diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6f473679..1afaaa07 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -104,6 +104,7 @@ if ( ${USE_MPI} )
   add_compile_definitions(
                           USE_MPI=1
                           DM_PARALLEL
+                          _MPI
                           )
 
   if ( DEFINED WRF_MPI_Fortran_FLAGS AND NOT "${WRF_MPI_Fortran_FLAGS}" STREQUAL "" )