Maybe i am wrong but the 18z model runs have came out ALL to the west way more yet the NHC has it at 998 MLB 60mph and the same exact track no shift at all in the track.

5PM EVERY MODEL run i have seen at 18z is west of the current NHC track i hope they give reason in there disc cause i thought for sure they would move it more west but 998 MLB and 60mph winds moving NW AT 20

Now weather underground has the track shifted with the Florida west coast on the edge of the cone

at least in there discussion they made this clear...

Based on this expectation...
the forecast track shows Isaac moving northwestward for 12 hr or
so...followed by a turn toward the west-northwest. It is possible
the storm could make a sharper turn than forecast...as the UKMET is
showing an almost due west motion between the Florida Keys and Cuba
near the 36 hr point. The early part of the forecast track is
shifted a little to the left of the previous forecast...but still
lies to the right of the consensus models and the bulk of the
dynamical models.

So they are saying they are to the right of all the models which is good cause it keeps them in the clear if it nudges right along the west coast.