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

Indian Ocean Dipole outlooks

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

Sea surface temperature (SST) anomalies in the tropical Pacific Ocean are warmer than average along most of the equator in the eastern and central Pacific. Over the past fortnight surface waters have warmed slightly in both the far eastern and central tropical Pacific.

SSTs are also warmer than average across much of the southern Pacific, particularly across areas south of 30°S, extending to waters around southeastern Australia. Overall, SSTs are slightly less warm across the southern Pacific than compared to two weeks ago.

Elsewhere around Australia SSTs are generally close to average.

SSTs for the three NINO regions have warmed slightly compared to two weeks ago. The latest values of the key NINO indices in the tropical Pacific for the week ending 17 February are: NINO3 +0.5 °C, NINO3.4 +0.5 °C and NINO4 +0.8 °C.

Persistent NINO3 or NINO3.4 values warmer than +0.8 °C are typical of El Niño, while persistent values cooler than −0.8 °C typically indicate La Niña.

The El Niño–Southern Oscillation (ENSO) remains neutral. However, the Bureau's ENSO Outlook remains at El Niño WATCH, meaning there is approximately a 50% chance of El Niño developing during the southern hemisphere autumn or winter, twice the normal likelihood.

El Niño typically results in below average autumn and winter rainfall for southern and eastern Australia.

Tropical Pacific sea surface temperatures have warmed slightly in the past fortnight. In the sub-surface, weak warmth extends down to 175 m depth. Recent weakening of the trade winds in the western Pacific means that further warming of the equatorial Pacific is likely in the coming weeks to months.

Five of eight climate models indicate the central Pacific is likely to reach borderline or weak El Niño levels during autumn, with four models remaining above threshold levels into winter. El Niño predictions made in late summer and early autumn tend to have lower accuracy than predictions made at other times of the year. This means that current forecasts of the ENSO state beyond May should be used with some caution.

The Indian Ocean Dipole (IOD) is neutral. The IOD typically has little influence on Australian climate from December to April.

Cloudiness near the Date Line has generally fluctuated around average over the past two to three months, but has tended towards above average since early December. In recent weeks cloudiness near the Date Line has been above average, due to monsoon and tropical cyclone activity within that region.

Equatorial cloudiness near the Date Line typically increases during El Niño (negative OLR anomalies) and decreases during La Niña (positive OLR anomalies).

Trade winds for the 5 days ending 17 February were weaker than average across the western equatorial Pacific, and near average in the east.

Winds were westerly (a reversal of the usual easterlies) over parts of the western Pacific — winds have been westerly over this region for several weeks, and have contributed to renewed warming across the Pacific. The Madden-Julian Oscillation (MJO) is expected to favour strengthening of easterly trade winds in the coming weeks.

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

Five of the eight surveyed climate models predict sea surface temperatures (SSTs) will be at or above El Niño thresholds for March. Four of the models anticipate SSTs will remain above El Niño thresholds until at least July.

Some models indicate a decline in SSTs over autumn and early winter, with some remaining above threshold values despite this decline, while some other models indicate a renewed warming of Pacific surface waters.

It should be noted that model accuracy forecasting through the autumn months is lower than at other times of the year, due to the natural cycle of ENSO, and this may be contributing to the difference in outlooks across the models. Outlooks skill improves for outlooks issued from May.

Sea surface temperatures (SSTs) for January were warmer than average along the equator in the Pacific Ocean, and for a large part of the southern Pacific from around the Date Line in the tropics, to south of 30°S around 120°W. Waters are also warmer than average across southern Australia, across the Tasman Sea and to the east of New Zealand, with waters more than 2 °C warmer than average in parts.

The January values for NINO3 were +0.5 °C, NINO3.4 +0.5 °C, and NINO4 +0.7 °C.

The 30-day Southern Oscillation Index (SOI) has dropped rapidly over the last week, and for the 30 days to 17 February was −5.7. The 90-day SOI was +1.3. Both are within the neutral range.

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

The Indian Ocean Dipole (IOD) is currently neutral. The latest weekly index value to 17 February was −0.28 °C.

Due to the movement of the monsoon trough in the Indian Ocean, the IOD typically has little influence on Australian climate from December to April. When the monsoon trough shifts southwards into the southern hemisphere, it changes the broadscale wind patterns, meaning that the IOD pattern is unable to form.

All of the six international climate models surveyed by the Bureau indicate that the IOD will remain neutral over the coming months, although one model indicates a positive IOD may form by May, with two models predicting a positive IOD during July.

The four-month sequence of sub-surface temperature anomalies (to January) shows warm anomalies across most of the top 200 m of the western half of the equatorial Pacific sub-surface, and cool anomalies in the sub-surface of the eastern half, rising from about 150 m depth in the centre, to just below the surface in the very east of the basin.

Warm anomalies in the sub-surface have decayed over late 2018 and early 2019, although small parts of the sub-surface to the west of the Date Line remain more than two and a half degrees warmer than average.

Temperatures for the five days ending 17 February show warmer than average waters in an area of the central equatorial Pacific between about 75 m and 175 m depth. Warm anomalies in a small part of this region reach between three and four degrees above average, slightly cooler than compared to two weeks ago.

Elsewhere waters are generally close to average temperatures.

Product code: IDCKGEWW00