Thunderstorms are expected to impact several regions across the country on Memorial Day weekend making it harder to travel in the air and on the ground.

The Southeast and Southern Plains are slated to see major rainfall over the next few days, which could cause flash flooding.

“A cold front will arrive on Memorial Day, accompanied by increasing storm chances. Morning strong storms will give way to strong and severe storms in the afternoon,” said a Saturday report from the National Weather Service in Fort Worth, Texas.

“Although there will be a threat for large hail, the main concern will be from damaging wind gusts,” they added.

Their tracker said heavier rainfall is also expected in St. Louis and the surrounding area until Monday while noting the possibility of hail in Birmingham.

However, flights on the West Coast are also seeing delays due to incoming weather patterns.

On Saturday, Denver International Airport halted all planes due to severe thunderstorms.