Grib2 is a moving target, with new developments and applications.
David Burch explains some of them in his blog - David Burch Navigation Blog
- see the article "NDFD: Oceanic, CONUS, and Regional".
The article states that OpenCPN
does not support Grib2, see a discussion here -David Burch Navigation Blog: International List of Weather Services
. Check the end of the page.
does support grib2 with the file extensions of .grib2 and .grb2 if they are in a "in a plain Lat-Lon grid" or Mercator projection.
To fully support NDFD, especially the CONUS part, OpenCPN needs to be able to read
*Lamberts Conformal Conical Projection
*The .bin file format
This is definitely something to consider for OpenCPN 4.8.