Climate Driver Update Archive
Climate drivers in the Pacific, Indian and Southern oceans and the Tropics


Average of international model outlooks for NINO3.4

Average of international model outlooks for IOD


Sea surface temperature maps

Sea surface temperature maps are not available for forecasts before Spring 2018

Global sea surface temperature outlooks for the months and season ahead. Anomalies indicate the difference from normal.

Sea surface temperature maps (select map for larger view)

SST outlooks for the next 3 months

Pacific Ocean

ENSO is the oscillation between El Niño and La Niña states in the Pacific region. El Niños typically produce drier seasons, and La Niñas drive wetter years, but the influence of each event varies, particularly in conjunction with other climate influences.

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.

International climate model outlooks

Nino 3.4 2 month outlook
Graph details

The graphs are based on the ensemble mean for the most recent model run.

These graphs show the average forecast value of NINO3.4 for each international model surveyed for the selected calendar month. If the bars on the graph are approaching or exceeding the blue dashed line, there is an increased risk of La Niña. Similarly, if the bars on the graph are approaching or exceeding the red dashed line, there is an increased chance of El Niño.

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

The Indian Ocean Dipole (IOD) compares sea surface temperatures. An IOD negative state, having warmer than average sea surface temperatures near Australia, provides more moisture for frontal systems and lows crossing Australia.

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.

International models

Latest IOD outlook
Graph details

The graphs are based on the ensemble mean for the most recent model run.

Thse graphs show the average forecast value of the IOD index for each international model surveyed for the selected calendar month. If the majority of models are approaching or exceeding the blue dashed line, then there is an increased risk of a negative IOD event. If the majority of models are approaching or exceeding the red dashed line, then there is an increased risk of a positive IOD event.

The Southern Annular Mode, or SAM, refers to the north-south shift of rain-bearing westerly winds and weather systems in the Southern Ocean compared to the usual position.

The Madden-Julian Oscillation (MJO) is the major fluctuation in tropical weather on weekly to monthly timescales. It can be characterised as an eastward moving 'pulse' of cloud and rainfall near the equator that typically recurs every 30 to 60 days.

Sea surface temperature (SST) anomalies for the week ending 12 May were warmer than average across nearly the entire tropical Pacific Ocean. Compared to two weeks ago, the surface of the ocean has warmed slightly in the west and cooled slightly in the east — a weakening of the typical El Niño pattern. Most of the tropical Pacific region is half to one degree warmer than average.

Waters are also warmer than average across much of the southern Pacific Ocean, particularly across areas south of 30°S. SSTs are up to two degrees warmer than average over a broad area extending across the Tasman Sea, along the New South Wales coast, and well to the east of New Zealand. Waters around the rest of Australia are generally close to average temperatures, although weak cool anomalies are present to the southwest of Australia and in the west of the Great Australian Bight.

The latest values of the three key NINO indices in the tropical Pacific for the week ending 12 May are: NINO3 +0.7 °C, NINO3.4 +0.7 °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.

Indicators have been close to El Niño thresholds over the past several months, but signs have emerged of a weakening of these patterns. As a result, the Bureau's ENSO Outlook has been downgraded to El Niño WATCH. This means the chance of El Niño developing in 2019 is approximately 50%, which is still double the normal likelihood.

While sea surface temperatures in the tropical Pacific Ocean remain close to El Niño levels, water beneath the surface has slowly cooled over the past few months. Atmospheric indicators such as the Southern Oscillation Index (SOI) and cloudiness near the Date Line have generally remained in the neutral range, despite short-term El Niño-like SOI values in the last fortnight.

International models surveyed by the Bureau indicate that sea surface temperatures in the tropical Pacific are likely to remain near El Niño thresholds until mid-winter, before cooling in late winter to spring. By August, two of the eight models are clearly at El Niño levels, with another two near El Niño thresholds.

El Niño typically brings drier than average conditions for eastern Australia during winter–spring, and warmer days across the southern two-thirds of the country.

The Indian Ocean Dipole (IOD) is currently neutral. However, models show a tendency towards positive IOD values during the forecast period, with five of six models suggesting a positive IOD event is likely to develop in winter, and persist into mid-spring.

Cloudiness near the Date Line has been generally above average since early December, however, values have fluctuated closer to average since late April.

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 12 May are close to average to the west of the Date Line. The weakened trade winds in the western Pacific are likely tied in with the current passage of the Madden-Julian Oscillation, and could temporarily warm parts of the tropical Pacific Ocean again. 

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.

While most climate models forecast El Niño-like warmth to persist the early austral winter, the ocean is forecast to cool over late winter and spring.

While seven of eight surveyed climate models anticipate El Niño thresholds will be met for June, for August and September two models remain in El Niño territory and two are at borderline values, with the remaining four models indicating neutral conditions are most likely.

Note that model accuracy when forecasting through the autumn months is lower than at other times of the year, due to the natural cycle of ENSO. Forecast accuracy improves for outlooks issued in June.

Sea surface temperatures (SSTs) for April were warmer than average across most of the tropical Pacific Ocean. Temperature anomalies in many areas had decreased slightly compared to March.

A significant area of warmer than average SSTs were present surrounding southeast Australia, extending across the Tasman Sea and well to the east of New Zealand; temperatures were up to two degrees warmer than average in much of this region. Waters were also warmer than average in coastal waters of much of the Great Australian Bight, while areas of cool anomalies were present to the southwest of Australia.

The March values for NINO3 were +0.7 °C, NINO3.4 +0.7 °C, and NINO4 +0.6 °C, with values for both the central and western regions cooler than for March.

The 30-day Southern Oscillation Index (SOI) remains neutral. The SOI value for the 30 days to 12 May was −6.2, while the 90-day average was −8.3.

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 12 May is +0.06 °C.

All six of the international climate models surveyed by the Bureau indicate that the IOD will be positive for June. For July, one model drops back to neutral, but the other five models forecast positive IOD values to persist through to at least the end of the outlook period (October).

A positive IOD often results in below average winter–spring rainfall over southern and central Australia.

The four-month sequence of equatorial sub-surface temperature anomalies (to April) shows that although the sub-surface of the tropical Pacific has continued to cool, weak positive anomalies persist across most of the top 100 m of the sub-surface. Below 100 m depth, cool anomalies have strengthened, and some parts of the sub-surface are up to three degrees cooler than average.

Temperatures for the five days ending 12 May show waters were warmer than average in the shallow sub-surface of the eastern equatorial Pacific, with waters in much of the top 50 m east of 130°W more than two degrees warmer than average. Compared to two weeks ago, warm anomalies in this area have reduced.

Elsewhere temperatures were close to average, although there are some small pockets of cool anomalies more than two degrees cooler than average in the deeper sub-surface in the east, and at around 200 m depth near the Date Line.

Product code: IDCKGEWW00

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