To fix this, you will need to re-run metgrid.exe, using an edited METGRID.TBL. This file is located in the WPS/metgrid directory. Search for 'RH' and edit the following line in the section, to say:
fill_lev=200100:const(91)
Alternatively, when you run real.exe, add the following line in the &domains section of the namelist:
use_surface = .false.
The problem is that the surface moisture field is filled with value 0, and when doing vertical interpolation, that affects the lowest model level. Either of the above can help with the problem. We will be looking for a more permanent fix in the future.
fill_lev=200100:const(91)
Alternatively, when you run real.exe, add the following line in the &domains section of the namelist:
use_surface = .false.
The problem is that the surface moisture field is filled with value 0, and when doing vertical interpolation, that affects the lowest model level. Either of the above can help with the problem. We will be looking for a more permanent fix in the future.