Strong winds, heavy rain and mountain snow are in Tuesday's forecast for much of the Western United States, and on Wednesday the storm will push into the central part of the country, where more than 4 million people are under winter weather alerts. Live: Track the storms yourselfFolks traveling through the Plains and Midwest after enjoying Christmas dinner and gift exchanges with family and friends will need to be extra cautious as roads throughout the region will remain hazardous into Friday. Making the roads more treacherous, snowfall is expected to reach 8 to 12 inches in those regions, with parts of eastern Colorado, western Nebraska and the Dakotas possibly seeing more than a foot of the white stuff. In the South, about 12 million will be under a slight risk for severe storms Wednesday, possibly bringing strong winds, large hail and isolated tornadoes in the afternoon and evening. Much of the South will see 2 to 4 inches of rain, possibly more in some areas, which could spur the threat of flooding through Friday. According to a report this month from the American Automobile Association, 112.5 million Americans are expected to be traveling during the holidays — a record and a 4.4% increase over last year.Of those, about 102.1 million will be driving. Another 6.7 million will fly. The rest will take trains, buses or boats, AAA says.