I believe this 5-day forecast precip map tells the tale for a significantly large area to be affected by Gustav as it slows down and rains itself out over Louisiana.
5 day precip fcst
Visible imagery continues to show Gustav moving NW along forecast track and at least maintaining, if not increasing, in strength. The next 12-18 hours will determine whether we're looking at a cat 3 or cat 4 storm -- either way, it's a major hurricane.