Over at Nick Stokes moyhu blog, JCH asserts:
> "The fact is, nobody at this time is reliably forecasting ENSO."
This is how I responded:
To be able to forecast anything, you have to first understand it. Most current weather forecasts are at the level of heuristics. A heuristic doesn't have to be based on science but only on the fact that it has worked sufficiently well in the past. The heuristic is obviously pretty bad for ENSO because the best I have seen works for only a few months in advance. IOW, it's essentially at the level of "slow train coming", to quote Dylan.
That is changing for ENSO as we are developing a much better physical model. [In this blog post](http://contextearth.com/2016/10/24/solver-vs-multiple-linear-regression-for-enso/), I include some ideas from the latest research on wave dynamics.
The central premises to making the model work include:
1. A biennial mode is assumed operating based on the doubling of the annual period.
2. A phase inversion occurs between 1980 and 1996, justified by metastability of the biennial model with respect to even and odd starting years.
3. Mathieu equation formulation for sloshing behavior.
4. A right-hand-side (RHS) forcing due to known angular momentum and gravity terms, with additional seasonal aliasing of the tidal terms.
Given the quality of the results, it won't be long before our understanding of ENSO approaches that of oceanic tides, and we know how well tides can be forecasted. That's essentially predictable for many years in advance, with precision down to the hour. In fact, anything even close to this will be a boon. Take a look at the detail of the fits in the linked post and you can see the potential predictability.