WRF Preprocessing System Version 3.8.1: Known Problems
NCEP NAM Complex Packaging Read Problems (posted 3/29/2017):
Problem: The packaging of files for NCEP NAM Grib2 files was changed the week of 20 March 2017. The WPS system has troubles reading in the height field correctly.
Solution: This fix is ONLY for users who are having troubles reading NCEP NAM Grib2 files. Download this packaged ungrib file and unpack it in the WPS/ directory. Included is a README.bugfix file (for your information), and another ungrib_fix.tar file. Unpackage that file and it will overwrite the problem file with a corrected version in the ungrib directory tree.