diff --git a/ush/HWP_tools.py b/ush/HWP_tools.py
index 3fdc1b662..21bedc720 100755
--- a/ush/HWP_tools.py
+++ b/ush/HWP_tools.py
@@ -18,7 +18,7 @@ def check_restart_files(hourly_hwpdir, fcst_dates):
          hourly_hwpdir: the directory where the RESTART data is copied (nwges/HOURLY_HWP)
          fcst_dates: Forecast dates
     Returns:
-         list of hwp_avail_hours, hwp_non_avail_hours
+         lists of hours with and without available RESTART files
     """
     hwp_avail_hours = []
     hwp_non_avail_hours = []
@@ -40,6 +40,11 @@ def check_restart_files(hourly_hwpdir, fcst_dates):
 def copy_missing_restart(nwges_dir, hwp_non_avail_hours, hourly_hwpdir):
     """Check the restart files.
 
+    The script loops through hwp_non_avail_hours (missing files in
+    nwges/HOURLY_HWP) and determines if an alternative RESTART file in
+    nwges/fcst_fv3lam/RESTART is available instead. If so, it is
+    appended to restart_avail_hours.
+
     Args:
          nwges_dir: holds the boundary, INPUT, and RESTART files (e.g,
          described here:
@@ -51,7 +56,9 @@ def copy_missing_restart(nwges_dir, hwp_non_avail_hours, hourly_hwpdir):
          hwp_non_avail_hours: a list of hours without available RESTART files
          hourly_hwpdir: the directory where the RESTART data is copied (nwges/HOURLY_HWP)
     Returns:
-         list of (restart_avail_hours, restart_nonavail_hours_test)
+         list of::
+         - restart_avail_hours
+         - restart_nonavail_hours_test which is a subset of hwp_non_avail_hours.
 
     """
     restart_avail_hours = []
@@ -118,7 +125,11 @@ def process_hwp(fcst_dates, hourly_hwpdir, cols, rows, intp_dir, rave_to_intp):
          intp_dir: the working directory for smoke processing (${CYCLE_DIR}/process_smoke)
          rave_to_intp: a string based on the grid name:: rave_to_intp = predef_grid+"intp"
     Returns:
-         list of (hwp_ave_arr, xarr_hwp, totprcp_ave_arr, xarr_totprcp)
+         list of::
+         - average (through time) of HWP_AVE in the available RESTART files
+         - hwp_ave_arr converted to an xarray DataArray
+         - the total precipitation vector (totprcp) reshaped to the 2D grid
+         - totprcp_ave_arr converted to an xarray DataArray
     """
     hwp_ave = [] 
     totprcp = np.zeros((cols*rows))