There's no chance the weather will affect ATL on Thursday. It's not supposed to hit ATL until mid-late afternoon on Friday. The real issue will be the 5p and later bank on Friday if they are short crews, and Saturday AM if the roads remain bad and/or if something happens to MARTA.

Re the get planes out, etc. Don't overthink things... if anything, they're going to be crew and staff limited... but a plane in TPA will still fly into ATL because it has a crew that can be used on another flight.