San Gabriels.
A winter storm watch, which points to dangerous mountain conditions, will be in effect in the Antelope Valley and the Los Angeles and Ventura county portions of the San Gabriels from Tuesday afternoon through Wednesday afternoon.
“The combination of snow and wind will lead to very hazardous conditions for anyone venturing into the mountains,” warned the NWS statement. “Roads will be icy and road closures are a strong possibility,” including Interstate 5 over The Grapevine and Highway 14 through the Los Angeles County mountains and Antelope Valley.
“Only travel in an emergency,” the statement said, urging motorists to pack emergency supplies if they must travel.
In the meantime, a cold mass will linger over much of Southern California this morning, and a frost advisory was to be in effect until 9 a.m. An even colder air mass will spread over the region between Wednesday and Thursday, according to the NWS.
Temperatures will fall to between 33 and 35 degrees Fahrenheit for two or more hours this morning, forecasters said.