Originally Posted by Copprhead
In what format are the .grb files? I cannot open them in MacENC or GPSNavX.
As I mentioned, these are GRIB v2 files. Some software isn't capable of viewing GRIB2, just check your documentation.
I have opened and tested the files though, and they are valid GRIB files.
For example, here's a screenshot from Jan 5 1990 around New Zealand showing valid data.