The NWS described the storm as "a confirmed large and extremely unsafe tornado".
Violent storms just north of Indianapolis completely destroyed a Starbucks and ripped roofs off of houses in what the National Weather Service is calling a "particularly unsafe situation".
Authorities say thousands of homes and businesses are without power in central in after at least two tornadoes moved through the region.
More than 22,000 customers were without power north of Indianapolis, Duke Energy reported on its website.
He says the complex has 16 buildings, and "probably eight of them don't have a roof". "We have not had any injury or fatality reports yet".
He estimated 20 to 30 cars had been damaged by falling tree limbs and air conditioners.
Local emergency dispatchers said only minor injuries had been reported. But he says the storm has cut power to about 12,000 homes and businesses in Howard County.
Law enforcement also confirmed a sighting of the same tornado reported east-northeast of downtown Indianapolis on Interstate 70.
Marion, Hamilton, Boone, Hancock and other surrounding counties were under a tornado warning late Wednesday afternoon, spurring schools to keep students inside after dismissal and Butler University to advise students to take cover rather than go to classes.
Tornado Warnings remain in place in parts of in, along with severe thunderstorm warnings and a flood advisory in parts of Indiana.
The National Weather Service forecast severe thunderstorms and heavy rain on Wednesday across portions of the central plains and mid-Mississippi Valley. He says there are reports of damage but he had no specifics.