diff --git a/met/src/libcode/vx_data2d_nccf/nccf_file.cc b/met/src/libcode/vx_data2d_nccf/nccf_file.cc
index 7ccdd710ae..dbe5e4e323 100644
--- a/met/src/libcode/vx_data2d_nccf/nccf_file.cc
+++ b/met/src/libcode/vx_data2d_nccf/nccf_file.cc
@@ -2430,10 +2430,12 @@ void NcCfFile::get_grid_mapping_rotated_latitude_longitude(const NcVar *grid_map
 
   data.name = rotated_latlon_proj_type;
 
-  // Derive south pole location from the north pole
+  // Derive south pole location from the north pole:
+  // - Reverse the sign of the latitude
+  // - Add 180 to the longitude and switch from degrees east to west
   data.true_lat_south_pole = -1.0 * get_att_value_double(grid_np_lat_att);
   double np_lon = rescale_lon(get_att_value_double(grid_np_lon_att));
-  data.true_lon_south_pole = rescale_lon(-1.0 * (180.0 - fabs(np_lon)));
+  data.true_lon_south_pole = rescale_lon(-1.0 * (np_lon + 180.0));
 
   // Copied from the LatLon data structure
   data.rot_lat_ll = ll_data.lat_ll;