Chances of severe weather are highest in western Iowa between 7 and 8 p.m. Monday evening and between 11 p.m. Monday night and 12 a.m. Tuesday in central Iowa. Eastern Iowa won't see storms until 1 a.m. Tuesday.

"Weather is always going to be fickle, and we aren't wanting to take that risk," Van Winkle said, adding that the last aircraft should be evacuated by about 1 p.m. ET. Other vehicles and aircraft equipment also will be moved into the hangars to prevent damage.

Following a week of heavy flooding which resulted in rescue crews pulling hundreds of people to safety, the Southeastern part of Texas is underwater. And more storms are expected to ravage other parts of the country, as the extreme weather outbreak rolls into its 6th week.