WASHINGTON -- Here's one thing some will not be so thankful for: a messy mix of snow, rain and sleet for Turkey Day.
A storm will dump rain and snow across the East Coast early Wednesday, causing delays of up to six hours on the busiest travel period of the year.
About 30 million people from the mountains of North Carolina to Maine could be affected.
"The storm will have a major impact nationwide to air travel, as the ripple effect from delays and cancellations in the Northeast hubs impacts the rest of the country," CNN senior meteorologist Dave Hennen said.
"Expect very long delays, in some cases averaging three to six hours for major airports in D.C., Philadelphia, New York and Boston, which will be impacted by a combination of heavy rain, snow and wind," Hennen said.
"Most delays and cancellations will occur from late morning through Wednesday evening."
The silver lining for Thursday morning fliers? "By Thanksgiving, the storm will be exiting, and conditions should return to normal," he said.
Rain and snow
Rain and snow will begin to hit the Washington, New York and Boston metro areas Wednesday morning.
Travelers can expect some significant snow accumulations.
Though Washington should see a mix of rain and snow, areas far west of the city will get heavy snowfall. Philadelphia will get about an inch of combined rain and snow.
Three or 4 inches of snow are possible in New York City, with heavier accumulation in northern New Jersey and in the Hudson Valley.
Boston can expect rain and snow in the morning, changing to all snow in the late afternoon and evening. The city is forecast to get 4 to 5 inches of snow, with 10 to 15 inches in central Massachusetts.
Mike Todd, a spokesman for the New Hampshire Department of Safety, said power outages are a major concern.
"This is New England, this is just another winter storm here, and the complication is just that it's the holiday weekend," he said. "We caution individuals to drive carefully and slowly. Consider staying put if you're concerned. Safety first, as always."
Pennsylvania said it'll have state police and the National Guard in the state emergency operations center. State officials urged residents to avoid the roads if they can.
"The bottom line is the less cars the better, the less traffic the better," said Cory Angell of the Pennsylvania Emergency Management Agency. "If you don't have to go, you don't need to go. You don't want to be stuck in a queue for hours and then run out of gas and what not. It's important people realize there are hazards involved with travel, and more often than not they don't."
So far, airlines have canceled at least 164 flights for Wednesday, and that number is expected to increase, according to FlightAware.com.
Fliers should check airline websites to see about rebooking flights.United Airlines, Delta Air Lines, American Airlines and other carriers are waiving rebooking charges for holiday travelers in the Northeast.
"Customers ticketed on American Airlines, American Eagle or US Airways or US Airways Express flights on November 26 to, from, or through (18 affected airports) may change flights without penalty, have the ticket-reissue charge waived for one ticket change, and begin travel as early as November 25 or as late as November 27 under American's current travel waiver," according to an airline release.
Midwest affected, too
The Northeast isn't the only region where bad weather is predicted. Light snow is forecast until Thursday in Minneapolis, Chicago and other parts of the Upper Midwest. The Northwest is expecting rain, with snow in the mountains. Denver is expecting wind gusts of up to 30 mph on Tuesday and 15 mph on Wednesday.
AAA is expecting 46 million Americans to travel 50 miles or morefrom home during the Thanksgiving weekend, and 90% of them are traveling by car. That would be the most travelers since 2007.
Drivers should check weather forecasts before setting out on the road, and travelers should also check tire pressure, car batteries and windshield wipers.
On the bright side, people traveling by car will probably pay less for gas than in recent years, AAA says.
The current average price of gasoline in the United States is $2.85 per gallon, 43 cents per gallon lower than the average price at the same time last year.