diff --git a/diag_manager/diag_output.F90 b/diag_manager/diag_output.F90
index ed0a2d4bd2..0913b256a8 100644
--- a/diag_manager/diag_output.F90
+++ b/diag_manager/diag_output.F90
@@ -70,7 +70,7 @@ MODULE diag_output_mod
   PRIVATE
   PUBLIC :: diag_output_init, write_axis_meta_data, write_field_meta_data, done_meta_data,&
        & diag_fieldtype, get_diag_global_att, set_diag_global_att
-  PUBLIC :: diag_field_write, diag_write_time !< use_mpp_io = .false.
+  PUBLIC :: diag_field_write, diag_write_time, diag_flush
   TYPE(diag_global_att_type), SAVE :: diag_global_att
 
   INTEGER, PARAMETER      :: NETCDF1 = 1
@@ -1364,6 +1364,27 @@ SUBROUTINE set_diag_global_att(component, gridType, tileName)
     diag_global_att%tile_name = tileName
     ! endif
   END SUBROUTINE set_diag_global_att
+
+  !> @brief Flushes the file into disk
+  subroutine diag_flush(file_num, fileobjU, fileobj, fileobjND, fnum_for_domain)
+    integer,                                   intent(in) :: file_num        !< Index in the fileobj* types array
+    type(FmsNetcdfUnstructuredDomainFile_t),intent(inout) :: fileobjU(:)     !< Array of non domain decomposed fileobj
+    type(FmsNetcdfDomainFile_t),            intent(inout) :: fileobj(:)      !< Array of domain decomposed fileobj
+    type(FmsNetcdfFile_t),                  intent(inout) :: fileobjND(:)    !< Array of unstructured domain fileobj
+    character(len=2),                          intent(in) :: fnum_for_domain !< String indicating the type of domain
+                                                                             !! "2d" domain decomposed
+                                                                             !! "ug" unstructured domain decomposed
+                                                                             !! "nd" no domain
+    if (fnum_for_domain == "2d" ) then
+       call flush_file (fileobj (file_num))
+    elseif (fnum_for_domain == "nd") then
+       call flush_file (fileobjND (file_num))
+    elseif (fnum_for_domain == "ug") then
+       call flush_file (fileobjU(file_num))
+    else
+       call error_mesg("diag_field_write","No file object is associated with this file number",fatal)
+    endif
+  end subroutine diag_flush
 END MODULE diag_output_mod
 !> @}
 ! close documentation grouping
diff --git a/diag_manager/diag_util.F90 b/diag_manager/diag_util.F90
index fb8f236f4c..07ad463c03 100644
--- a/diag_manager/diag_util.F90
+++ b/diag_manager/diag_util.F90
@@ -58,7 +58,7 @@ MODULE diag_util_mod
        & get_axes_shift, get_diag_axis_name, get_diag_axis_domain_name, get_domainUG, &
        & get_axis_reqfld, axis_is_compressed, get_compressed_axes_ids
   USE diag_output_mod, ONLY: diag_output_init, write_axis_meta_data,&
-       & write_field_meta_data, done_meta_data
+       & write_field_meta_data, done_meta_data, diag_flush
   USE diag_output_mod, ONLY: diag_field_write, diag_write_time !<fms2_io use_mpp_io=.false.
   USE diag_grid_mod, ONLY: get_local_indexes
   USE fms_mod, ONLY: error_mesg, FATAL, WARNING, NOTE, mpp_pe, mpp_root_pe, lowercase, fms_error_handler,&
@@ -2299,6 +2299,7 @@ SUBROUTINE diag_data_out(file, field, dat, time, final_call_in, static_write_in,
        END IF
     ELSE
        IF ( time > files(file)%last_flush .AND. (flush_nc_files.OR.debug_diag_manager) ) THEN
+          call diag_flush(file, fileobjU, fileobj, fileobjND, fnum_for_domain(file))
           files(file)%last_flush = time
        END IF
     END IF
diff --git a/fms2_io/fms2_io.F90 b/fms2_io/fms2_io.F90
index ce01f0739c..d82be39148 100644
--- a/fms2_io/fms2_io.F90
+++ b/fms2_io/fms2_io.F90
@@ -104,6 +104,7 @@ module fms2_io_mod
 public :: get_instance_filename
 public :: nullify_filename_appendix
 public :: string2
+public :: flush_file
 !> @}
 
 !> @brief Opens a given netcdf or domain file.
diff --git a/fms2_io/netcdf_io.F90 b/fms2_io/netcdf_io.F90
index 70bd5a9c95..bf028d7819 100644
--- a/fms2_io/netcdf_io.F90
+++ b/fms2_io/netcdf_io.F90
@@ -233,6 +233,7 @@ module netcdf_io_mod
 public :: set_fileobj_time_name
 public :: write_restart_bc
 public :: read_restart_bc
+public :: flush_file
 
 !> @ingroup netcdf_io_mod
 interface netcdf_add_restart_variable
@@ -2265,6 +2266,16 @@ subroutine write_restart_bc(fileobj, unlim_dim_level)
 
 end subroutine write_restart_bc
 
+!> @brief flushes the netcdf file into disk
+subroutine flush_file(fileobj)
+  class(FmsNetcdfFile_t), intent(inout) :: fileobj !< FMS2_io fileobj
+
+  integer :: err !< Netcdf error code
+
+  err = nf90_sync(fileobj%ncid)
+  call check_netcdf_code(err, "Flush_file: File:"//trim(fileobj%path))
+end subroutine flush_file
+
 end module netcdf_io_mod
 !> @}
 ! close documentation grouping