It's true, most weather forecasts any further than 3 days out are a best guess. Mostly longer range forecasting is only capable of showing trends or the possibility of precip in a broad area, etc. There is no way at all to pinpoint specific info that far out. The latest run of the GFS computer model paints rain over eastern Iowa all day next Saturday. My guess is the next run will show dry weather. That is why weather forecasting is so difficult. Plus that is just one of several models used to comprise a forecast. Weather is a complicated thing.