Record cold temperatures are blasting the Midwest and Eastern United States again today as a so-called polar vortex has descended as far south as Texas and Florida. In Chicago, it was negative 16 degrees Fahrenheit Monday, or as low as negative 42 with the wind chill. In northern Minnesota, it was negative 40 degrees Fahrenheit — that is the actual air temperature, not the wind chill. Here in New York, the temperatures plunged roughly 50 degrees in a matter of hours.