I hope this graphic makes sense because I just spent 20 minutes making it! :) It shows why I encountered freezing rain and not snow at 31 degrees on my way home from work:
In order to get snow, the air has to be at or below freezing throughout most of the column of the atmosphere.
With that said, we may see some slick spots. I still think that some people may see the entire column go 32 or below, so I'm not completely ruling out some light snow in spots.
Be careful if you are driving late tonight!