The same storm system driving severe weather elsewhere in the country this week is fueling one of the most widespread and potent rounds of rain in Southern California since the historic January fires.

The storm, which forecasters said could produce tornadoes, is expected to strengthen Friday and move towards the central US.

The same powerful storm that battered Southern California with heavy rain and brought blizzard conditions to the San Bernardino Mountains is putting millions on alert from coast to coast.

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.

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