LOS ANGELES—After a cold and wet Christmas, the Southland is in for more of the same this week, with rain and snow in the forecast through New Year’s Eve save for brief respites on Dec. 26 and 27. Sunday’s high temperatures were mostly in the 50s, and in the upper 40s in the mountains. Overnight lows will drop into and 30s in some valley and mountains areas, and the high 20s in the Antelope Valley. Similarly cold temperatures were in store all week. A winter storm warning was issued from 4 p.m. Saturday to 10 a.m. Sunday for the Los Angeles County mountains—excluding the Santa Monica Range—where the snow level was expected to get as low as 3,500 feet, and 6 to 12 inches of snow were expected above 5,000 feet. That warning was set to transition to a winter storm watch from late Sunday night to late Monday night, …