Severe thunderstorms were possible across a 1,300-mile area across the country's midsection, according to The Weather Channel. The affected area stretched from Minnesota and Wisconsin, through parts of South Dakota, Nebraska, Iowa, Kansas, Missouri, Oklahoma and down into most of Texas.
"The biggest tornado threat today will come in largely rural areas and low population centers," Weather Channel senior meteorologist Kevin Roth told NBC News early Monday. He said if twisters came they would like emerge in parts of Texas and Kansas — the other areas would like see hail and high winds.
The NWS issued a severe weather statement for parts of Oklahoma, warning of golf-ball-sized hail and winds of up to 60 mph.
"People and animals outdoors will be injured. Expect hail damage to roofs, siding, windows and vehicles ... and trees," the NWS said, adding "for your protection, move to an interior room on the lowest floor of a building."
On Tuesday, the severe-threat area was set to focus on northern Texas, Oklahoma, Kansas, and parts of Nebraska, Iowa and Missouri, before expanding slightly into Illinois on Wednesday.
"It's a large area but it's a stalled front that's not going to move much," Roth added. "It's going to be a repeated threat this week, possibly into Thursday and even into Friday."