diff --git a/model/fv_dynamics.F90 b/model/fv_dynamics.F90
index 4a9bab31a..8a723f7db 100644
--- a/model/fv_dynamics.F90
+++ b/model/fv_dynamics.F90
@@ -621,7 +621,9 @@ subroutine fv_dynamics(npx, npy, npz, nq_tot,  ng, bdt, consv_te, fill,
   mdt = bdt / real(k_split)
 
 #ifndef CCPP
-  if ( idiag%id_mdt > 0 .and. (.not. do_adiabatic_init) ) then
+  ! Routine Lagrangian_to_Eulerian expects dtdt_m to be allocated:
+  ! (fv_mapz.F90, 201): line real, intent(inout)::   dtdt(is:ie,js:je,km)
+  !if ( idiag%id_mdt > 0 .and. (.not. do_adiabatic_init) ) then
        allocate ( dtdt_m(is:ie,js:je,npz) )
 !$OMP parallel do default(none) shared(is,ie,js,je,npz,dtdt_m)
        do k=1,npz
@@ -631,7 +633,7 @@ subroutine fv_dynamics(npx, npy, npz, nq_tot,  ng, bdt, consv_te, fill,
              enddo
           enddo
        enddo
-  endif
+  !endif
 #endif
 
                                                   call timing_on('FV_DYN_LOOP')
@@ -834,10 +836,10 @@ subroutine fv_dynamics(npx, npy, npz, nq_tot,  ng, bdt, consv_te, fill,
        enddo
 !      call prt_mxm('Fast DTDT (deg/Day)', dtdt_m, is, ie, js, je, 0, npz, 1., gridstruct%area_64, domain)
        used = send_data(idiag%id_mdt, dtdt_m, fv_time)
+  endif
 #ifndef CCPP
-       deallocate ( dtdt_m )
+  deallocate ( dtdt_m )
 #endif
-  endif
 
   if( nwat == 6 ) then
      if (cld_amt > 0) then