A winter storm system is on the way to the Southland, with significant rain expected Monday and possibly as soon as tonight, along with snow in the mountains and high surf at the beaches.

The mountains and the San Fernando and Santa Clarita valleys could see some rain Sunday evening, according to the National Weather Service, but by Monday rain will fall over all of the Southland.

Up to an inch of rain is expected in the coast and valleys, while the foothills and mountains should see 1 to 2 inches, the NWS said.

Forecasters are also calling for a slight chance of thunderstorms Monday afternoon.

Around 6 inches of snow is expected by Monday in the mountains, with the snow level at about 5,000 feet. About 1 inch of snow is expected in the higher foothills of the Antelope Valley.

Temperatures will also drop precipitously Monday, with highs only reaching 57 degrees in downtown Los Angeles, the low to mid-50s in the San Fernando Valley and Orange County, and 49 in Lancaster.

A high surf advisory will be in effect at areas beaches until Wednesday morning.

The rain is expected to clear out by Tuesday, but temperatures will remain on the lower side. A cold weather alert is in effect through Wednesday for Lancaster, through Tuesday for Mount Wilson, and Tuesday and Wednesday for the Santa Clarita Valley. Near-freezing or freezing temperatures are expected overnight in those areas.