Natalie DiBlasio

USA TODAY

As a record number of Americans prepare to hit the road for the holidays, a massive storm is poised to disrupt travel plans for two-thirds of the nation.

Starting Tuesday, the system — stretching from the Midwest down to the South and up the East Coast — will bring heavy rain, thunderstorms and strong winds that are likely to cause travel headaches on the roads and flight delays from the Great Lakes to the Mid-Atlantic and New England.

"We worry about any kind of weather when it comes to holiday travel," Weather Prediction Center meteorologist Brian Hurley said. "A lot of airports will be affected. It doesn't look like we will have significant snow but with the rain and wind, delays are imminent."

The heavy rain will begin in the South and Southeast on Tuesday hitting Atlanta, Charlotte, Nashville and Montgomery, Ala., before marching north to the Ohio Valley and the Great Lakes to batter Indianapolis, Cincinnati and Detroit. On Christmas Eve, the storm will gather strength, lashing areas from Tampa to eastern North Carolina up to D.C., Philadelphia and Boston.

"Especially on Christmas Eve, the rain is going to be heavy enough, and there is going to be wind, so I'd think there will be some delays and a slower go than usual on the interstates," AccuWeather senior meteorologist Dan Pydynowski said. "Certainly not the ideal travel day."

Those hoping the storm will bring them a white Christmas are likely out of luck, except in Wisconsin and northern Michigan, Hurley said. Temperatures in the Mid-Atlantic and Northeast will be on the warm side, meaning the massive storm will only bring rain.

Because of improvements in the economy and lower gas prices — down nearly 80 cents from the same period last year— AAA is expecting 98.6 million Americans to travel 50 miles or more for Christmas. That's a 4% increase over last year and the largest number in history.

Meanwhile, a smaller system will target the Pacific Northwest on Wednesday, bringing rain to Seattle and Portland. By Christmas Day, that storm could dump rain or snow in the central Rockies, Salt Lake City and Denver.