The West, Plains, South, Midwest and Northeast will be affected.
More than 40 states from Washington to Massachusetts are set to be affected by new winter storms on the move.
After up to 18 inches of snow hit California and Colorado this weekend, nine states in the West and Plains were under blizzard warnings Monday. The storm will affect Washington, Oregon, Idaho, New Mexico, Colorado, Texas, Oklahoma, Kansas and Nebraska.
Monday night into Tuesday, snow will move into Chicago, Milwaukee and Green Bay, Wisconsin.
Meanwhile, tornadoes and flash flooding are possible further south on Monday along the Gulf Coast, from Texas to Florida. New Orleans to Pensacola, Florida, are at the center of attention, but tornadoes are also possible in Houston.
A tornado watch has been issued for an area including Houston and Beaumont, Texas, and Lake Charles, Louisiana, until 9 p.m.
Schools in St. James, St. Charles and Jefferson parishes in Louisiana will close early Monday due to looming severe weather.
On Tuesday, the severe weather and hurricane threat will extend from Florida into the Carolinas, including Tallahassee, Jacksonville, Savannah, Charleston and Charlotte.
In the Northeast, flooding is possible Tuesday from Virginia to Maine, especially along Interstate 95 from Washington, D.C., to Philadelphia, to New Jersey, to Connecticut and Massachusetts.
The flood risk is enhanced by up to 3 inches of rain due to melting snow from this weekend's storm.
