TravelDancer- If the port is closed or damaged such that the ship cannot dock, then they will let you know in advance about the closing. If it is weather related, then those changes typically are last minute and they will notify you when you get to the ship. I would check to see if the cruise before yours goes to those ports. My feeling is that except for Costa Maya, your ports will be ok. Costa Maya may have to be closed.. Maybe they will stop in Cozumel instead... which would be better for you.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007