I've never been to Kingston but I know the airport is out in open water and very exposed to storm surge. I guess on the positive side, the Montego Bay airport should be relatively protected on the north east side (at least from storm surge). The big issue is going to be the logistics of getting people and supplies between Montego Bay and high population places like Kingston. The already poor quality roads there might be completely destroyed if the torrential rain causes landslides.
When I was there last time, we did an ATV excursion up in the mountains in a Rastafarian village. They said the last time they had a significant hurricane (and nowhere as bad as this will be) they were cut off from the rest of civilization for weeks.