Patchy FZDZ developed as the system pulled out overnight near Chi metro, created some slick spots. ORD had -FZDZSNGS at one point. After that, several hours of aircraft-induced snow showers that can still be seen on TORD, although fading. Bet some localized spot in NE Dupage saw something measurable out of it, as it actually came down at a good clip for a minute or two directly underneath any of the showers.