diff --git a/ProConPy/out_handler.py b/ProConPy/out_handler.py
index 078521a..315c4b5 100644
--- a/ProConPy/out_handler.py
+++ b/ProConPy/out_handler.py
@@ -1,11 +1,37 @@
 """ Logging Output Handler Module """
 
 import logging
+import sys
 import ipywidgets as widgets
 
 logger = logging.getLogger(__name__)
 
 
+class _NameStrippingFormatter(logging.Formatter):
+    """Formatter that drops the whitespace some logger names are padded with."""
+
+    def format(self, record):
+        name = record.name
+        record.name = name.strip()
+        try:
+            return super().format(record)
+        finally:
+            record.name = name
+
+
+def _console_handlers():
+    """INFO and below to stdout, WARNING and above to stderr, so that notebooks
+    (which show stderr on a red background) only flag actual warnings."""
+    formatter = _NameStrippingFormatter("%(levelname)s [%(name)s] %(message)s")
+    to_stdout = logging.StreamHandler(sys.stdout)
+    to_stdout.addFilter(lambda record: record.levelno < logging.WARNING)
+    to_stderr = logging.StreamHandler(sys.stderr)
+    to_stderr.setLevel(logging.WARNING)
+    for handler in (to_stdout, to_stderr):
+        handler.setFormatter(formatter)
+    return [to_stdout, to_stderr]
+
+
 class OutHandler(logging.Handler):
     """Custom logging handler sending logs to an output widget"""
 
@@ -17,7 +43,7 @@ def __init__(self, *args, **kwargs):
             "border": "1px solid black"
         }
         self.out = widgets.Output(layout=layout)
-        logging.basicConfig(level=logging.DEBUG, datefmt="%I:%M:%S")
+        logging.basicConfig(level=logging.DEBUG, handlers=_console_handlers())
         self.set_verbosity(verbose=False)
 
     def emit(self, record):
diff --git a/external/mom6_forge b/external/mom6_forge
index 83d40e2..89d8e67 160000
--- a/external/mom6_forge
+++ b/external/mom6_forge
@@ -1 +1 @@
-Subproject commit 83d40e2f63e1daaab3e007e14c3d1e27018209d4
+Subproject commit 89d8e67a76917a0d212da8db90517a7edc7ab24d
diff --git a/visualCaseGen/custom_widget_types/case_creator.py b/visualCaseGen/custom_widget_types/case_creator.py
index 892951b..cb6206e 100644
--- a/visualCaseGen/custom_widget_types/case_creator.py
+++ b/visualCaseGen/custom_widget_types/case_creator.py
@@ -521,6 +521,7 @@ def _run_create_newcase(self, caseroot, compset, resolution, do_exec):
             + f"--case {caseroot} "
             + f"--machine {machine} "
             + "--run-unsupported "
+            + "--handle-preexisting-dirs a "
         )
 
         # append pecount if provided:
@@ -549,7 +550,9 @@ def _run_create_newcase(self, caseroot, compset, resolution, do_exec):
 
         # Run the create_newcase command:
         if do_exec:
-            runout = subprocess.run(cmd, shell=True, capture_output=True)
+            runout = subprocess.run(
+                cmd, shell=True, capture_output=True, text=True, stdin=subprocess.DEVNULL
+            )
             with self._out:
                 if runout.returncode == 0:
                     print(f"{COMMENT}The create_newcase command was successful.{RESET}\n")
@@ -557,6 +560,12 @@ def _run_create_newcase(self, caseroot, compset, resolution, do_exec):
                     print(f"{ERROR}Error creating case.{RESET}\n")
                     print(f"{runout.stderr}\n")
             if runout.returncode != 0:
+                if "Aborting by user request" in runout.stderr:
+                    raise RuntimeError(
+                        "Error creating case: a previous case with the same name left its "
+                        "build/run directories behind (see the message above). Remove them, "
+                        "or choose a different case name."
+                    )
                 raise RuntimeError("Error creating case.")
 
     def _apply_all_xmlchanges(self, do_exec):
@@ -578,7 +587,6 @@ def _apply_all_xmlchanges(self, do_exec):
         self._apply_lnd_grid_xmlchanges(do_exec)
         self._apply_ocn_grid_xmlchanges(do_exec)
         self._apply_runoff_ocn_mapping_xmlchanges(do_exec)
-        self._apply_wav_coupling_xmlchanges(do_exec)
 
 
     def _apply_lnd_grid_xmlchanges(self, do_exec):
@@ -642,16 +650,6 @@ def _wav_uses_custom_ocn_grid(self):
         )
         return not picked_standard_wav_grid
 
-    def _apply_wav_coupling_xmlchanges(self, do_exec):
-        """Use the legacy MOM6-WW3 wave coupling method when the custom ocean grid is reused as
-        the wave grid."""
-
-        if cvars["COMP_WAV"].value == "ww3" and self._wav_uses_custom_ocn_grid():
-            with self._out:
-                print(f"{COMMENT}Set wave coupling mode to legacy:{RESET}\n")
-                xmlchange("MOM6_WW3_CPL_METHOD", "legacy", do_exec, self._is_non_local(), self._out)
-
-
     @staticmethod
     def _calc_cores_based_on_grid( num_points, min_points_per_core = 32, max_points_per_core = 300, ideal_multiple_of_cores_used = 128):
         """Calculate the number of cores based on the grid size."""
@@ -946,6 +944,7 @@ def _update_component_grids_xml(
             if self._wav_uses_custom_ocn_grid():
                 comps_sharing_ocn_grid.append("WAV")
             for comp in comps_sharing_ocn_grid:
+                xmlchange(f"{comp}_GRID", ocn_grid, do_exec, self._is_non_local(), self._out)
                 xmlchange(f"{comp}_NX", cvars["OCN_NX"].value, do_exec, self._is_non_local(), self._out)
                 xmlchange(f"{comp}_NY", cvars["OCN_NY"].value, do_exec, self._is_non_local(), self._out)
                 xmlchange(f"{comp}_DOMAIN_MESH", ocn_mesh.as_posix(), do_exec, self._is_non_local(), self._out)
diff --git a/visualCaseGen/custom_widget_types/case_tools.py b/visualCaseGen/custom_widget_types/case_tools.py
index cb5bfdb..b227dcc 100644
--- a/visualCaseGen/custom_widget_types/case_tools.py
+++ b/visualCaseGen/custom_widget_types/case_tools.py
@@ -126,7 +126,7 @@ def xmlchange(var, val, do_exec=True, is_non_local=False, out=None):
 
     out = DummyOutput() if out is None else out
     with out:
-        print(f"{cmd}\n")
+        print(cmd)
 
     if not do_exec:
         return