A winter storm is expected to impact Southwest California this weekend.

A broad upper level, low-pressure system will prevail across California this weekend, bringing widespread rain and mountain snow to the region.

Most of the precipitation will fall in a four-to-six hour period in advance of the cold front. The rain and cold is expected to move into Los Angeles County mid-morning Saturday and Saturday afternoon. Showers will likely affect the region Saturday night into Sunday, with brief heavy rain possible with the cold front.

Rainfall estimates with this storm are expected to generally range between three-quarters and one and a half inches in the foothills and mountains.

There is also the possibility of thunderstorms for all areas Saturday and Saturday night, with the thunderstorms producing brief heavy rain as well as small hail.

Snow levels are expected to range between 5,000 and 6,000 feet ahead of the front, then lower rapidly to around 3,000 feet Saturday night into Sunday. Snow accumulations of 10 to 16 inches will be possible at elevations above 6,000 feet, with lighter accumulations across the lower mountain elevations.

The low snow levels could impact major traffic corridors such as I-5 from the Grapevine into Castaic, Highways 14 and 138 through the Soledad Canyon and Antelope Valley and Highway 33 in the Ventura County mountains.

The Antelope Valley may see light snowfall with this event.

Wind gusts around 45 MPH are expected to impact the mountains and Antelope Valley at times through the weekend ,adding to the difficult winter weather driving conditions.

Due to the potential combination of snow and winds, a winter storm watch has been issued for the mountains of Ventura and Los Angeles Counties.

Once the colder air filters into the regions there will be a major concern for black ice on mountain roadways late Saturday into Sunday.

In addition, there will be the potential for small hail and ice pellets during this time, which could make highways slick in coastal and valley areas. Also, there is the potential for frost in colder wind-sheltered locations early Sunday morning and again Monday morning.

Anyone planning to travel into the mountains and deserts this weekend should be prepared for the possibility of winter weather driving conditions, which could be deadly for unprepared campers or hikers.