A seemingly relentless series of severe storms, likely with deadly tornadoes, are forecast to rip across parts of America’s Midwest and South over the next couple of weeks, especially Friday, meteorologists said.

An unusual weather pattern has set in, last week triggering the devastating tornado that hit Rolling Fork, Miss., and meteorologists fear this Friday will be one of the worst days, with much more to come. The National Weather Service said 16.8 million people live in the highest risk zone, and more than 66 million people overall should be on alert Friday.

“It’s pretty darn clear that somebody is going to take it on the nose on Friday,” said Northern Illinois meteorology professor and tornado expert and chaser Victor Gensini.

“It’s just a matter of where and exactly when.”

The weather service is cautioning a large area of the country — including parts of Iowa, Missouri, Arkansas, Illinois, Indiana, Kentucky, Tennessee, Mississippi, Alabama, Louisiana, Alabama, Texas, Oklahoma, Ohio, Wisconsin, Minnesota, Michigan, West Virginia, Georgia and Kansas — to be alert for intense thunderstorms, tornadoes and other damaging winds. Big cities in the highest danger area include Memphis, St. Louis, Des Moines and Little Rock.