[gradsusr] netcdf to grib

[Zilore Mumba]

Excuses for posting what may be a very simple issue or an issue
already tackled. I have searched and have not found the answer. I have
WRf output in NetCdf format. WRF have a software ARWpost to convert
the files for working in grads. This software is too heavy for my
system.
With sdfopen I get the error below.
Is there a solution to this?
Thanks for assistance
Zilore
 ga-> sdfopen wrfout_d01_2011-11-19_00:00:00
Scanning self-describing file:  wrfout_d01_2011-11-19_00:00:00
gadsdf: SDF file has no discernable X coordinate.
ga->