A cold upper-level low-pressure system brought the Southland heavy snow and gusty winds today, creating a possibility of highly hazardous whiteout conditions on some major roads in the San Gabriel Mountains and the Antelope Valley, forecasters said.
There also exists a slight chance of thunderstorms, according to the National Weather Service.
In the San Gabriel Mountains, a winter storm warning denoting severe winter weather conditions is scheduled to be in effect until noon Saturday.
The snow level will be between 4,000 and 5,000 feet in the San Gabriels, and snow accumulation of between six and 12 inches is expected, though it could be up to 15 inches along interior slopes, where the snow level will be down to 3,000 feet, according to an NWS advisory.
At the same time, the San Gabriels will be swept by northeast winds of between 25 and 35 miles per hour, gusting to up to 55 mph, especially over ridges and through passes and canyons.
"The combination of strong winds and snow will result in dangerous driving conditions due to blowing and drifting snow and near-zero visibilities at times," the advisory cautioned. "Portions of Angeles Crest Highway ... and surrounding roads will be most vulnerable to these conditions."
In the Antelope Valley a winter weather advisory heralding snow and blowing snow will be in force until noon Saturday while in the Ventura County portion of the San Gabriels, the advisory will expire at 4 this afternoon.
Between three and six inches of snow were expected in the Antelope Valley foothills above 3,000 feet, especially near Littlerock and Llano, according to NWS forecasters, who warned of northeast wins of between 15 and 25 mph, gusting to 40 mph.
Forecasters warned of the possibility of near-zero visibility at times on Pearblossom Highway (SR138) because of the combination of falling snow and high winds. Also threatened are Highway 33 and Lockwood Valley Road in Ventura County.
An urban-and-small-stream advisory that was in force in the mountain and the Antelope Valley Thursday night has been allowed to expire, forecasters said, but ponding in low-lying areas and some roadway flooding remained possible.
In areas where no snow was expected, a wind advisory will be in force until noon Saturday in the Santa Monica Mountains Recreational Area and the San Fernando and Santa Clarita valleys. Winds of between 25 and 35 mph gusting to 55 mph were expected in the Santa Monicas today -- a little weaker in the valleys, forecasters said.
In Orange County, a wind advisory is in effect until 10 p.m.
This morning, figures released by the NWS showed the strongest wind gusts were recorded in the San Gabriel Mountains, the Santa Clarita Valley and Malibu. The gusts included 67 mph at Camp Nine, 65 in the Malibu Hills, and 55 in the Newhall Pass.
The Los Angeles Department of Water and Power reported at about 9 a.m. that crews were working to restore service to about 1,000 customers in Pacific Palisades and about 850 customers in Pacoima. Several thousand Southern California Edison customers were without power on Thursday within the utility's 50,000-square-mile jurisdiction. Figures on current outages were not immediately available.
As was the case Thursday, temperature highs today will be mostly in the sixties. The NWS forecast highs of 36 on Mount Wilson; 53 in Lancaster; 54 in Palmdale; 58 in Saugus; 64 in Anaheim; 65 in Newport Beach, Pasadena, San Gabriel, Burbank and Woodland Hills; 66 at LAX; 67 in Long Beach; and 68 in downtown L.A.