Just a bit of hurricane fact here.
The northeast quadrant of any hurricane is the most destructive. Since Hurricane Dean is expected to skirt the southern edge of Jamaica, nearly all of the island wll be subject to it's strongest winds.
Right now, Dean is a strong category 4 and expected to reach cat 5, the strongest level, and that speaks only of it's wind speed. That does not account for it's storm surge (ocean wave heights) that can reach 40-50 feet (17 meters or so) or perhaps more.
Jamaica is in for a real pounding, and even though I don't think they sit below sea level as New Orleans does, they will still see some flooding. I hope I am wrong.