Both the 00Z operational ECMWF and the 00Z EPS ensemble mean have trended toward a stronger PV streamer (TUTT) over the western MDR by day six (120 hours). Given that Florence is likely to be weaker in the short term than originally forecast, the interaction with the TUTT may be sufficient to destroy the circulation and thus reduce any threat to the U.S. So strong vertical wind shear may be the factor that could prevent a (strong) TC landfall on the U.S. East Coast, given the otherwise favourable steering pattern that is present and expected to persist. There is a lot of volatility on recent EC/EPS runs in regard to the positioning and amplitude of large-scale features in the medium to long range, so any forecast at this stage is likely to be rather premature, highly mutable, and subject to large errors, so it should be labeled "low confidence."
Note that a large number of 00Z EPS ensemble members actually kill Florence by days six or seven (144 hours), due to the very TUTT that I have mentioned: