It comes directly from the National Weather Service. The forecasts are automatically downloaded though a SOAP service provided by the NWS and cached in a database. Everytime you enter a new location, we get the coordinates for your location from Google and then get the forecast from our database.
If you're the first person to request a certain location we have to ask Google for the exact geographic coordinates. They have a nice Geocoding API that allows us to do this. Your location and the matching coordinates are then cached in case anyone ever asks for it again. That's why after the first request the subsequent pages will load almost instantaneously.
I created this site because I was sick of trying to use weather.com or accuweather to get my forecast. Those sites are bloated with advertising and unnecessary information, and it takes way to long to find what I need. I'm constantly adding features and tweaking things so that my sites is more useful to me than the competition. That's my goal.