D.C. area forecast: Icebox today, coldest since 1996; then gradual moderation to a warmer weekend

** Wind chill advisory immediate area through 6 p.m. | Wind chill advisory for N. Fauquier, Loudoun, and Frederick counties through midnight **

** Related info: Closings and delays | Staying safe in the cold | How the cold may rank locally | Polar vortex and climate change | Live blog on cold **