I rely upon my cell phone for hourly forecasts of rain and weather, but have not known how to get hourly forecasts more than 24 hours into the future. Yesterday a friend sent me the following National Weather Service link that forecasts hourly weather up to six days ahead. Of course, it loses precision, but still, sometimes you need to make decisions far into the future. All the usual radar maps and other information are on nearby clicks. All free and thanks to NOAA. Enjoy.
Alas, it only does forecasts for the US.