Chewing on things over here. Using Mark I eyeball, The storm is continuing to push ever so slightly north of the projected NHC path. As has been pointed out earlier, there is a slight bias in the later forecast time frames to the left (keeping the storm further left than projected). Couple that with storms rarely keeping such a straight as an arrow path (call it climatology and biases), and it's very easy to see why the NHC could be suspicious of the forecast paths on days 4 and 5. Toss in the model uncertainty (and if certain models don't hold onto the system, then how reliable are those models going to be?) and you have every reason to treat the forecast path on days 4 and 5 as little better than coin flips.

Of course, all this could be thrown out the window as the south east is literally baking underneath the high pressure (which is supposed to incidentally push Dean west to west north west) so it's quite possible that either the heat wave doesn't break a bit and dean continues the path, or something does come in and dean takes a more northerly course.

All of this is of course pointing towards a great 'i don't know' as far as where Dean is going. If i had to hazard any sort of guess, I'd say it's going to continue to track a hair to the right of the NHC path and come through just north of Jamaica, brush the western tip of Cuba and from there it's anyone's guess.

I'd also say it's not going to reach cat 5 (before entering the gulf) if it follows the path I think it will. simply too much interaction with land to wind up that hard. Now the biggest question that comes to mind, with all the heat content in the gulf, if it makes it in there relatively intact, with all that forward speed, there wont be time for any upwelling to hinder development, so it could simply slurp up all that energy and chug along like a freight train into somewhere, which also means if it keeps cruising along at 20+ MPH, it's going to get where it's going really quick. and people could get caught off guard in a very bad way (which is a nightmare scenario any way you look at it).