The raw files produced by WRF need to be postprocessed to make them ?CF-compliant. But this is conveniently carried out after the simulations are finished. However, for users that do not have large storage resources, the whole WRF raw files on an experiment can be too heavy. In fact, by default, WRF saves many variables, and these files are large. Thus, WRF4G provides the possibility of passing the WRF raw output files through a post-processing script as WRF is running, using the local grid resources.
Similar to preprocessor, WRF4G postprocessor is an executable script that can be written in any programming language, provided it does accept one argument.