It’s just the latest catch phrase and mumbo jumbo that’s all. A few years ago it was the Asian or Siberian snow index, and before that it was the PDO, and then the QBO, and on and on.
There is never any smoking gun. It’s a myriad of all things, and a give and take between so many of those things…so when people try to attribute just one thing(MJO, PDO, QBO ENSO etc etc..)that drives or affects the total pattern, it’s never gonna work. We honestly just don’t know enough, it’s that simple.
The atmosphere constantly shows us that we are not even close to figuring it out regarding any long range predictions. It’s basically just a guess in the end. Which probably is still a good thing, since there are few mysteries anymore, but this long range weather idea surely still is.