Greetings!
The Unidata THREDDS group has started posting changes made to the
datasets distributed on thredds.ucar.edu. Currently, we are focused on
tracking changes made to our model output catalogs. The changes can be
found here:
http://www.unidata.ucar.edu/data/thredds_changes.html
The most recent change is the removal of the NAM 20km "surface" and
"selectsurface" grids. We will be maintaining this page to keep it
current as we add or remove datasets, or modify the availability of
datasets on thredds.ucar.edu.
Cheers,
Sean