There is a lot of great free weather data out there but it is hard and expensive to use. The NBM and GFS datasets are among the best. There are many companies deriving and re-packaging it for a price. GribStream is faster for a fraction of the price. Make sure to query as many coordinates as you need in the same request and you are good to go. And you can also get access to the full forecast history with features like "as-of" or "time-travel" so you can backtest the accuracy of the forecasts and any models that you derive.