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 remain warmer than average along most of the equator in the eastern and central Pacific, but NINO indices are within the neutral range.

SSTs are also warmer than average across much of the southern Pacific, particularly around the Date Line and across the areas south of 30°S, including waters around the east of Australia and across the Great Australian Bight. SSTs are more than two degrees warmer than average across much of the area between Australia and New Zealand and surrounding Tasmania.

Elsewhere around Australia SSTs are generally close to average.

SSTs for the three NINO regions remain similar to two weeks ago, and are within the ENSO neutral range. The latest values of the key NINO indices in the tropical Pacific for the week ending 3 February are: NINO3 +0.4 °C, NINO3.4 +0.4 °C and NINO4 +0.7 °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) is currently 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.

Tropical Pacific sea surface temperatures have cooled slightly in the past fortnight but remain warmer than average. Importantly, in the central to western Pacific, warmer than average sub-surface waters persist. This is often a precursor to El Niño events. While most atmospheric indicators of ENSO are neutral, trade winds have been weaker than average, or even reversed, across the central and western Pacific in recent weeks, leading to sub-surface warming. Westerly wind anomalies over the western tropical Pacific are forecast to persist a little longer, which is likely to assist further warming of the tropical Pacific.

The majority of climate models suggest ENSO-neutral sea surface temperatures will continue through autumn. However, the current ocean warmth, and the forecast for warmer than average sea surface temperatures later in the year, means the possibility of El Niño remains. Three of eight models suggest that El Niño may establish by mid-2019, with another three models on the warm side of neutral. 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.

El Niño often, but not always, brings below average autumn and winter rainfall to southern and eastern Australia.

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 more time above average during early December to late January. It would typically be well above average during El Niño.

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

Trade winds were for the 5 days ending 3 February were stronger 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. Model outlooks indicates westerly anomalies will persist for some time, which may lead to renewed warming across the Pacific.

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.

Three of the eight surveyed climate models predict sea surface temperatures (SSTs) will be above El Niño thresholds during February, while the rest indicate warm but ENSO-neutral SSTs.

Outlooks remain mixed during the southern hemisphere autumn to winter. It should be noted that model accuracy forecasting through the autumn months is lower than at other times of the year, and this may explain the wider-than-usual spread in model outlooks for the coming months.

Some models anticipate a continued decline in SSTs over autumn and early winter, however three of the eight models predict SSTs will be above El Niño thresholds in June, with another three on the warm side of neutral.

 

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) to 3 February was +0.7, and the 90-day SOI was +3.8; both well 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 3 February was −0.23 °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 through autumn 2019.

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 3 February show warmer than average waters in an area of the central equatorial Pacific between about 100 m and 200 m depth. Warm anomalies in a small part of this region reach more than four degrees above average.

Elsewhere waters are generally close to average temperatures.

Product code: IDCKGEWW00