@Vindaar sorry my mistake! I made the assumption that grib2 was a kind of HDF5 format. But the more I read into it - it looks like grib2 is a totally different beast.
As to why I'm doing this - I'm always looking for more performant ways of reading grib2s. They can get big, and many existing interfaces are slow. Regardless, thanks for offering your help. I'm probably either going with GDAL, or this neat thing called THREDDs. Hopefully nim will be in the mix, but I'm not sure now.
