ENH: Clean up gust time handling for NDBC cwind

This eliminates a warning with Pandas 3.

Author: dopplershift

src/siphon/simplewebservice/ndbc.py

@@ -187,12 +187,11 @@ def _parse_cwind(content):
         df['gust_direction'] = df['gust_direction'].replace(999, np.nan)
         df['wind_gust'] = df['wind_gust'].replace(99.0, np.nan)
         df['time'] = pd.to_datetime(df[['year', 'month', 'day', 'hour', 'minute']], utc=True)
-        df['hours'] = np.floor(df['gust_time'] / 100)
+        df['hours'] = df['gust_time'] // 100
         df['minutes'] = df['gust_time'] - df['hours'] * 100
-        df['hours'] = df['hours'].replace(99, np.nan)
-        df['minutes'] = df['minutes'].replace(99, np.nan)
         df['gust_time'] = pd.to_datetime(df[['year', 'month', 'day', 'hours', 'minutes']],
                                          utc=True)
+        df['gust_time'] = df['gust_time'].where(df['hours'] != 99, pd.NaT)
         df = df.drop(columns=['year', 'month', 'day', 'hour', 'minute',
                               'hours', 'minutes'])
         with warnings.catch_warnings():

tests/test_ndbc.py

@@ -7,6 +7,7 @@
 
 import numpy as np
 from numpy.testing import assert_almost_equal, assert_equal
+import pandas as pd
 import pytest
 
 from siphon.http_util import utc
@@ -93,6 +94,7 @@ def test_ndbc_realtime_cwind():
     assert_almost_equal(df['wind_gust'][0], 9.0, 1)
     assert df['gust_time'][0] == datetime(2018, 8, 1, 14, 49, 0, tzinfo=utc)
     assert df['time'][0] == datetime(2018, 8, 1, 14, 50, 0, tzinfo=utc)
+    assert pd.isna(df['gust_time'][1])
 
     assert df.units['wind_direction'] == 'degrees'
     assert df.units['wind_speed'] == 'meters/second'