I think the 18z GFS is under estimating somethings for the CAD areas over northern Georgia and upstate SC. A wedge builds later on (1036/1034 high over the NE) so areas over northern Georgia/Upstate SC could see a cold rain to sleet/ZR to all snow (or a mix, depending on temp. profiles.) You have to factor in wet bulb temps. You also have to consider, with northeasterly winds coming from that wedge, and those winds blowing down the cold air surrounding the snowfall from NC, I think it could be colder than what the GFS is projecting for northern Georgia/Upstate SC. For AL/MS, rain could change to snow when the low makes it's way east of there. It's strange to me that there's no colder air making it directly behind the system further west. Typically, colder air rushes in behind winter systems. Of course, if things shift south, there would be more widespread snow over the southeast.