That is truly an ancient script by Michael of the former relayweather.. the last version I have was from 2011.
I think the issue is your quality data page from gladstone has a missing icon for a check mark about wind data and that causes the script to emit the Notice errata.
You can change cwopstats.php to have
<?php
error_reporting(E_ALL & ~E_NOTICE);
at the top of of the page (replacing the opening <?php