ABCNews.com(NEW YORK) — The storm system that dumped half a foot of snow in Minnesota and the Dakotas on Monday is moving east with 13 states already looking at winter storm warnings, advisories or flash flood watches on Tuesday.The storm system is strengthening in the Great Plains and spreading heavy snow from the Dakotas into Iowa and Minnesota on Tuesday morning.Further east, into the Ohio Valley, heavy rain is moving through.As the storm system moves east, spring-like severe storms will break out from Cleveland to Houston.The biggest threat with these storms will be damaging winds, hail and a few tornadoes through Ohio, Indiana, Kentucky, Tennessee and parts of Arkansas and Mississippi.To the north, a swath of heavy April snow will fall from Sioux City, Iowa, to Minneapolis and into Green Bay, Wisconsin, and Traverse City, Michigan, where some areas could see six to twelve inches of snow.By Wednesday, the storm system and cold front will approach the East Coast and stretch from Florida to Maine. Some of these storms could be strong to severe with damaging winds and hail. An isolated tornado is also possible.Bitter cold followsBitterly cold air, at least for April standards, will move into the Midwest on Tuesday night into Wednesday and reach the East Coast by Wednesday night.We are not done with the cold air yet. Another cold blast moves into the Midwest on Friday and spreads into the Northeast on Saturday morning. Copyright © 2018, ABC Radio. All rights reserved.