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 26 March, sea surface temperatures (SSTs) in the central equatorial Pacific Ocean were close to average. Warm anomalies were present in the far western Pacific, and in the eastern Pacific. Anomalies in the far eastern Pacific reach more than +1 °C, and more than +2 °C in a small area near the South American coast.

Warm SST anomalies also persist around eastern Australia, and across much of the Pacific south of the equator.

The NINO 3 and 3.4 regions both warmed by 0.1 °C over the past fortnight. The NINO3 SST anomaly for the week ending 12 March was +0.5 °C, NINO3.4 +0.2 °C and NINO4 −0.1 °C.

The El Niño–Southern Oscillation (ENSO) remains neutral. However, the Bureau's ENSO Outlook status is at El Niño WATCH, indicating around a 50% chance of El Niño developing in 2017.

Sea surface temperatures (SSTs) in the central and eastern tropical Pacific Ocean have steadily warmed since the start of the year. In waters near the South American coastline, some areas are now at least 3 °C above average. However, all indicators of ENSO remain within neutral levels. In the atmosphere, recent fluctuations in the Southern Oscillation Index (SOI) can be attributed to movements in the monsoon trough associated with severe tropical cyclone Debbie, and are not indicative of ENSO.

All international models surveyed by the Bureau suggest that the current steady warming of the tropical Pacific Ocean is likely to continue in the coming months. Seven of eight models indicate that sea surface temperatures will exceed El Niño thresholds during the second half of 2017. However, some caution must be exercised as models have lower accuracy at this time of year.

El Niño is often, but not always, associated with below average winter–spring rainfall over eastern Australia and warmer than average winter–spring maximum temperatures over the southern half of Australia.

The Indian Ocean Dipole (IOD) has little influence on Australia from December to April. Current outlooks suggest a neutral IOD is likely to remain at least through to the end of winter.

Cloudiness remains below average near the Date Line. Cloudiness has been generally below average since the start of August 2016.

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 26 March were stronger than average over some parts of the western tropical Pacific, and near average of the eastern Pacific. Trade winds have been stronger than average over the western tropical Pacific for around one month.

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 the central Pacific will continue to warm, with a few models indicating El Niño may emerge by the end of autumn. All models but one indicate El Niño thresholds will be reached during winter 2017.

However, it should be noted that model outlooks that span the southern autumn period tend to have lower accuracy than outlooks issued at other times of the year. This means outlooks beyond May should be used with some caution.

SST anomalies for February show the equatorial Pacific Ocean is close to average. Warm anomalies were present in the far eastern Pacific, across much of the Pacific south of the equator, and in the far western Pacific around eastern Australia and much of the Maritime Continent.

The February values for the NINO3, NINO3.4 and NINO4 regions were +0.5 °C, 0.0 ° and −0.1 °, respectively.

The 30-day Southern Oscillation Index (SOI) to 26 March is +5.6 (90-day value +2.1). SOI values have generally 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 26 March was +0.19 °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 23 March) shows cooler than average water across the sub-surface of the central to eastern equatorial Pacific Ocean. These cool anomalies are similar in strength to those observed for February, but have generally been weakening and decreasing in volume since September.

Areas of weak warm anomalies are present in the top 100 to 150 m of the tropical Pacific west of the Date Line, and also remain similar to February in strength, but have contracted slightly westward.

The sub-surface temperature map for the 5 days ending 26 March shows waters are generally close to average across the sub-surface of the equatorial Pacific Ocean.

Product code: IDCKGEWW00