If you direct your AWIPS II repo (/etc/yum.repos.d/awips2.repo) to point to https://www.unidata.ucar.edu/repos/yum/awips2-dev/ (rather than https://www.unidata.ucar.edu/repos/yum/awips2/) you can install the latest development build of AWIPS II (currently 14.4.1-5n13), which has limited support for MRMS (Multi-Radar/Multi-Sensor) products available as grids.