ITHACA, N.Y. -- If you go over the river or through the woods, or traverse Interstate 81, or venture the eastern railroad corridor, you may be curious to know your chances of a 'white' Thanksgiving, as provided by the Northeast Regional Climate Center at Cornell University. A chart gives the probability of one-inch or more of snow on the ground Thanksgiving morning. "This is not a forecast," said Keith Eggleston, climatologist at the center. "For example, Caribou, Maine, is listed as 53 percent. This means that on the average, every other year there will be at least an inch of snow on the ground on Nov. 27 (the day on which this year's Thanksgiving falls)."