Think of it this way, every person on this board has a different opinion on Disney, they like different things they see things differently at the various parks, resorts, etc. The "facts" of Disney are all the same, the layout of the parks, how the rides run, etc. but everyone interprets things differently. Take that over to weather and the weather people look at 20 different computer models all telling them something slightly different. Each forecaster is going to interpret them slightly differently too.
Our last storm was supposed to hit our town the hardest at the beginning of the tracking period. Well, the storm didn't move as fast as predicted at first, then it shifted the track some and the worst hit to the west of us. Weather predictions just aren't that perfect yet.