Monday 23 May 2022

Tropical Pacific warmer than average, but ENSO neutral to stay for 2017

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MELBOURNE, Australia – The El Niño-Southern Oscillation (ENSO) remains neutral. All climate models surveyed by the Bureau indicate the tropical Pacific Ocean is likely to stay ENSO neutral for the rest of 2017.

Sea surface temperatures (SSTs) in the central tropical Pacific (the NINO3.4 region) have been warmer than average, though still in the neutral range, since mid-April.

The current NINO3.4 value of +0.5 °C is the result of a localised warm anomaly. The overall sea surface temperature pattern is inconsistent with a developing El Niño, meaning further ocean warming and El Niño development remains unlikely.

This is reflected in neutral ENSO outlooks from all international climate models surveyed. Other indicators of ENSO, such as the Southern Oscillation Index, cloudiness near the Date Line, and trade winds also remain at neutral levels.

The Indian Ocean Dipole (IOD) is neutral. However, two of six climate models suggest positive IOD thresholds could be reached in the coming months.

Only one of these models suggests these will last long enough to be considered a positive IOD event.

Positive IOD events are typically associated with below average winter and spring rainfall over central and southern Australia.

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