DOC: GEFS example

[raybellwaves]

Closes #37

[andersy005]

Thank you for putting this together, @raybellwaves! To fix the linting issue, could you enable pre-commit locally with pre-commit install and then run pre-commit run --all-files. (pre-commit should be installed if you set up the local dev environment).

Also, could we put this example under its own sub-heading. Currently, it's under the caching heading and it would be better to have a separate heading for it. @aaronspring, any thoughts on what this new sub-heading could be?

[aaronspring]

Advanced example with cfgrib?

[aaronspring]

I think Anderson meant a ## subheading.

Multi-file concat_kwargs cfgrib

under ## caching

[aaronspring]

I now realise that my example wasn’t that super good. Only one dimension concationated. Wouldn’t actually require concat_kwargs IMO.

path = "NCEP gens-a Grid 3 Member-Forecast -3 for 2020-08-31 00:00*" (haven’t tried)

could maybe concat 21 number and a few steps.

[raybellwaves]

I now realise that my example wasn’t that super good. Only one dimension concationated. Wouldn’t actually require concat_kwargs IMO.

path = "NCEP gens-a Grid 3 Member-Forecast -3 for 2020-08-31 00:00*" (haven’t tried)

could maybe concat 21 number and a few steps.

multi-dim concat is probably out of the scope here.

Been a while since I looked at that (https://stackoverflow.com/questions/47545138/python-xarray-open-mfdataset-concat-along-two-dimensions ; https://stackoverflow.com/questions/51487206/combining-spatial-netcdf-files-using-xarray-python/59377471#59377471)

@andersy005 this good to go?

[andersy005]

This looks great, @raybellwaves! The CI failures are unrelated. Merging this shortly