It's not free, but for less than the cost of that last latte you bought, you can have it! The app is called "Dark Sky" - search for it on your app store.
So you can see what it does, here's a look at some of the screens. First, the current forecast for your location, for the next 60 minutes:
This view is shrinkable to show the whole world, or you can zoom in to show your location in great detail. In the zoomed-out view, the time scale changes to days instead of hours, and you will get a couple of days to the future of the 'now' point - that is, a predicted radar loop. It can also show a loop on temperature, but I find that less interesting.
Now tell me that you wouldn't find this handy on board!