I would love rain over the 10 inches I had to shovel out of our driveway yesterday.
That said, it is impossible to forecast with any accuracy more than a couple days out and even that is difficult. That is the computer's best guess. I also look at it, knowing this, and watch it change on a daily basis as more and more information comes in. I fret, I stew and I worry, but in the end it is what it is and I pack for every eventuality (spare shoes and ponchos).
We have had rain forecast every trip to WDW. I was sprinkled on one night out of all the trips we have gone.
Local forecasts are somewhat better, since these are people who live there and have experience with what can happen. But they don't do more than forecase about 5 days out, and again, past a day or two it is all based on computer models.
My DS loved weather, and loved snow days. One year, we had a lot of snow and he proved better than any weatherman predicting when and how much it would snow. His teacher said she trusted him more than what she saw on TV. Then he started thinking about it and looking at the models, and stopped trusting his gut feeling - never the same after that. So I figure sometimes the more you know, the harder it is to predict. Which is why I prepare for everything.