How well did we predict the 2014 and 2015 Evolution of El Niño?

Abstract:

Here, we will examine the official ENSO outlooks, along with a suite of statistical and dynamical prediction models, and discuss how they have fared over the past couple of years. After predictions of El Niño’s emergence in 2014, sea surface temperature (SST) anomalies across the equatorial Pacific were near El Niño thresholds through the winter of 2014-15. However, due to the lack of a clear atmospheric response, it wasn’t until March 2015 that ENSO forecasters declared the onset of El Niño. As of early August 2015, the Niño-3.4 SST index has reached levels that are within the top 5% of its distribution, along with atmospheric features consistent with ocean-atmosphere coupling. Multi-model ensemble mean forecasts are unanimous in predicting a strong event in the second half of 2015 (3-month average value in Niño-3.4 SST at or exceeding 1.5C).