Reuters: The central United States braced for strong thunderstorms, heavy rain and possible tornadoes on Thursday from an unstable weather system that has already produced a twister and flooding in Missouri. "There is certainly the potential for some violent storms," said Jayson Gosselin, a meteorologist for the National Weather Service in St. Louis. Some homes were damaged and large trees uprooted in the St. Louis suburb of University City when an EF-1 tornado, packing winds of about 100 miles per hour,...