Don't worry about it too much. First of all if any of the forcast says "scattered" showers/t-storms then likely if you do get rain it won't be all day and you might not get any at all. Second, the more long-term the forecast, the less accurate it is.
A number of times I've returned from a vacation with beautiful weather and had people tell me that according to the weather report they had seen at home, we had had a lot of rain.
As someone else mentioned, even if you do get rain, at least it will be warm. We were at WDW last December and had a couple of pretty chilly days of non-stop pouring rain. I have to say, it was none too pleasant but it sure didn't ruin our trip.