It looks like you went ahead and booked another ticket already. If enough flights cancel they may set up an extra section, though I doubt they'll have the extra aircraft for it around this holiday.

There's no way to predict what would happen, and since it would be a weather-related IROP you wouldn't be owed much other than the next available seat on the next available flight. That could be the next day or even a few days later. JetBlue has very few domestic partners and I don't think any of them will help get you to Jamaica from New York.

If it's any consolation, JFK is in Jamaica, NY. So in a sense you are already there

-J.