( CNN ) 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 . Use CNN 's winter weather tracker . 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 do n't have to go , you do n't need to go . You do n'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 do n't . '' 10 ways to survive holiday travel . 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 . The Northeast is n'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 more from 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 .
Airlines waive rebooking charges for travelers . Comment: East Coast travelers can expect some significant snow accumulations .