Kansas City International Airport, for example, has an 85% chance of snowfall exceeding .1 of an inch, according to data from the weather service. The probability of higher snowfall totals drops rapidly, with only a 50% chance of snowfall exceeding 1 inch. The chance of 2 inches or more of snow is less than 10%.

At least 46 million people were under a winter storm warning as of Thursday as the storm spreads along the Gulf Coast Friday, according to the weather service. The storm should weaken by Saturday, bringing lighter snow between 1 and 3 inches to parts of the Northeast, the Mid-Atlantic and the Ohio Valley before exiting off the Carolinas.

The National Weather Service has issued a Winter Storm Warning starting at noon Saturday and lasting through 3 a.m. Monday. A rare Blizzard Warning has also been issued for many c