I wonder if the Tip theory is the whole issue? Basically calling enso based on SSTAs which may be in part overall warming induced making El Niño less predictable. Conversely, perhaps on that basis the current nina is stronger than we think. But the big problem is the sample size is so small vs real science (eg: population studies in medical research could have an n of 30,000 vs the long range forecasting which is under 50 making it not really scientifically valid imho.