I just want to comment a bit on the WV link you posted and elaborate a bit on my comments a little earlier.
There is clear evidence of the anti-cyclonic turn in the atmosphere which extends out to about 87 W and it will impact Gustav on the east very quickly. Gustave should then slide W or even a little south of West along the southern periphery of this high, along the southern coast of Cuba. The models have all grabbed this and that is how it should play out for the next several days.
That high is kind of blocked to its east and nothing seems to be moving too fast.
The trough in the midwest seems to me to be breaking down a bit, and even an anti cyclonic flow may be developing. This has been picked up on by the European model which keeps Gustave on the left of the track all the way to Mexico.
However, over the SW an upper low seems to be developing and there is a push of drier air down from the NW. If this pushes eastward in the next three days, this should have an effect on where Gustave goes.
The track looks good for three days, but beyond that ???

(personal reference removed.)