The severe weather that killed 32 people across the South and Midwest over the weekend has faded, but another round of thunderstorms hit the same area on Tuesday.
Federal forecasters said wind, lightning, hail and rain, along with the possibility of a fast-moving, strong and long-track tornado, will hit the eastern third of the country Tuesday afternoon and overnight Wednesday.
The most severe storms can occur after dark, making tornadoes twice as dangerous as daytime twisters.
Severe storms are expected Tuesday and overnight across a large area stretching from the Great Lakes south to North Texas. Storms will begin earlier in Iowa and Illinois, but after midnight in parts of Oklahoma and Arkansas.
In the southern part of the danger zone, most storms occur at night. Large hail and wind gusts of 75 mph are possible.
A hurricane as strong as an EF-2, with sustained winds of 111 mph, has an added chance of blowing up cold air from the north and warm, relatively moist air from the Gulf of Mexico, forecasters said.
If strong winds change direction, dive and replace supercells, mesocyclones form vertical, thunderstorms and swirling storms, the system creates fertile conditions for hurricanes, they said.
Chicago, Detroit, Indianapolis and Toledo, Ohio are the cities most at risk for a strong hurricane.
“If they form,” National Weather Service meteorologist Melissa Byrd said of the thunderstorms, “they have the potential for very large and strong tornadoes.”
According to NBC News’ weather division, 42 million people were at risk of severe storms Tuesday. As the storm system stretches from northern Michigan to northern Louisiana, about 62 million people will be affected by Wednesday.
The National Weather Service says severe weather will develop along a vertical line from Des Moines, Iowa, to Little Rock, Arkansas.
Springfield, Missouri, joins Cedar Rapids, Iowa, Davenport, Waterloo and Iowa City as targets for the worst of the front, which the weather service described as having a moderate risk of severe thunderstorms.
“Strong tornadoes and particularly damaging winds are expected,” the weather service said in an outlook statement on Monday. “There will be a chance of severe overnight tornadoes in various areas throughout the afternoon and overnight.”
The largest city closest to the most extreme weather predicted is St. Louis, where thunderstorms and even some tornado activity are not uncommon in May. But this time the area is being cleaned up.
“We could see two rounds of severe weather in the afternoon and into tomorrow night,” said Byrd, who is based at the weather service office in nearby St. Charles.
In Wyoming, the Dakotas and Minnesota, north and west of those thunderstorms, the same front will produce blizzard conditions and record amounts of snow — up to 2 feet in places — are possible for April, the weather service said. and the NBC News Weather Division.
Experts say the U.S. and Southern Hemisphere are experiencing bad weather, with the cold fronts of Canadian and Pacific storms moving south and east and colliding with tropical air from the Gulf of Mexico.
But climate change will make extremes worse, resulting in colder cold fronts, stronger hurricanes and larger hail in the spring, and longer, hot streaks in the summer, they said.
In mid-March, the National Atmospheric and Oceanic Administration’s spring outlook called for moderate to major flooding from Minneapolis to St. Louis, despite continued drought in the northern and central Plains.
“Climate change is driving both wetter and drier extremes,” NOAA Administrator Rick Spinrad said in the outlook.