Forecasters say there's a possibility of severe weather across the U.S. from California to New England on Monday.
More strong thunderstorms along with possible tornadoes are predicted across the mid-Mississippi Valley.
Over the weekend, the most powerful twister to hit St. Louis in 40 years damaged thousands of buildings. The tornado destroyed up to 100 homes, shattered hundreds of panes of glass at the main terminal and blew a shuttle bus on top of a roof. Still, no one was killed or even seriously hurt.
Although the city's Lambert Airport reopened less than 24 hours later, dozens of flights have been canceled. The airport's Concourse C is still closed and complete repairs could take up to two months.
The tornado peaked at an EF-4 level, second-highest on the Enhanced Fujita scale, packing winds of up to 200 mph, National Weather Service meteorologist Wes Browning said. It was the most powerful twister in metropolitan St. Louis since 1967 - and eerily, it followed a path similar to that of the earlier tornado.
Entire subdivisions were destroyed. Cars were tossed about like toys, roofs tossed hundreds of yards, and 100-year-old trees sucked out by the roots.
Authorities said the twister did not claim any lives. They credited early warnings and common sense. But on Easter Sunday, many of those cleaning up the mess also thanked a higher power.
"I don't know why God decided to spare our lives, but I'm thankful for it," Joni Bellinger, children's minister at hard-hit Ferguson Christian Church, said Sunday.
For many Missouri churches, the storm coincided with Good Friday services.
"Just a big roar came up and I heard the big steeple fall. The doors right here blew right open," said one church member.
One Catholic Church sustained minor damage.
Worshippers from the Ferguson Christian Church had to hold Easter services at a local college after the storm severely damaged their sanctuary.
"We are convinced that our faith is not shaken, that our faith stands firm in God. Our building was shaken, but the church itself wasn't shaken. Our determination is to rebuild," said Stacy Garner, the church's pastor.
County officials said during a news conference Sunday that 2,700 buildings were damaged. Gov. Jay Nixon said Saturday that up to 100 were uninhabitable. The governor also credited early warnings with saving lives.
"The bottom line is the 34-minute warning and the heeding of that warning by the citizens has saved countless lives," Nixon said.
"The public did what we told them to do," the meteorologist said. "Many came out of the basement without a scratch, and there was nothing left" of their homes.