[python #UNG-652401]: MetPy Mondays #164 - (MetPy 1.0 XArray Basics with the GFS): Unable to open netCDF stream

Hello! Thanks for reaching out, and thanks for providing helpful information.

Unfortunately, I don't have a concrete solution to your problem. This is 
something I am not able to recreate locally with your provided notebooks and 
environment information. We can try a few things here to get a better idea of 
where this is coming from.

Just in case there are some package issues in your base environment, let's 
start with a fresh install of only the tools we need to reproduce this:

  conda create -n test-env -c conda-forge jupyterlab metpy siphon
  conda activate test-env
  jupyter lab

and then give your notebook another try. If you're still getting an error, then 
follow back up with me and let me know the error, as well as the output from 
`conda list` once again!

Some other things we can check out if you're still getting this error. From 
your command-line (within your environment!):

  nc-config --version --prefix --has-dap2
  ncdump -h 
'https://thredds.ucar.edu/thredds/dodsC/grib/NCEP/GFS/Global_0p25deg/Best'

and let me know the output of nc-config and if ncdump works in reaching this 
file for you. These can tell us if something is in the wrong place 
behind-the-scenes with netcdf, or if there might be some other reason you can't 
access this OPeNDAP link.

Separately, back in your notebook we can give an explicit try with the 
CDMRemote protocol on THREDDS:

  from siphon.catalog import TDSCatalog
  import xarray as xr

  url = 
('https://thredds.ucar.edu/thredds/catalog/grib/NCEP/GFS/Global_0p25deg/catalog.xml')
  cat = TDSCatalog(url)
  d = cat.datasets['Best GFS Quarter Degree Forecast Time Series']
  ds = d.remote_access(service='CDMRemote', use_xarray=True)
  ds

and let me know if that works. Finally, for some people, shrinking the cache of 
file-like objects for xarray might help:

  import xarray as xr
  xr.set_options(file_cache_maxsize=10)
  . . . # (remainder of your notebook)

Hopefully this is just an issue in your base environment, but don't hesitate to 
follow up with the results of this testing so that we can find a solution!


All the best,

Drew


> Unfortunately, by following the 'MetPy Mondays session #164' (MetPy 1.0 
> XArray Basics with the GFS) I steadily encounter some error to open the 
> netCDF data stream.
> The finally returned error message is
> "[Errno -68] NetCDF: I/O failure: 
> b'https://thredds.ucar.edu/thredds/dodsC/grib/NCEP/GFS/Global_0p25deg/Best'"
> 
> I tried opening the netCDF data stream by using any of the THREDDS access 
> protocols available (OPENDAP,WCS,WMS,...), but none of them worked.
> The error occurs on both Windows 10 x64 and Linux (Linux Mint 20.2). On Linux 
> there's an additional curl error (Unsupported protocol).
> 


Ticket Details
===================
Ticket ID: UNG-652401
Department: Support Python
Priority: Low
Status: Closed
===================
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