The West, the Plains, the South, the Midwest and the Northeast will be impacted.
More than 40 states from Washington to Massachusetts are set to be impacted by new winter storms on the move.
After up to 18 inches of snow pummeled California to Colorado this weekend, nine states in the West and the Plains are under blizzard warnings Monday. The storm will impact Washington, Oregon, Idaho, New Mexico, Colorado, Texas, Oklahoma, Kansas and Nebraska.
Monday night into Tuesday, that snow will move into Chicago, Milwaukee and Green Bay, Wisconsin.
Meanwhile, in the South, tornadoes and flash flooding are possible on Monday along the Gulf Coast, from Texas to Florida. New Orleans to Pensacola, Florida, are in the bull's-eye, but tornadoes are also possible in Houston.
Schools in Louisiana's St. James, St. Charles and Jefferson parishes will dismiss early on Monday due to the looming severe weather.
On Tuesday, the severe weather and tornado threat will be from Florida to the Carolinas, including Tallahassee, Jacksonville, Savannah, Charleston, and Charlotte.
In the Northeast, flooding is possible Tuesday from Virginia to Maine, especially along the Interstate 95 corridor from Washington, D.C., to Philadelphia to New Jersey to Connecticut and Massachusetts.
The threat for flooding from the quickly falling 3 inches of rain is further enhanced by the snow melt from this weekend's storm.