I was not sure which site you were referring to. So, here is what to look for on the following site.
Go to ftp://weather.noaa.gov/SL.us008001/ST.opnl/
In this "folder" you will see a list of various models and runs of the models.
Hear is a list of the ETA model files.
09/17/2004 01:41AM Directory MT.eta_CY.00
01/28/2002 12:00AM Directory MT.eta_CY.03
09/17/2004 07:17AM Directory MT.eta_CY.06
09/16/2004 01:42PM Directory MT.eta_CY.12
09/16/2004 07:16PM Directory MT.eta_CY.18
Select which run of the model you want.
You will then see a file like the following:
09/16/2004 02:49PM Directory RD.20040916
Click on it.
You will then see the following:
09/16/2004 03:23PM Directory PT.grid_DF.bb
09/16/2004 03:04PM Directory PT.grid_DF.gr1
09/16/2004 03:03PM Directory PT.sndn_DF.buf
09/16/2004 03:13PM Directory PT.text_GP.tratcf
You will now see a list of GRIB files like the following:
09/16/2004 01:49PM 46,299,848 fh.0006_tl.press_gr.awip12
09/16/2004 01:48PM 7,866,894 fh.0006_tl.press_gr.awip20
09/16/2004 01:47PM 15,459,658 fh.0006_tl.press_gr.awip3d
09/16/2004 01:47PM 9,564,262 fh.0006_tl.press_gr.awipak
09/16/2004 01:48PM 1,105,072 fh.0006_tl.press_gr.awp211
09/16/2004 01:45PM 85,846,072 fh.0006_tl.press_gr.egrdsf
09/16/2004 01:49PM 9,068,020 fh.0006_tl.press_gr.grbgrd
09/16/2004 03:02PM 1,234,052 fh.0006_tl.press_gr.icwf20
09/16/2004 03:02PM 308,488 fh.0006_tl.press_gr.icwf3d
I usually select the awp211 files. They are the smallest of the files in size available and offer forecast for every 6 hours. Some of the files offer forecast for every 3 hours but they are a little bigger.
For GFS files I use the following site:
http://nomads.ncdc.noaa.gov/data-access ... r_datasets
Hope this helps.