NOAA/ESRL/PSD Catalog http://esrl.noaa.gov/psd/thredds/catalog/Datasets/NARR/Monthlies/catalog.html

Dataset Size Last Modified
     Folder  Monthlies   --
         Folder  Derived/   --
         Folder  monolevel/   --
         Folder  pressure/   --
         Folder  subsurface/   --

NOAA/ESRL/PSD at NOAA ESRL PSD see Info
THREDDS Data Server [Version 4.3.15 - 20121218.1126] Documentation