Well, I see a definite weak rotation. Unlike the previous attempts, convection is increasing during the morning hours. Additionally, the upper-air environment looks more favorable once the system enters the Caribbean Sea.
Shear is low, and the stable air mass has been gradually destabilizing. If convection maintains itself for another hour, I think it is a sign. The current parameters indicate that development should not occur before it enters the Caribbean, but the game will start once it clears the Windward Islands.
CIMSS shows low-level easterlies - this indicates the presences of a low-level ridge and a weak anticyclone. Some data indicates the western Atlantic trough should lift out - this system's future path depends upon two things:
1) The rate of development;
2) The pace of the trough as it pulls away from the Gulf of Mexico
Current shortwave shows the trough's rapid exit from the area. You can see the ridge "build" westward. Look at the large anticyclone over the western Caribbean and GOM. That should provide a good environment. Additionally, the GFS has been supporting this scenario in recent runs. Other models show a similar setup, too.
I think we have finally reached a critical point - IMO, this system will eventually develop to our next tropical cyclone. I think persistence payed off for this system - the NHC made a good call.
I'll offer more analyses...