Complex sentence: CBS pulled the third season finale, titled "Windy City", from its May 20,2013 showing, due to the show featuring a tornado descending on Chicago, which was the same day of the 2013 Moore tornado.
Split into simpler sentences: CBS pulled the third season finale, titled "Windy City", from its May 20,2013 showing. The episode featured a tornado descending on Chicago, and would have been broadcast the same day as the 2013 Moore tornado.