diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9a2c599c9..888a622d9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -170,6 +170,7 @@ add_library(FV3::fv3 ALIAS fv3)
 
 set_property(SOURCE model/nh_utils.F90 APPEND_STRING PROPERTY COMPILE_FLAGS "${FAST}")
 set_property(SOURCE model/fv_mapz.F90  APPEND_STRING PROPERTY COMPILE_FLAGS "${FAST}")
+set_property(SOURCE tools/fv_diagnostics.F90  APPEND_STRING PROPERTY COMPILE_FLAGS "-O0")
 
 set_target_properties(fv3 PROPERTIES Fortran_MODULE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/include/fv3)
 target_include_directories(fv3 INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include/fv3>
diff --git a/tools/fv_diagnostics.F90 b/tools/fv_diagnostics.F90
index fbe960d86..7e278d81b 100644
--- a/tools/fv_diagnostics.F90
+++ b/tools/fv_diagnostics.F90
@@ -295,30 +295,29 @@ subroutine fv_diag_init(Atm, axes, Time, npx, npy, npz, p_ref)
 ! valid range for some fields
 
 !!!  This will need mods for more than 1 tile per pe  !!!
-     vsrange(1) = -200. ; vsrange(2) = 200.      ! surface (lowest layer) winds
-     rhrange(1) = -10. ; rhrange(2) = 150.       ! RH
-     slprange(1) = 800. ; slprange(2) = 1200.    ! surface (lowest layer) winds
-     skrange(1) = -10000000.0 ; skrange(2) = 10000000.0  ! dissipation estimate for SKEB
-
-    if (  Atm(1)%flagstruct%molecular_diffusion ) then
-     vrange(1) = -850. ; vrange(2) = 850.  
-     wrange(1) = -300. ; wrange(2) = 300.  
-     trange(1) = 5. ; trange(2) = 3500.  
-     vrange_bad(1) = -850. ;  vrange_bad(2) = 850.   
-     trange_bad(1) = 130. ; trange_bad(2) = 3500.  
+    vsrange = (/ -200.,  200. /)  ! surface (lowest layer) winds
+
+    if (Atm(1)%flagstruct%molecular_diffusion) then
+    vrange = (/ -850.,  850. /)  ! winds
+    wrange = (/ -300.,  300. /)  ! vertical wind
+    trange = (/    5., 3500. /)  ! temperature
+    vrange_bad = (/ -850.,  850. /)  ! winds
+    trange_bad = (/  130., 3500. /)  ! temperature
     else
-     vrange(1) = -330. ; vrange(2) = 330.  ! winds
-     wrange(1) = -100. ; wrange(2) = 100.  ! vertical wind
-     vrange_bad(1) = -250. ; vrange_bad(2) = 250. !winds 
+    vrange = (/ -330.,  330. /)  ! winds
+    wrange = (/ -100.,  100. /)  ! vertical wind
+    vrange_bad = (/ -250.,  250. /)  ! winds
 #ifdef HIWPP
-     trange(1) = 5. ; trange(2)=350.  ! temperature
-     trange_bad(1) = 130. ; trange_bad(2) = 350.  ! temperature
+    trange = (/    5.,  350. /)  ! temperature
+    trange_bad = (/   130.,  350. /)  ! temperature
 #else
-     trange(1) = 100. ; trange(2) = 350.  ! temperature
-     trange_bad(1) = 150. ; trange_bad(2) = 350.  ! temperature
+    trange = (/  100.,  350. /)  ! temperature
+    trange_bad = (/  150.,  350. /)  ! temperature
 #endif
     endif
-
+    rhrange = (/  -10.,  150. /)  ! RH
+    slprange = (/800.,  1200./)  ! sea-level-pressure
+    skrange  = (/ -10000000.0,  10000000.0 /)  ! dissipation estimate for SKEB
 
     ginv = 1./GRAV
      if (Atm(1)%grid_number == 1) fv_time = Time