SFGate reports ?Supernatural? is finally scheduled to come to an end with its fifteenth season. The final year of the beloved CW drama will consist of 20 episodes. Star Jared Padalecki announced the news via Twitter on Friday, writing: ?Hey #SPNFamily here?s a little message from @JensenAckles @mishacollins and me. I?m so grateful for the family that?s been built because of the show. Excuse me while i go cry.? ?Supernatural? is the longest-running sci-fi/genre series in the history of American broadcast television and will have a total of 327 episodes by its end. The series began on the WB Network on Sept. 13, 2005.