Yet another illustration of why long-range forecasts are completely useless. Just like the Piedmont Pro-Am forecast that said "90% all weekend long" that turned out to be an absolutely picture perfect weekend. They said Saturday was going to be a wash, and now look at it.
It is scientifically impossible to accurately predict weather 5+ days out. Don't even bother looking at weekend forecasts until at least Tuesday afternoon. And don't ever bother with Accuweather.com. I've been tracking weather for race events for a couple of years now, and they are the worst, by far.
www.wunderground.com is the best resource.