A flood watch remains in effect Thursday for parts of Southern California as the region experiences rainfall and flooding conditions.

The strongest wave of a powerful winter storm reached Southern California overnight, bringing flash flood warnings, dropping snow levels and a possible tornado.

A powerful storm dropping drenching rain on flood-prone Southern California is raising concern among forecasters that it could produce a dangerous, widespread outbreak of tornadoes, damaging winds and fires along with a blizzard as it crosses the entire United States in the coming days.