Some answers from NOMADS email FAQs:

NOMADS capabilities:

NOMADS is a prototype (not operational) so data may not be available sometimes and should not be used for time critical needs.

The GFS 0.5 degree GRIB1 pressure grid files and other model output are on NOMADS servers in real time.

http://nomad3.ncep.noaa.gov
and the data set is also available from
http://nomad5.ncep.noaa.gov

In addition, a second real time copy is at
http://nomads6.ncdc.noaa.gov

The data entries are listed on tables at the above URL addresses on the pages /ncep_data or /data.html where a number of user/client applications can be found with other information.

The data sets are available by ftp.

Data sets are also available using "Fast ftp" (http://www.cpc.ncep.noaa.gov/products/wesley/fast_downloading_grib.html), which allows access by variable or level,  using cURL commands.

Regional sub-setting is available using ftp2u (ftp4u), in addition to selection by level and variable, and the results repackaged in a GRIB1 file sent (immediately) to your ftp server or ours for later download.

A DODS (OPeNDAP) server is operating on all the data sets returning values at one or more points from URL queries.   Human and machine readable metadata descriptions of all the holdings are available (click DODS and follow the prompts to the .info page) and proper queries return unpacked values with description/location information.  Using DAP, freeware grid analysis and display systems, such as GrADS, or commercial products, MATLAB, IDL, etc..., can directly connect to the matrix of data holdings and perform any command as if nomads disk storage was local to your computer.

A display capability is available with the pdisp(plot) application.

All these applications and services can be automated by using non-interactive web download commands, like wget, in a suitable unix script and placed in cron for automatic data flow.