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.

The surface of the ocean remained weakly warmer than average along much of the equatorial Pacific Ocean for the week ending 5 January, with some slight warming over the past fortnight. However, overall, patterns remain consistent with a neutral ENSO state.

The surface of the ocean around most of Australia has also remained warmer than average, and more than 2 °C warmer than average off northwest Australia, with the Queensland coastline close to average.

The Indian Ocean has seen steady warming in the eastern tropical Indian Ocean, with the basin now warmer than average across most of the tropics. This is consistent with the Indian Ocean Dipole's return to neutral.

The latest values of the three key NINO indices in the tropical Pacific for the week ending 22 December were: NINO3 +0.2 °C, NINO3.4 +0.4 °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 Indian Ocean Dipole (IOD) has returned to neutral after one of the strongest positive IOD events to impact Australia in recent history. The IOD is expected to remain neutral in the coming months, meaning that it will have little influence on Australian and global climate.

However, the IOD’s legacy of widespread warm and dry conditions during the second half of 2019 primed the Australian landscape for bushfire weather and heatwaves this summer.

In the Pacific Ocean, although indicators of the El Niño–Southern Oscillation (ENSO) are neutral, the tropical ocean near and to the west of the Date Line remains warmer than average, potentially drawing some moisture away from Australia.

Most climate models indicate ENSO will remain neutral until at least the end of the southern hemisphere autumn, meaning it will have limited influence on Australian and global climate.

When the IOD and ENSO are neutral, Australia’s climate can be influenced by more local or short-term climate drivers. The Bureau's Climate Outlook for the weeks, months and seasons ahead include all the climate influences on Australian weather.

Cloudiness near the Date Line has been above average in the second half of December and early January, after having generally remained below average since early to mid-September. Overall cloud patterns are consistent with neutral ENSO.

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 5 January are mostly close to average across the tropical Pacific, but some small pockets in the west and east are slightly weaker than average. Trade winds have been mostly close to average over the past six months, with weakened trade winds confined to the far west of the tropical 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.

Most international climate models indicate central tropical Pacific sea surface temperatures in the NINO3.4 region will remain at ENSO-neutral levels through the southern hemisphere autumn 2020. One model of eight approaches El Niño thresholds at times, while another exceeds La Niña thresholds in late autumn.

The surface of the ocean remained warmer than average across much of the western equatorial Pacific Ocean during December, and in a thin band along the equator in the east.

The surface of the ocean was also warmer than average around much of the north, west, and south of Australia during December, and near average to the east.

The December values for NINO3 were +0.4 °C, NINO3.4 +0.4 °C, and NINO4 +0.8 °C. All three NINO indices cooled compared to November. 

The 30-day Southern Oscillation Index (SOI) for the 30 days ending 5 January is −5.7. The 90-day value is also −5.7. The 30-day SOI values have generally remained within neutral bounds over the past month.

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) has returned to neutral, indicating the end of the strong positive IOD event that peaked in October 2019. The past two weeks have seen the index below positive IOD thresholds (+0.4 °C), with the latest weekly value to 5 January +0.2 °C.

The temperature gradient across the Indian Ocean has reduced significantly over the past two months. Surface waters in the west of the basin have remained broadly warmer than average, while in the east of the basin surface waters warmed over the past two months. The overall pattern of sea surface temperatures was generally consistent with a positive IOD pattern from late May to late December.

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. This year the positive IOD event decayed much slower than usual, persisting through to late December, as the monsoon trough took longer to move into the southern hemisphere than it usually does.

The four-month sequence of equatorial sub-surface temperature anomalies (to December) shows the top 150 m of the western to central equatorial Pacific is warmer than average, with cooler than average waters at a depth of around 50 to 200 m in the east. Small volumes of water reach more than 2 degrees warmer/cooler than average in each region respectively.

The pattern has remained somewhat similar over the past three months, with mostly weak to moderate temperature anomalies. The area of cool anomalies below the surface has migrated eastward over those three months.

For the five days ending 5 January, the sub-surface of the ocean was close to average temperature along the equator. A small band of warmer than average water extends from the Date Line at 150 m depth, across to the shallow eastern Pacific, with the warmest anomalies more than 3 °C warmer than average near the Date Line. A weak pool of cooler water sits around 100 to 200 m depth in the far west.

Product code: IDCKGEWW00

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