The Philadelphia region is preparing for a significant weather shift with snow squalls expected Friday night, followed by the season's coldest air. CBS News Philadelphia reports that the area will experience snow showers and squalls, potentially causing reduced visibility and dangerous travel. The incoming cold front will bring Arctic air, driving temperatures below zero over the weekend. This pattern continues the week's trend of frigid conditions, where temperatures have struggled to rise above freezing. Residents are advised to prepare for severe cold and potential snow accumulation.