Good article. Perhaps you failed to say, that now we are in a cold phase PDO, and that will probably last till 2025-2030, we have the warm phase 1978-1999/2000, and before that, its cold phase during 1947-1977 approximately. During cold phase El Niño is less frequent and intense than during warm PDO. Also as I have said before, this index is not generally taken into account in modelling El Niño. It seems that El Niño in 1-2 does not develop much during cold phases (2015-2016). Check out California impacts of El Niño during cold phase PDO.