Clear skies Monday night, along with diminishing winds will set up what will likely be the coldest morning of the winter across parts of the metro area. Temps around sunrise Tuesday are expected to hover near -10 over the deeper, fresh snow covering Chicago’s north and northwest suburbs. Readings in the city and south suburbs are forecast to range from zero to -5. The cold is expected to moderate somewhat midweek before polar high pressure builds across the Great Lakes bringing a second surge of very cold air. Arctic air masses are typically associated with clear, very dry conditions since the dense, cold air promotes high pressure. Barometers across the region are likely to register some of the highest readings of the winter heading into the weekend, likely topping 30.7”. As the core of high pressure shifts east on Saturday, south-southwest winds are to lock in, bringing the onset of a much milder regime that is likely to extend through early February.