The heavy storm bearing down on the Southland is expected to arrive in force Thursday, bringing what forecasters are calling an "atmospheric river" of moisture that will persist into Friday.
Rain, snow and strong winds could cause dangerous driving conditions through the Grapevine.
Storm timeline: Here's when heavy rain will hit Southern California
Winds in mountain areas will blow at 20 to 30 mph, with gusts ranging up to 50 mph. A wind advisory will be in effect for Los Angeles County mountains until 3 p.m. Thursday. Forecasters said the strongest winds are likely in the San Gabriel Peaks and the Grapevine area, making "driving difficult, especially for high-profile vehicles.''
The California Highway Patrol warned the freeway could be closed off and on for the next few days.
"The next couple of days, just pay attention to the weather reports and be patient and come up with an alternate plan," said CHP Sgt. KJ Pack.
While the lanes remain open, Caltrans is warning drivers to distance themselves from other vehicles due to slick roads.
A winter storm watch is in effect until Friday at 3 p.m. as this system may bring 2-4 inches of rain to some communities and more than 10 inches of snow to the mountains.
SoCal weather: Heavy storm drenching region Thursday, Friday