diff --git a/workflow/rocoto/gfs_tasks.py b/workflow/rocoto/gfs_tasks.py
index 55055a46ee..5d52f9463a 100644
--- a/workflow/rocoto/gfs_tasks.py
+++ b/workflow/rocoto/gfs_tasks.py
@@ -110,6 +110,7 @@ def waveinit(self):
 
         resources = self.get_resource('waveinit')
         dependencies = None
+        cycledef = None
         if self.app_config.mode in ['cycled']:
             deps = []
             dep_dict = {'type': 'task', 'name': f'{self.cdump}prep'}
@@ -117,8 +118,9 @@ def waveinit(self):
             dep_dict = {'type': 'cycleexist', 'condition': 'not', 'offset': '-06:00:00'}
             deps.append(rocoto.add_dependency(dep_dict))
             dependencies = rocoto.create_dependency(dep_condition='or', dep=deps)
-
-        task = create_wf_task('waveinit', resources, cdump=self.cdump, envar=self.envars, dependency=dependencies)
+            cycledef = 'gdas_half,gdas' if self.cdump in ['gdas'] else self.cdump
+            
+        task = create_wf_task('waveinit', resources, cdump=self.cdump, envar=self.envars, dependency=dependencies, cycledef=cycledef)
 
         return task
 
@@ -127,10 +129,12 @@ def waveprep(self):
         deps = []
         dep_dict = {'type': 'task', 'name': f'{self.cdump}waveinit'}
         deps.append(rocoto.add_dependency(dep_dict))
+        dep_dict = {'type': 'cycleexist', 'condition': 'not', 'offset': '-06:00:00'}
+        deps.append(rocoto.add_dependency(dep_dict))
         dependencies = rocoto.create_dependency(dep=deps)
-
+        cycledef = 'gdas_half,gdas' if self.cdump in ['gdas'] else self.cdump
         resources = self.get_resource('waveprep')
-        task = create_wf_task('waveprep', resources, cdump=self.cdump, envar=self.envars, dependency=dependencies)
+        task = create_wf_task('waveprep', resources, cdump=self.cdump, envar=self.envars, dependency=dependencies, cycledef=cycledef)
 
         return task