omf should be Obs_Minus_Forecast_unadjusted

[HaixiaLiu-NOAA]

The omf plot currently is plotting the Obs_Minus_Forecast_adjusted which means omf after bias correction, which confuses user. I think the omf should be Obs_Minus_Forecast_unadjusted (omf before bias correction).

[HaixiaLiu-NOAA]

just one line of change in pyGSI/diags.py

change the following line
self.omf = f.variables['Obs_Minus_Forecast_adjusted'][:]

to
self.omf = f.variables['Obs_Minus_Forecast_unadjusted'][:]

[HaixiaLiu-NOAA]

it is better to add more variable plotting options to include both omfbc (adjusted=after bias correction) and omfnbc (unadjusted=before bias correction)).