Arctic air surging south could glaze Colorado roads with ice in time for the evening commute Friday as Denver braces for a weekend of bitter, sub-zero cold. National Weather Service meteorologist David Barjenbruch said temperatures are expected to plunge twice Friday — first in the late morning and again in the late afternoon, when snow falling on warm roads has the potential to melt and then harden into an icy crust. RELATED: Everything you need to know about the polar vortex bringing extreme cold to Colorado “We’re used to driving on snow here in Colorado, but ice is a whole other thing,” he said. “It’s certainly a concern for the latter portion of the evening commute.” The cold air is being driven south from a polar vortex that is currently around Canada, Barjenbruch said. Related Articles Weather | Denver forecast to see more than 100 straight hours of below-freezing temps Weather | Denver weather: “Arctic” cold headed for city, windchill temps to hit 30 below zero Weather | Here’s how to prevent (and thaw) frozen pipes as arctic cold blast hits Colorado Weather | Here’s where to find shelter during metro Denver’s arctic cold snap Denver and other large Front Range cities will be under a Winter Weather Advisory from 4 p.m. Friday to 5 p.m. Saturday, reflecting road conditions. Between 3 and 7 inches of snow are expected to fall in some places overnight, and up to 10 inches could fall near the base of the foothills, including Boulder, according to the NWS. A week of mild weather in Denver will give way Friday to an overnight low of 9, with winds gusting up to 24 mph and 2 to 4 inches of snow possible. The winter cold will continue Saturday, with a high of 12 and a low of 4 degrees below zero forecast amid ongoing snow that will let up Sunday and return Sunday night. Barjenbruch said people working outdoors this weekend should plan on taking frequent warming breaks to avoid frostbite and hypothermia. “It’s going to be a rude awakening tomorrow — a full taste of winter, for sure,” he said.