Originally, I would have assumed that an adequate trough might cause a Caribbean tracker to bend north and threaten the Fla. West Coast or points north. Well, after taking a long look I for one am thinking that the GFS is going way overboard on its future development of essentially a large cutoff mid level low spinning off New England and causing a resultant weakening of the tropical ridge.
Per this mornings GFS 500mb, at 60 hour there are two stout 594 highs, one in the W. Gulf and one NE of Puerto Rico. A weakness along the US Eastern seaboard does exist, but these two anticyclones seems to be fairly well bridged. The large North Atlantic low appears to retreat with time and the Gulf High appears to move north and be expanding eastward. I do not see any resurgent energy moving east and dropping into what looks like a pretty benign 582 Hudson Bay low. In fact at or prior to 120 hours, there is NO Hudson Bay low and all that remains is a trapped 576 low off New England (at about 40N). All the while, the Gulf Upper High is pushed well into the Midwest, the Atlantic tropical ridge appears to be surging westward and the entire West Atlantic and NE U.S. is practically under one large anticyclonic midlevel flow. By 144 hour, the New England cut-off begins to be pulled up and out.
If the forecasted mid level ridging confirms (not unrealistic given that it is the middle of August), than it is my contention that the GFS is overplaying the closed cut-off low off New England. I do not think that it will break down such ridging (if it truly takes place), and this would lend for a system that is already in the Central Caribbean, to track further west where greater OHC exists and ultimately appear to steer such a system under a more dominant ridge toward perhaps the Texas or W. Louisiana coastline. Now, should a T.S. form a bit further north, than its development will likely be hindered by land (until perhaps reaching 80W?). Still seems that the result would remain more or less the same. Obviously I could be wrong and a deeper trough could degrade the ridging over the N. Caribbean, in which I suppose a system might "pop" north of Central or W. Cuba. Could be a scenario for a stall though, with the eventual retreating E. Coast trough, followed by a slow WNW or NW motion under a building ridge.