diff --git a/WRF.md b/WRF.md
index 838bb791e4f2ee1d79fd1581ba6fc15242b44279..db2d22a2e312ad7ee9d0b70169fa501cea834527 100644
--- a/WRF.md
+++ b/WRF.md
@@ -74,7 +74,7 @@ ln -s $WPS_PATH/met_em* .
 ./wrf.exe
 ```
 
-To do the WRF pre-processing for a real-case simulation getting initial and boundary conditions from ECMWF-IFS data on model levels, you could use a script such as the following. However, it depends on namelists, variable tables and other settings files being correctly specified. See below for details.
+The `met_em*` files linked in this snipped are the outcome of the WRF preprocessing (interpolation of initial and boundary conditions from another model, or from reanalyses, on the WRF grid). The WRF preprocessing system (WPS) is a separate set of executables, that can be built only after WRF is successfully compiled. To run WPS for a real-case simulation, getting initial and boundary conditions from ECMWF-IFS data on model levels, you could use a script such as the following. However, it depends on namelists, variable tables and other settings files being correctly specified. See below for details.
 
 ```sh title="Example: wrf-run-script.sh"
 #!/bin/bash