ENSO-neutral continued during July, as indicated by near-average sea surface temperatures (SSTs) across the central and eastern equatorial Pacific at the end of the month [Fig. 1]. The latest weekly Niño indices were 0.0°C for the Niño-3 index, +0.1°C for the Niño-3.4 and Niño1+2 indices, and +0.4°C for the Niño-4 index [Fig. 2]. Positive subsurface temperature anomalies (averaged across 180°-100°W) continued over the past month [Fig. 3], and the volume of anomalous warmth extended to the surface in the eastern part of the basin [Fig. 4]. Convection remained suppressed near the Date Line and over western Indonesia [Fig. 5]. Low-level winds were near average across most of the equatorial Pacific Ocean, while upper-level wind anomalies were westerly over the eastern Pacific and near the International Date Line. Overall, the oceanic and atmospheric conditions reflected ENSO-neutral.
The majority of models in the IRI/CPC plume predict ENSO-neutral to continue during the remainder of the Northern Hemisphere summer 2018, with El Niño most likely thereafter [Fig. 6]. Model predictions for El Niño have not wavered despite the recent decrease in the positive SST anomalies in portions of the eastern Pacific. Because of the consistency of forecasts and the expected eventual resurgence in the low-level westerly wind anomalies, the forecasters still favor the onset of El Niño in the coming months. In summary, there is ~60% chance of El Niño in the Northern Hemisphere fall 2018 (September-November), increasing to ~70% during winter 2018-19 (click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).
