In my opinion we have this incredible model variation because of the proximity of the two high pressure areas trapping the hurricane from steering forces that almost always what these models build off of in their predictions. Until the resolution of the conjoined highs this sucker is going to break dance in south GA giving everything from central FL to the NC line storm band training floods.
As Debby devolves into a pokey-cane, there will be adequate time to anticipate additional preparations. Unfortunately, Debby’s reach is vast. Thus, preparations will likely occur in the rain.
The other half of the equation is the Fujiwara "flirtation" late Tues-early Wed with the descending baggy trough out of the Great Lakes. This is why some models push it out into the Atlantic but then pull it back onshore in a really ugly 72-hour rain bamb centered on Charleston, SC. Shades of Harvey's doom loop in Houston.