Thursday afternoon
Colder air will start to slide into the area starting by mid afternoon and some of the rain will change over to light snow. Temperatures will be in the low 40s and then begin to drop rapidly through the afternoon and evening. We will probably be in the mid 30s in Chattanooga by afternoon drive.
There could be a dusting in the valleys, but some of the higher elevations will have up to an inch mainly on grassy surfaces. The best chance for more than an inch will be in the Blue Ridge mountains east of Chattanooga, that will include the mountains in East TN, NE GA and western NC. We could expect 1-3 inches out there.
Thursday night
Skies should be clear and it will be cold Friday morning with lows in the 20s. No major problems expected as most, if not all, of the rain will have dried up. Some patches of ice are always possible. Major roadways and secondary roadways should be fine for Friday morning.
Travel should not be a problem except for a few icy patches in some of the mountains. Those headed northeast to Bristol and points north could be a problem tomorrow night.