diff --git a/ww3/update_noaa_ww3_forecasts.py b/ww3/update_noaa_ww3_forecasts.py
index f35b98d..95938f6 100644
--- a/ww3/update_noaa_ww3_forecasts.py
+++ b/ww3/update_noaa_ww3_forecasts.py
@@ -26,7 +26,8 @@ def get_ww3_forecast(lon, lat, var_names, t):
         t (datetime): timezone-aware local datetime.
 
     Returns:
-        time series dataframe.
+        df (dataframe):  forecast time series of selected variables.
+        filename (str):  name of forecast file (e.g. 'nww320191212_18z').
 
 
     Available variables: