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

Following links open in new window

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.

Sea surface temperatures (SSTs) in the central tropical Pacific Ocean are within the ENSO-neutral range. Compared to two weeks ago, cool anomalies in the central equatorial Pacific have decreased. Warm anomalies in the western half of the equatorial Pacific have also weakened compared to two weeks ago.

SSTs in the far western Pacific and across South East Asia, including areas around northern Australia, remain warmer than average. Warm anomalies to the northwest of Australia have weakened over the past two weeks.

The Indian Ocean Dipole has returned to neutral levels, after being in a negative phase since May. The tropical Pacific Ocean remains El Niño–Southern Oscillation (ENSO) neutral.

In the tropical Pacific, most indicators of ENSO are well within neutral bounds. In the past fortnight, sea surface temperatures in the central tropical Pacific Ocean have warmed once again, further dampening chances of La Niña. The Southern Oscillation Index (SOI) has been negative since late October (La Niña values are typically positive) but remains neutral. Trade winds are currently close to average. Only cloudiness near the Date Line continues to show some La Niña-like characteristics.

Climate models predict the tropical Pacific Ocean will remain cooler than average, but in the ENSO-neutral range, through until the end of the 2016–17 summer. Only one of the eight models surveyed indicates La Niña for the summer months. A La Niña developing this late in the calendar year has only occurred once since 1980.

The Indian Ocean Dipole (IOD) has returned to neutral levels as the monsoon trough transitions to the southern hemisphere. This shift changes the wind patterns over the tropical Indian Ocean, breaking down the typical IOD circulation. The strong negative IOD event helped drive Australia's wettest May–September period in 117 years of record. The July IOD value was equal-strongest for at least 50 years.

Cloudiness near the Date Line is 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).

For the 5 days ending 20 November trade winds were near average strength across the tropical Pacific Ocean.

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.

Outlooks from the eight international climate models surveyed by the Bureau continue to indicate that neutral ENSO conditions are the most likely outcome for the southern hemisphere summer. One model continues to indicate the likelihood of a brief, late-starting La Niña over the summer. Other models generally indicate neutral conditions for the central Pacific.

A La Niña forming so late in the year has only occurred once since 1980, with the 2008–09 La Niña declared in December 2008.

All models indicate warming of the central Pacific is likely over the coming months.

Weak cool SST anomalies were present along much of the central to eastern equatorial Pacific during October. Warm anomalies were present in the far western Pacific, across most of the southern Pacific outside of the tropics, and across waters around Australia, Indonesia and most of eastern Asia. Large areas adjacent to southeast Australia and between Australia and Indonesia were more than 1 °C warmer than average; these anomalies have eased compared to September.

The October value for the NINO3 region was −0.3 °C, 0.2 °C cooler than for September, while the value for the NINO3.4 region was 0.1 °C cooler at −0.5 °C, and NINO4 was also 0.2 °C cooler −0.2 °C. 

The 30-day Southern Oscillation Index (SOI) to 20 November is −5.8; within the neutral ENSO range. SOI values have been within the neutral range since mid-October following a brief period when they exceeded La Niña thresholds.

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 negative Indian Ocean Dipole (IOD) event has concluded. The weekly index value to 20 November was −0.26 °C. This marks the fourth week the index value has been within neutral values.

IOD events typically decay during spring, and the influence of the IOD on Australian climate is weak during the months December to May. This is because the monsoon trough shifts south over the tropical Indian Ocean changing wind patterns, which prevents the IOD pattern from being able to form.

However, the continued presence of much warmer than average water to the northwest of Australia may see continued influence on Australia, including enhanced rainfall.

The four-month sequence of sub-surface temperature anomalies (to 21 November) shows cooler than average water across the sub-surface of the central to eastern equatorial Pacific Ocean. Compared to October, cool sub-surface anomalies west of the Date Line have weakened and were close to average. Weak warm anomalies persisted in the top 100 m of water west of 160° E; this region has been slightly warmer than average in each month since July.

The sub-surface temperature map for the 5 days ending 20 November shows temperatures close to average across the sub-surface of the equatorial Pacific.

Product code: IDCKGEWW00