Version 3.4 of the WRF Pre-Processing System (WPS) was released on April 6, 2012.

WPS Version 3.4

Problem using GFS real-time data since May 22, 2012

Problem: NCEP has updated its real-time GFS GRIB2 files, beginning 2012-05-22_12:00:00. This is causing ungrib to extract incorrect data (at 80 m above surface) for surface fields. If your domain includes a pole or the Prime Meridian (0 longitude), program real may abort. If your domain lies elsewhere, the real program may not abort, but you will likely get incorrect surface fields (e.g. stronger surface winds). (If you download the V3.4 WPS tar file after June 5, 2012, the correction is already in the tar file.)

Solution: A file (rd_grib2.F) needs to be replaced in the /WPS/ungrib/src directory. This new file contains a solution to the problem. Replace the old file with the new and recompile WPS (no need to reconfigure).