With powerful wind gusts in the forecast, organizers of the Macy's Thanksgiving Day Parade expressed hope Wednesday that the weather will cooperate and allow the event's giant balloons to float through the corridors of Manhattan.

City officials said they would decide before the parade starts at 9 a.m. if conditions are safe for the balloons to fly. They will make their decision based on information from the National Weather Service, wind-measuring instruments along the route, and their own judgment.

"You don't want to ground the balloons and all of a sudden have the wind die," unnecessarily disappointing parade-goers, said Jarrod Bernstein, a spokesman for the New York City Office of Emergency Management.

Spectators stood in the light rain on Manhattan's Upper West Side Wednesday evening and cheered as the massive balloons were spread out flat on blue carpet and inflated, then covered in netting and held close to the ground.

Wind gusts could reach 35 mph Thursday, and rain and temperatures in the 40s were forecast. City guidelines call for the event's trademark balloons like Snoopy and Big Bird to be grounded if winds reach 23 mph and gusts exceed 34 mph.

Those rules were put in place after 45 mph winds sent a Cat in the Hat balloon careening into a metal pole during the 1997 parade, leaving a woman in a coma.

During last year's event, two sisters, ages 11 and 26, were hurt by debris when a giant M&M's balloon snagged a streetlight. A city report said the mishap was not caused by the weather, but rather discrepancies between parade guidelines and actual conditions along the route.

If the weather does not cooperate Thursday, parade organizers have some flexibility in flying the balloons. Some of the balloons could be tethered to vehicles and essentially act as floats. The parade will also have a handful of "balloonicles" — balloons powered by motorized vehicles — that are less susceptible to wind conditions because they are grounded.

And regardless of the weather, the parade will go on with dozens of floats, marching bands, clowns, performers and celebrities.

The parade will feature 33 floats with themes as varied as Charlotte's Web and Barbie, almost a dozen marching bands from across the country, and celebrities including Barry Manilow, Gloria Estefan and Ciara.

John Piper, who directs the Macy's studio where they make the balloons and floats, said he is most excited for people to see a hot-air balloon created for this year's event, inspired by "Around the World in 80 Days"

"I think it's going to be just amazing," said Piper, who has been a part of the event for 26 years.

About 600 children from Camp Broadway, for theater-loving children around the country, will perform the opening number of the parade. They will be clowning, singing, tapping, drumming and dancing their way through the city.

Ten-year-old Taylor Rosenberger from Orange County is performing as a clown with the group. "I'm excited," he said. "We actually get a float."

To protect against accidents, seven wind-measuring devices have been installed along the parade route to allow the city to monitor weather conditions in real time, Bernstein said. Police officers assigned to each balloon will be able to communicate changing conditions to the handlers, who will in turn adjust the flight pattern.

"We are able to check every location and it will allow us to adjust how high or low to fly the balloons," Bernstein said. "I'm extremely confident that we have done a lot of work to make this parade as safe as it possibly can be."

Organizers say the Macy's balloons were grounded only once in the parade's history — in 1973 because of severe weather conditions.