diff --git a/physics/module_bl_mynn.F90 b/physics/module_bl_mynn.F90
index 943a5c81d..18a385ba7 100644
--- a/physics/module_bl_mynn.F90
+++ b/physics/module_bl_mynn.F90
@@ -1,5 +1,5 @@
 !>\file module_bl_mynn.F90
-! This file contains the entity of MYNN-EDMF PBL scheme.
+!! This file contains the entity of MYNN-EDMF PBL scheme.
 ! **********************************************************************
 ! *   An improved Mellor-Yamada turbulence closure model               *
 ! *                                                                    *
diff --git a/physics/module_sf_mynn.F90 b/physics/module_sf_mynn.F90
index 17f682218..c2845f290 100644
--- a/physics/module_sf_mynn.F90
+++ b/physics/module_sf_mynn.F90
@@ -1380,6 +1380,8 @@ SUBROUTINE SFCLAY1D_mynn(flag_iter,                            &
        else
           ZNTstoch_lnd(I)  = ZNT_lnd(I)
        endif
+       !add limit to prevent ridiculous values of z0 (more than dz/15)
+       ZNTstoch_lnd(I) = min(ZNTstoch_lnd(I), dz8w1d(i)*0.0666)
 
        !--------------------------------------
        ! LAND