Another round of thunderstorms was aiming Tuesday for nearly the same area impacted over the weekend by severe weather that killed 32 people from the South to the Midwest.

Severe storms are expected Tuesday and into the night across a large area stretching from the Great Lakes all the way down south to the Gulf Coast, the National Weather Service said.

“Weather conditions in these areas could be life-threatening at times,” it said in a forecast discussion Tuesday.

The storms will start earlier in the day in Iowa and Illinois, but not until around after midnight across portions of Oklahoma and Arkansas.

For the southern half of the risk area, the majority of the storms will happen at night. Large hail and winds in excess of 75 mph are all possible.

There’s the added possibility that tornadoes as strong as EF2, with sustained winds of 111 mph, could form as cold air from the north and warm, relatively wet air from the Gulf of Mexico clash explosively, forecasters said.

Big cities most at risk for strong tornadoes include Chicago, Detroit, Indianapolis and Toledo, Ohio.

Chicago was under a severe thunderstorm warning as a massive front produced strong winds and large hail. It expired Tuesday afternoon, but could return in the evening, the weather service said.

The Chicago Fire Department said it responded to at least three reports of roof damage. No injuries were reported, but trees were felled and power poles were also damaged, it said.

At Chicago O’Hare International Airport, there were 77 cancellations and 341 delays for departing flights, flight tracking site FlightAware reported early Tuesday evening.

In western Illinois, a 90 mph gust was recorded in Moline, about 165 miles west of Chicago.

The presence of severe thunderstorm activity doesn’t bode well for the likelihood of tornadoes.

“If they do form,” National Weather Service meteorologist Melissa Byrd said of thunderstorms, “they have the potential for very large-scale and strong tornadoes.”

An estimated 42 million are under the risk for severe storms Tuesday, according to NBC News’ weather unit. That changes to around 62 million people on Wednesday, as the storm system stretches from northern Michigan to northern Louisiana.

The weather service’s forecast map for Wednesday’s most intense weather has shifted eastward and broadened since Monday. It now encompasses an area east of Dallas and extends northeast along a diagonal swath parallel to the Appalachian Mountains. It reaches Chicago and even parts of New York state.

Cities most likely to get severe weather Wednesday include Chicago; Detroit; Indianapolis, Indiana; Columbus, Ohio; and Memphis, Tennessee, according to the weather service.

“Potential storm hazards include strong tornadoes, damaging winds, large hail, and locally heavy rainfall and flooding,” the weather service said in an outlook report Tuesday.

St. Louis was among a group of cities — also including Milwaukee, Pittsburgh, and the New York cities of Buffalo and Rochester — with a slight risk of extreme weather Wednesday, the weather service reported. It may face a double wave starting Tuesday.

“We can see possibly two rounds of severe weather — in the afternoon and through tomorrow night,” said Byrd, based at the weather service office in nearby St. Charles.

Late Tuesday afternoon, the office said a tornado watch had been issued for parts of northern Missouri, western Illinois, and eastern Iowa. Severe thunderstorm warnings were in effect for the same region of Missouri.

North and west of that thunderstorm activity, in Wyoming, the Dakotas and Minnesota, the same front was expected to produce blizzard conditions and the possibility of record amounts of snow — as much as 2 feet in places — for April, according to the weather service and the NBC News weather unit.

Many of South Dakota’s state employees worked from home Tuesday under an order from Gov. Kristi Noem, who said the front’s snow and wind would make traveling to workplaces difficult and dangerous. Some highways were being shut down at nightfall as a precaution.

“Citizens should be prepared to stay home if possible,” Noem said in a statement.

Experts say the continental U.S. and the South in particular have the weather misfortune of being where cold fronts from Canada and Pacific storms move south and east and clash with tropical air from the Gulf of Mexico, creating an annual cauldron of stormy weather.

But climate change could be making the extremes worse, resulting in colder cold fronts, stronger tornadoes and bigger hailstones in spring, as well as longer, hotter streaks in summer, they have said.

In mid-March, the National Oceanic and Atmospheric Administration’s spring outlook called for moderate to major flooding from Minneapolis to St. Louis even as drought continued in the northern and central Plains.

“Climate change is driving both wet and dry extremes,” NOAA Administrator Rick Spinrad said in the outlook.