I have been using the GFS model data to get soundings to assist me in the running of advanced gliding courses in Australia. I have been using the information for the last two years and, to date, I have been extremely impressed by the accuracy of the information. My query is, how is the information derived? The nearest sites that have sounding information are Moree, Charleville and Brisbane, the nearest being some 250km from my location. Many thanks for a great service.
NOAA's National Center's for Environmental Prediction (NCEP) run several gridded weather forecast models to predict the future weather conditions. The GFS model is their global model. You can find all the information you want about the model and NCEP at their website at http://www.emc.ncep.noaa.gov/, but in short, they take observations from the surface, upper-air, and aircraft and assimilation them into a 3D grid and then use equations of motion to predict where the weather systems will be in the future. When you produce a sounding on our (NOAA ARL) website, you are retrieving the model generated vertical profile of meteorological variables from the meteorological model.