10:35 PM Tuesday: clear skies have allowed temps to fall faster than initially expected, particularly along/west of a WI Dells-Madison-Janesville line. Many locations have fallen to/below freezing over this part of the area. Slick spots are possible, particularly on elevated surfaces & where standing water remains from recent snow melt. Use caution if traveling late tonight over the northeast half of the area. Temps will gradually warm above freezing following 3 AM, ending slick spot potential.