Don't worry too much. When we were going in late April, I kept checking the weather and it said the same thing, showers or thunderstorms just about every day. First of all, it seemed to change every day the I looked at the weather, and secondly, when we were there, any rain we had didn't seem to last much more than an hour. One night we were going to Epcot, and it was pouring, so once we got into the parking lot, we sat in our car and talked until it stopped, about 40 minutes later, and off we went into the park, like it had never rained. I think the scattered thunderstorms are quite common in Florida this time of year, so don't let it ruin your plans. And usually they say a "chance" of a thunderstorm, so that doesn't mean it is definite!! Enjoy your trip. I'm jealous.... have to wait to September to go back