Jan. 31, 2011 -- An enormous storm packing a punch forecasters say hasn't been seen in years, is slowly making its way to the middle of the country where it is expected to unleash a potentially devastating mix of sleet, snow, ice and wind.

More than 18 inches of snow is predicted for many cities and the National Weather Service warns of 60 mph winds in open areas, up to 10-foot snow drifts and up to an inch of freezing rain. The NWS has issued a blizzard watch for southern Wisconsin, northern Illinois and northwest Indiana for Tuesday and Wednesday.

The storm will also bring dangerously low temperatures to the region. Wind chills of 40 degrees below zero are possible for parts of North Dakota, South Dakota and other sections of the Midwest. Southern states could be affected too; tornadoes and thunderstorms are possible as a result of the storm.

Chicago is currently forecast to receive 18 inches of snow. The record is 23 inches, set in 1967, which was almost eclipsed in 1999 when the city received 21.6 inches of snow. According to records dating to 1886 the city gets a storm of more than 10 inches about every three years, but only gets a 15 inch snow about once every 19 years.

The Windy City's two primary airports, O'Hare and Midway, typically handle about 2,800 flights daily. Airlines are encouraging travelers to rebook before the storm hits. O'Hare airport has 1,000 cots ready for travelers who get stranded. Meanwhile, transportation officials from Kansas City to Detroit readied storm-fighting equipment in preparation for weather that could cripple air travel in those cities as well.

In St. Louis and across Missouri, forecasters are predicting a possibly destructive and deadly mix for Tuesday: up to an inch of ice, followed by 3-to-4 inches of sleet, then perhaps a half-foot of snow or more.

This morning, customers began lining up at 7 a.m. waiting for Edele and Mertz Hardware in St. Louis to open. Steve Edele said snow shovels, ice melt and salt were the big sellers.

Ice Is the Big Worry

"'Freaking out' is a great way of putting it," Edele said. "The icing -- that's what scares people."

Ameren, a St. Louis-based utility company, opened its emergency operations center, out of concern that the snow and ice could bring down power lines. The company has six 53-foot storm trailers stocked with wire, poles and hardware ready to be dispatched to repair lines and other facilities.

While the Northeast has had record-setting snowfall already this winter, this will be the Midwest's first real taste of winter. The Federal Emergency Management Agency said that as the storm continues to move east over the next few days it could impact a total of 100 million Americans.

"A storm of this size and scope needs to be taken seriously," said FEMA Administrator Craig Fugate. "As we continue to do our part to watch the storm and work closely with our state and local partners as they get ready, it's critical that the public does its part to get ready. Already this winter we've seen how snow and ice can knock out power and affect transportation. If you haven't already, take steps now to get your homes and families ready, and be sure to check on your neighbors, especially the elderly and young children - those who can be most vulnerable during emergencies."

The Associated Press contributed to this report.