diff --git a/docs/sphinx/source/whatsnew/v0.6.0.rst b/docs/sphinx/source/whatsnew/v0.6.0.rst
index 46c939745d..6824952f5b 100644
--- a/docs/sphinx/source/whatsnew/v0.6.0.rst
+++ b/docs/sphinx/source/whatsnew/v0.6.0.rst
@@ -129,6 +129,8 @@ Bug fixes
 * Fix issue with unbounded clearness index calculation in disc. (:issue:`540`)
 * Limit pvwatts_ac results to be greater than or equal to 0. (:issue:`541`)
 * Fix bug in get_relative_airmass(model='youngirvine1967'). (:issue:`545`)
+* Fix bug in variable names returned by forecast.py's HRRR_ESRL model.
+  (:issue:`557`)
 
 
 Documentation
diff --git a/pvlib/forecast.py b/pvlib/forecast.py
index 4e1f7fe751..fcf3952dd9 100644
--- a/pvlib/forecast.py
+++ b/pvlib/forecast.py
@@ -747,8 +747,8 @@ class HRRR_ESRL(ForecastModel):
     """
 
     def __init__(self, set_type='best'):
-        import warnings
-        warnings.warn('HRRR_ESRL is an experimental model and is not always available.')
+        warnings.warn('HRRR_ESRL is an experimental model and is not '
+                      'always available.')
 
         model_type = 'Forecast Model Data'
         model = 'GSD HRRR CONUS 3km surface'
@@ -764,7 +764,7 @@ def __init__(self, set_type='best'):
 
         self.output_variables = [
             'temp_air',
-            'wind_speed'
+            'wind_speed',
             'ghi_raw',
             'ghi',
             'dni',