SYNOP data assimilation issue with WRFDAv4.5.2

[Litta]

Dear Sir/Madam

I am trying to assimilate AWS data. I used FM12-SYNOP format. I converted to Littler and successfully completed obsproc.exe, da_wrfvar.exe and da_update_bc.exe.
rsl.out.0000 file is showing 1073 station data sets are assimilated. But there is no difference between with and without assimilation plot.
Please give your suggestions.

Thanks and best regards,
Litta