Another polar vortex is set to bring the mercury way down again in the area. Just the term “polar vortex” sounds like something out of a summer blockbuster, right? Tom Cruise, Will Smith, Katniss Everdeen, save us! Arm yourself with knowledge provided by the National Weather Service website. The NWS Windchill Temperature (WCT) index includes a wind child calculator and it provides links to practical information to help you plan for extremely cold weather.