CHICAGO -- A wall of storms packing ice, sleet and rain could upend holiday travel plans as millions of Americans take to the roads, skies and rails Wednesday for Thanksgiving.
So far, the deadly storms barreling into the mid-Atlantic and Northeast haven't resulted in many flight delays or cancellations, but forecasters are expecting the weather to worsen throughout the day.
"The timing of the storm couldn't be worse," said Chris Vaccaro, spokesman for the National Weather Service headquarters in Silver Spring, Maryland. "We are seeing numerous threats as the storm is beginning to develop and intensify."
Heavy rain and breezy conditions were to strike the East Coast from the Carolinas to the Northeast on Wednesday, with ice and snow a possibility in the Appalachians, western Pennsylvania and western New York. Snow totals from the Ohio Valley to the interior of the Northeast were expected to be less than 10 inches), the weather service said.
The storm system, which developed in the West, has been blamed for at least 11 deaths, half of them in Texas. It limped across Arkansas with a smattering of snow, sleet and freezing rain that didn't meet expectations.
But even a weaker than expected storm system is potentially bad news the day before Thanksgiving - the anticipated busiest travel day of the year.
More than 43 million people are to travel over the long holiday weekend, according to AAA. The overwhelming majority - about 39 million people - will be on the roads. But more than 3 million people are expected to filter through airports, and the weather could snarl takeoffs and landings at some of the busiest hubs on the East Coast, including New York, Washington, D.C., Philadelphia, Boston and Charlotte, N.C.
Transportation officials advised travelers to check with their airlines and reduce speed on highways. Travel experts suggested airline passengers might be able to have penalty fees waived if they wanted to change their bookings because of the weather.
Weather woes aside, there were some things for travelers to be happy about this year. The Federal Aviation Administration last month lifted restrictions on the use of most personal electronic devices during takeoffs and landings, and some airlines, including American, have already begun allowing passengers to stay powered up from gate to gate.
On the ground, gas prices are a little cheaper than a year earlier. For car-less urbanites, the national passenger train service, Amtrak, is adding more trains for the holiday, and a new breed of express intercity bus was drawing more passengers hoping to escape airport hassles without sacrificing comfort.
The storm was threatening to ground giant balloon versions of Snoopy and SpongeBob SquarePants in the annual Macy's Thanksgiving Day Parade.
The iconic characters that soar between the Manhattan skyscrapers every year may not lift off Thursday if sustained winds exceed 23 mph and gusts exceed 34 mph, according to city rules enacted after fierce winds in 1997 caused a Cat in the Hat balloon to topple a light pole and seriously injure a woman spectator.
Current forecasts call for sustained winds of 20 mph and gusts of 36 mph.
"At this time, it is too early to make any determinations on the flight of the giant balloons," said Macy's spokesman Orlando Veras. "On Thanksgiving morning, Macy's works closely with the NYPD, who, based on real time weather data and the official regulations, determine if the balloons will fly and at what heights."
Balloons have only been grounded once in the parade's 87-year history, when bad weather kept them from flying in 1971. They're set to be inflated in Manhattan on Wednesday evening.
The parade was awash in animal-related protests over its floats, with controversies involving the unlikely pairing of rocker Joan Jett and Shamu the killer whale.
Activists planned to line the parade route to protest a SeaWorld float over accusations in a new documentary that the theme parks treat whales badly. And ranchers succeeded in getting Jett pulled off the South Dakota tourism float after they questioned why the vegetarian and animal-rights ally was representing their beef-loving state.
SeaWorld says the accusations have "absolutely no basis" and that "the men and women who care for these animals at SeaWorld are dedicated in every respect to their health and well-being."
Macy's said the parade doesn't engage in social commentary or political debate.