NEW YORK (CNN) -- When the 79th Macy's Thanksgiving Day Parade takes to the streets of New York City on Thursday, the balloons may need beefed-up security.No, there haven't been any threats against the Scooby Doo or SpongeBob SquarePants balloons, but forecasts of fierce wind, rain showers and snowstorms have police and city officials considering ways to avoid accidents involving the balloons.To the chagrin of children -- and some adults -- around the nation, that may mean grounding the popular attractions should the weather get too bad, Police Commissioner Ray Kelly said. Meteorologists and city officials will make that call as early as 6 o'clock Thanksgiving morning, three hours before the parade kicks off."If there are winds that are stronger than 23 mph or gusts that are over 34 mph, the balloons won't fly," Kelly said.If intense winds become a problem after the parade is already under way, police officers traveling with the balloons will decide whether to ground the helium-filled characters.Mike Giurici, a veteran parade pilot, said the emergency landing procedures are practiced three times a week. It typically takes about five minutes to ground a balloon, he said.Weather has bungled balloons in the past, most notably in 1997, when heavy winds sent The Cat in the Hat balloon plowing into a lamppost that toppled onto four people. One woman suffered permanent brain damage.Since then, Macy's has implemented improved training for the approximately 1,700 people who help handle and direct the massive balloons.The training, which is monitored by New York City police, includes watching videos and reading directions, said John Piper, vice president of Macy's Parade Studio.The training is mandatory for about 300 of Macy's "flight-team members," but only two-thirds of handlers have marched in previous parades or completed the field training in which they participate in handling simulations, Piper said.The parade's 32 balloons -- which include Big Bird, Humpty Dumpty and Chicken Little -- require between 40 and 60 handlers each, according to the Macy's parade Web site.The parade, which began in 1924, is expected to draw 2.5 million spectators and 44 million television viewers, according to the retailer.