Although it'll be mostly sunny on Monday, expect an Arctic blast when you head out the door. A dangerous deep freeze in the Philadelphia area is leading to slick sidewalks and roads. Chopper 3 was over Philly's skyline this morning and captured the bitterly cold conditions throughout the city. #arcticblast #philadelphia #philly #pawx #newjersey #jersey #southjersey #delaware #NEXTweatheralert #NEXTWeather