alt Catalog http://mtarchive.geol.iastate.edu/thredds/catalog/mtarchive/2013/10/15/grib2/ncep/NAM218/catalog.html

Dataset Size Last Modified
     Folder  NAM218   --
         Folder  18/   --
         Folder  12/   --
         Folder  06/   --
         Folder  00/   --

ISU MTArchive at ISU MTArchive see Info
THREDDS Data Server [Version 4.6.14 - 2019-07-23T11:04:31-0600] Documentation