Metcombine can optionally be run before Premobl. If used, Metcombine must be run for each individual meteorology file you need to create. For example, if you have five days worth of meteorology data as one-day files, you’ll need to run Metcombine five times. If the meteorology variables you wish to use are already in the same file, then you do not need to use Metcombine.