An example of a prediction:
How does anyone know which way the ENSO behavior is heading if there is not a clear understanding of the underlying mechanism? 
For the prediction quoted above, the closer one gets to an peak or valley, the safer it is to make a dead reckoning guess. For example, I can say a low tide is coming if it is coming off a high tide — even if I have no idea what causes tides.
Yet, if we understand the mechanism behind ocean tides — that it is due to the gravitational pull of the sun and the moon — we can do a much better job of prediction.
The New York Times climate change reporter Justin Gillis suggests that climate science can make predictions as well as geophysicists can predict eclipses:
https://www.nytimes.com/2017/08/18/climate/should-you-trust-climate-science-maybe-the-eclipse-is-a-clue.html. And there is this:
Yet, if climate scientists can't figure out the mechanism behind a behavior such as ENSO, everyone is essentially in the same boat, fishing for a basic understanding.
So what happens if we can formulate the messy ENSO behavior into a basic geophysics problem, something on the complexity of tides? We are nowhere near that according to the current research literature, unless this finding — which has been a frequent topic here — turns out to be true.
In this case, the recent solar eclipse is in fact a clue. The precise orbit of the moon is vital to determining the cycles of ENSO. If this assertion is true, one day we will likely be able to predict when the next El Nino occurs, with the accuracy of predicting the next eclipse.