by  J. Curry and J. Johnstone, April 9, 2019 in WUWT

CFAN’s 2019 ENSO forecast is for a transition away from El Niño conditions as the summer progresses. The forecast for Sept-Oct-Nov 2019 calls for 60% probability of ENSO neutral conditions, with 40% probability of weak El Niño conditions. – Forecast issued 3/25/19

Introduction

CFAN’s early season ENSO forecast is motivated by preparing our seasonal forecast for Atlantic hurricane activity. ENSO forecasts made in spring have traditionally had very low skill owing to the ENSO ‘spring predictability barrier.’

During fall 2018, there was warming in the Central Equatorial Pacific, leading to a weak El Niño Modoki pattern, which impacted the latter part of the Atlantic hurricane season. This transitioned to a weak (conventional) El Niño in February 2019 and the atmospheric anomalies became more consistent with a conventional El Niño pattern.

NOAA’s latest forecast: Weak El Niño conditions are likely to continue through the Northern Hemisphere spring 2019 (~80% chance) and summer (~60% chance).

CFAN’s ENSO forecast analysis is guided by the ECMWF SEAS5 seasonal forecast system and a newly developed statistical forecast scheme based on global climate dynamics analysis.

ENSO statistics

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Figure 1 illustrates the recent ENSO history as depicted by monthly Niño 3.4 anomalies from 1980 to February 2019.