diff --git a/Registry/Registry.EM_COMMON b/Registry/Registry.EM_COMMON
index 805636e152..f8d630bfa9 100644
--- a/Registry/Registry.EM_COMMON
+++ b/Registry/Registry.EM_COMMON
@@ -2465,6 +2465,7 @@ rconfig   integer km_opt_dfi              namelist,dynamics	max_domains   1
 rconfig   integer damp_opt                namelist,dynamics	1             0       irh    "damp_opt"              ""      ""
 rconfig   integer rad_nudge               namelist,dynamics	1             0       irh    "rad_nudge"             ""      ""
 rconfig   integer gwd_opt                 namelist,dynamics     1             0       irh    "gwd_opt"              ""      ""
+rconfig   real    max_rot_angle_gwd       namelist,dynamics     1             22.5    irh    "max_rot_angle_gwd"    "max projection rotation angle permitted for gwd_opt=1"      ""
 rconfig   real    zdamp                   namelist,dynamics	max_domains    5000.   h    "zdamp"         ""      ""
 rconfig   real    dampcoef                namelist,dynamics     max_domains    0.      h    "dampcoef"              ""      ""
 rconfig   real    khdif                   namelist,dynamics	max_domains    0       h    "khdif"         ""      ""
diff --git a/dyn_em/start_em.F b/dyn_em/start_em.F
index 0fffbcdb4f..83e9033e38 100644
--- a/dyn_em/start_em.F
+++ b/dyn_em/start_em.F
@@ -142,7 +142,7 @@ SUBROUTINE start_domain_em ( grid, allowed_to_read &
 !  CCN for MP=18 initializatio
    REAL :: ccn_max_val
 
-   REAL :: max_mf
+   REAL :: max_mf, max_rot_angle
    CALL get_ijk_from_grid ( grid ,                              &
                            ids, ide, jds, jde, kds, kde,        &
                            ims, ime, jms, jme, kms, kme,        &
@@ -161,6 +161,36 @@ SUBROUTINE start_domain_em ( grid, allowed_to_read &
    ALLOCATE(z_at_q(IMS:IME,KMS:KME,JMS:JME),STAT=I)  ; z_at_q = 0.
    CALL model_to_grid_config_rec ( grid%id , model_config_rec , config_flags )
 
+   !  If the rotation angle is too large, the GWD option does not do well with the assumed U and V
+   !  being close to earth relative.
+
+   IF ( ( grid%id .EQ. 1 ) .AND. ( config_flags%gwd_opt .EQ. 1 ) ) THEN
+      max_rot_angle = ASIN(ABS(grid%sina(its,jts)))/DEGRAD
+      DO j=jts,MIN(jde-1,jte)
+         DO i=its,MIN(ide-1,ite)
+            max_rot_angle = MAX ( max_rot_angle , ASIN(ABS(grid%sina(i,j)))/DEGRAD )
+         END DO
+      END DO
+#if ( defined(DM_PARALLEL)  &&   ! defined(STUBMPI) )
+      max_rot_angle = wrf_dm_max_real ( max_rot_angle )
+#endif
+      IF ( max_rot_angle .GT. ABS(config_flags%max_rot_angle_gwd) ) THEN
+         WRITE ( a_message , FMT='(A,F5.2)' ) 'Max projection rotation angle for domain 1 = ',max_rot_angle
+         CALL wrf_message ( a_message ) 
+         WRITE ( a_message , FMT='(A)'      ) 'This projection may not be appropriate for using the gravity wave drag option.'
+         CALL wrf_message ( a_message ) 
+         WRITE ( a_message , FMT='(A)'      ) 'In namelist.input make one of the two following changes:'
+         CALL wrf_message ( a_message ) 
+         WRITE ( a_message , FMT='(A)'      ) ' 1) gwd_opt = 0 '
+         CALL wrf_message ( a_message ) 
+         WRITE ( a_message , FMT='(A,F5.2)' ) ' 2) max_rot_angle_gwd > ',max_rot_angle
+         CALL wrf_message ( a_message ) 
+         WRITE ( a_message , FMT='(A)'      ) '--- ERROR: gwd_opt does not work with this domain'
+         CALL wrf_error_fatal ( a_message ) 
+      END IF
+   END IF
+
+
    IF ( ( MOD (ide-ids,config_flags%parent_grid_ratio) .NE. 0 ) .OR. &
         ( MOD (jde-jds,config_flags%parent_grid_ratio) .NE. 0 ) ) THEN
       WRITE(message, FMT='(A,I2,":  Both MOD(",I4,"-",I1,",",I2,") and MOD(",I4,"-",I1,",",I2,") must = 0" )') &