Ernesto's central pressure has been a bit unconventional for a tropical storm. His lowest pressure has been near 1006 MB, not all that impressive. His winds and cyclonic spin were baroclinically enhanced by high pressure located N and another W of the system. Now that those relationships are weakening, Ernesto has to power himself via tropical means (oceanic heat) if he wants to succeed going forward.
Here is a Water Vapor image showing Ernesto (South) and an open Tropical Wave affecting FL. So, why would Ernesto not simply be a bigger version of the FL Tropical Wave?
|Source: Univ of Wisconsin SSEC|