"The second percentage refers to the entire 5-day period, not days 3-5. So if the 48-hr percentage is the same as the 5-day percentage (as it is in this case), that means that any expected development is going to occur sooner rather than later."

"And if it develops into a tropical cyclone again it would be called Dorian."

"Maintaining a closed circulation has never been a requirement for name-retention within a basin, Timothy."

"The NWS Directive states that "Within a basin, if the remnant of a tropical cyclone redevelops into a tropical cyclone, it is assigned its original number or name." This language is a little ambiguous about what happens when there is more than one remnant (if, for example, a low-level remnant and a mid-level remnant separate). However, in such a case, we follow the primary remnant, which would almost always be considered the lower-level feature.

The reason that 2005's TD Twelve was not renamed TD Ten was because the primary remnant - the low-level circulation - of TD Ten had moved on and was not involved in the genesis of TD Twelve. In the case of Dorian, on the other hand, we're still dealing with the same low-level vorticity feature."