But, since it may be slightly relevant, I'll go into a bit of detail on that jet model and why the Western Caribbean may be more favorable for development for T.D. #3 for yet another reason other than the fast forward movement of the storm.

Essentially, what you have in the Central Caribbean is a low-level easterly jet, with winds about 20mph in low levels moving from east to west. At the low levels, you want converging air for rising motion - as the air comes together, it rises - with corresponding diverging air at the upper levels. Note that the upper-level jet is the more common model of the two, but the low-level jet is the one Dr. Lyons discussed and is thus the one I'm talking about as well.

The simplified equations of motion, which I will spare you all from, say that if you go from a region of lower winds into a region of higher winds as you move to the west, there must be a transverse wind to compensate going from north to south. Thus, you have winds diverging in the north and converging in the south. Similarly, on the western end of the jet, going from a region of higher winds to lower winds, you must get a transverse wind (called an ageostrophic circulation in both cases) going from south to north. This creates divergence on the south side and convergence on the north side of the jet axis.

So, here, picture the NW Caribbean and SE Caribbean favored for rising motion - at least at the low levels - and the NE and SW Caribbean favored for sinking motion (again, at least at the low levels). Thus, the so-called four quadrant model. But, there is an important consideration to take into account - curvature. In the Northern Hemisphere, the impacts are enhanced in the northern half of the jet and diminished in the southern half. To some degree - and for simplicity to the general public, what Dr. Lyons did on TWC - you can just consider the impacts of the northern half.

What this leaves you with is a region favored for synoptic-scale (~1000km length-wise scale) descent in the eastern/central Caribbean and a region favored for synoptic-scale ascent in the western/central Caribbean. Again, I should note that this is just one piece to the puzzle - the low levels - and that the broader picture of upper-level flow and many other non-related (and some related) factors must be considered. Also, it's not something you generally see applied to the tropics - it is more of an idealized midlatitude theory - though it does have some application in the tropics. But, as one piece of the puzzle, it is one that can be useful for gaining *some* insight into the picture.