By Brendan O’Brien CHICAGO (Reuters) – A massive winter storm walloped the central United States with heavy snow, freezing rain and gusty winds on Wednesday, threatening to make travel virtually impossible and possibly knocking out power for millions of Americans. Winter and ice storm warnings and watches were in effect for a wide swathe of the United States that reached from Texas and Colorado up through the Midwest and into Northern New York until Friday morning, the National Weather Service (NWS) said. Much of the northern part of the region could get 1 foot (30 cm) of snow while southern s…