Starting October 14, 2014 with the 12Z cycle, this directory will no longer be populated. 

NCEP Central Operations makes the same data available, operationally, on their ftp site.

Example URLs - note the date in the path:
http://ftpprd.ncep.noaa.gov/data/nccf/com/gfs/prod/gfs.2014100612/grib2.mdlsurgegrid.3km.12ala
http://ftpprd.ncep.noaa.gov/data/nccf/com/gfs/prod/gfs.2014100612/grib2.mdlsurgegrid.2.5km.12con

If you have any questions, please contact OPC at:
ncep.list.opc_web@noaa.gov


Change Log
2014-10-27: updated filename from grib2.mdlsurgegrid.12ala to grib2.mdlsurgegrid.3km.12ala
2014-10-27: updated filename from grib2.mdlsurgegrid.12con to grib2.mdlsurgegrid.2.5km.12con