The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.
This is just an analysis of the synoptics that may affect Florence and how intertwined factors may make big differences in terms of a landfall vicinity if Florence impacts the Eastern Seaboard.
Based on this FSU run and the synoptics, timing, position of the LLC of Florence, and movement of Florence, as well as the synoptic factors of a possible positive NAO and EPO and the timing and intensity of the ridging/troughing will make big differences. Here's a graphic that goes into details on my thoughts on the synoptics and why timing will be everything...

The timing of the two ridging complexes merging, as well as Florence's possible more southerly track, as well as the intensity and movement/speed of Florence and the positive EPO/NAO synoptics, as well as the timing and intensity and speed of rate of the trough progged to approach the Eastern Seaboard, will all make big differences in regards to track and possible threatened areas if Florence impacts the Eastern Seaboard. On this visible loop, you can see clear evidence a further south (south-southwest) relocation of the broad circulation center (LLC) near 17N and 47W.
Based on the more southerly (south-southwest) relocation of the broad circulation center (LLC) of Florence, as the first ULT (upper-level trough) creating shearing over Florence pulls out, mid-level steering currents and the west-northwest movement of the relocated LLC may support a slightly more southerly track than indicated by the guidance.
Any thoughts? As for Herbert's Box, it has been proven to be unreliable, as synoptics vary. Andrew only clipped Herbert's Box, and the synoptics prove that you can't rely on magic theories for accurate synopsis.
This is not -removed-, either, nor is it a forecast. This is unofficial and just an analysis of the synoptics.