[Wrf-users] Problems with copygb

[Justin Arnott]

Hi Folks,

I am using the copygb utility to regrid some WRF precip (variable: 
apcpsfc) output onto a common grid with another dataset (NCEP Stage 4 
precip) for a verification study.  I noticed that for certain time 
periods (e.g. forecast hour 1) the grib output using bilinear 
interpolation to the new grid gives me a constant "0" field, even though 
the apcpsfc field in the original grib file is nonzero.  My command line 
input follows:

copygb -g"255 0 86 43 40000 276000 128 45880 287900 140 140" -x 
2007020700_BGM-ARW.F00100.grb out.grb

The grb file is a 1 hour output file from WRF.  Interestingly, other 
fields, such as tmpprs or prmslmsl seem to go work fine.
Thinking that the interpolation type might have caused the problem, I 
asked for no interpolation using:

copygb -x 2007020700_BGM-ARW.F00100.grb out.grb

This still gives me a resultant precip field that is filled with zeroes.

Does anyone see anything wrong with my input or how I'm using copygb?  I 
appreciate your help in advance.

Justin Arnott
NWS Binghamton