As near temperatures climbed to near records in parts of the central United States, a potent storm system was setting up to wallop the nation later.

Over the next week, tens of millions of Americans will be at risk of severe weather as a colossal storm marches across the country, threatening hurricane-force winds, major flooding, blizzard conditions and a possible tornado outbreak.

A potent storm system is expected to pour heavy rain on western states later this week before rumbling into the central United States, where it could spawn tornadoes