ENSO Wrap-Up
Current state of the Pacific and Indian oceans

Weekly sea surface temperatures

Graphs of the table values

Monthly sea surface temperatures

Graphs of the table values

5-day sub-surface temperatures

Monthly temperatures

Southern Oscillation Index

30-day SOI values for the past two years
Select to see full-size map of 30-day Southern Oscillation Index values for the past two years, updated daily.

Trade winds

5-day SST and wind anomaly from TAO/TRITON
Select to see full-size map of 5-day SST and wind anomaly from TAO/TRITON.

Cloudiness near the Date Line

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ENSO outlooks

NINO3.4 SST plumes from POAMA forecasts, updated daily
Select to see full-size map of NINIO3.4 SST plumes from POAMA forecasts, updated daily.

Indian Ocean Dipole outlooks

IOD SST plumes from POAMA forecasts, updated daily
Select to see full-size map of IOD SST plumes from POAMA forecasts, updated daily.

For the week ending 15 January 2017, sea surface temperatures (SSTs) in the equatorial Pacific Ocean are close to average, clearly within the ENSO-neutral range. Over the past fortnight, warm anomalies across the Pacific south of the equator have strengthened. Warm sea surface temperature anomalies to the southeast of Australia have also increased.

In the tropical Pacific Ocean, the El Niño–Southern Oscillation (ENSO) remains neutral. A neutral ENSO period indicates that the tropical Pacific Ocean is not shifting the odds towards a significantly wetter or drier period for Australia. When ENSO is in a neutral phase weather extremes can and do occur due to the influence of secondary or local factors.

Most indicators of ENSO, such as sea surface temperatures, the 90-day Southern Oscillation Index (SOI) and the trade winds are within the ENSO-neutral range. However, cloudiness near the Date Line continues to show a weak La Niña-like pattern.

All climate models indicate that the Pacific Ocean is likely to remain ENSO neutral through the southern summer and autumn. Model outlooks that span the autumn period tend to have lower skill than outlooks made at other times of the year, therefore outlooks beyond May should be used with caution.

The Indian Ocean Dipole has little influence on Australian climate during the months from December to April.

Cloudiness near the Date Line remains below average, and has been generally below average since the start of August.

Equatorial cloudiness near the Date Line typically increases during El Niño (below average OLR) and decreases during La Niña (above average OLR).

Trade winds for the 5 days ending 15 January 2017 were stronger than average over the equatorial Pacific to the west of the International Date Line, and near average over the eastern half of the tropical Pacific. Trade winds have been generally close to average since autumn 2016.

During La Niña events, there is a sustained strengthening of the trade winds across much of the tropical Pacific, while during El Niño events there is a sustained weakening, or even reversal, of the trade winds.

Climate models surveyed by the Bureau indicate that neutral ENSO conditions are likely for the remainder of the southern hemisphere summer and into autumn. All models indicate the central Pacific is likely to warm over the coming months.

Three models suggest strong warming may be possible in autumn, with two reaching El Niño thresholds by either May or June. It must be noted that this outlook straddles the autumn predictability barrier—typically the ENSO transition period—during which most models have their lowest forecast accuracy.

SST anomalies for December show the equatorial Pacific Ocean is close to average (within 0.5 °C of the long-term average). Only a few small areas remain cooler than −0.5 °C. A band of weakly warmer-than-average water persists in the southwest Pacific, close to the South Pacific Convergence Zone (SPCZ).

Warmer waters persist in the far western equatorial Pacific, but have cooled over the past few months. Only a small area off the northwest coast of Australia is more than +1 °C warmer than average, and also an area to the east of the Asian continent. Waters off the east coast of southeast Australia also remain warmer than average.

The December values for the NINO3, NINO3.4 and NINO4 regions were −0.3 °C, −0.3 °C and 0 °C, respectively.

The 30-day Southern Oscillation Index (SOI) to 15 January 2017 is +7.6 (90 day value +1.9). SOI values have been within the neutral range since mid-October.

Sustained positive values of the SOI above +7 typically indicate La Niña while sustained negative values below −7 typically indicate El Niño. Values between about +7 and −7 generally indicate neutral conditions.

The Indian Ocean Dipole (IOD) is neutral. The weekly index value to 15 January is −0.21 °C.

The influence of the IOD on Australian climate is weak during December to April. This is due to the monsoon trough shifting south over the tropical Indian Ocean and changing the overall wind circulation, which in turn prevents an IOD ocean temperature pattern from being able to form. Current outlooks suggest a neutral IOD for the end of autumn.

The four-month sequence of sub-surface temperature anomalies (to December) shows cooler than average water across the sub-surface of the central to eastern equatorial Pacific Ocean. This cooler water has been progressively warming and shrinking in volume since September.

Weak warm anomalies have persisted in the top 100 metres of the tropical Pacific in areas west of the Date Line. December saw an increase in intensity of these weak warm anomalies, which are now approximately +2 °C.

The sub-surface temperature map for the 5 days ending 15 January 2017 shows waters are close to average across the sub-surface of the equatorial Pacific.

Product code: IDCKGEWW00