A low-pressure system moving in from the north is expected to bring snow showers in the mountains and foothills of Los Angeles and Ventura counties along with the coldest temperatures in the region so far this winter season, forecasters said. The National Weather Service has issued a winter weather advisory beginning Sunday evening for snow, gusty winds and icy road conditions in mountain areas, including Interstate 5 near the Grapevine, Highway 14 through Soledad Canyon and Highway 33 above Ojai. The advisory will be in effect from 6 p.m. Sunday until 3 a.m. Tuesday.