Welcome to Disboards.
Weather forecasts get less accurate as you get further away and are virtually worthless more than 7 days out. You are looking at nearly two weeks. And as far as a forecast of thunderstorms, it wouldn't mean it is going to rain all day every day. It storms in the Bahamas, sometimes a quick one blows through, sometimes you get plenty. It certainly doesn't mean anything is "going on", it's weather on islands in the ocean.
Enjoy your cruise!