Climate Model Summary

Australian climate is influenced by sea surface temperature patterns in the Pacific and Indian oceans. This page provides information on Pacific and Indian ocean outlooks for the coming six months based on a survey of international climate models.

These charts are also available in the Climate Driver Update, along with written details, more charts, and information about other climate drivers.

Further details: Climate Driver Update . Climate Outlooks

Average of international model outlooks for NINO3.4

Average of international model outlooks for the Indian Ocean Dipole (IOD)

Based on the ensemble mean for the most recent model run.

The arrows on the dials indicate the combined average of monthly outlooks from a survey of international global climate models. Note that the individual model runs vary around the average.

 

NINO3.4 covers the central Pacific region.

Graphs

Nino 3.4 2 month outlook Models information
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.


Graphs

Latest IOD outlook Models information
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.


More information:

Sea surface temperature graphs

Australian climate is influenced by sea surface temperature patterns in the Pacific and Indian oceans. Specific regions are monitored, as they can indicate the presence, or potential development, of ENSO (El Niño/La Niña) and Indian Ocean Dipole (IOD) events.

Sea surface temperature graphs

NINO34 predictions for the next 5 months.

Long-range forecast graph for selected SST region

NINO34 probabilities

Product code: IDCK000073

Model details

The models used within our survey are listed below with links to their agency homepages, model output and technical information about the model.

Model data are provided for Bureau of Meteorology use by the agencies detailed in the Models section. Respective agency copyright applies to these data.

Positive IOD continues, but influence likely to weaken in summer

The positive IOD (Indian Ocean Dipole) remains active, and is likely to maintain strong positive IOD index values until at least the end of spring. 

A positive IOD typically means below average winter–spring rainfall for much of southern and central Australia. IOD events are unable to form, and therefore influence Australian climate, during the summer months once the monsoon trough transitions into the southern hemisphere. Therefore, the prolonged dry signal over Australia is likely to weaken during summer.

The El Niño–Southern Oscillation (ENSO) is currently neutral. The latest outlooks from the surveyed models suggest that ENSO-neutral is the most likely scenario for the remainder of 2019 and into 2020.

 

NINO3.4 outlook

The latest weekly NINO3.4 value to 8 September is −0.1 °C, meaning the central tropical Pacific Ocean remains within neutral-ENSO bounds. All eight surveyed models suggest the central tropical Pacific (NINO3.4) is likely to remain neutral with respect to the El Niño–Southern Oscillation (ENSO) from September through to January 2020.

Persistent NINO3.4 values above +0.8 °C typically indicate El Niño, while values below −0.8 °C typically indicate La Niña.

Indian Ocean Dipole (IOD) outlook

Sea surface temperatures in the Indian Ocean have shown patterns consistent with a positive IOD event since the end of May. The IOD index has been above the positive IOD threshold for 7 of the last 8 weeks, with the latest weekly value (to 8 September) well above the threshold at +1.0 °C. This is a result of cooler than average sea surface temperatures off the Java coast and warmer than average temperatures off the Horn of Africa. 

All models suggest positive IOD index values are likely to persist into summer, however, IOD events are unable to form (and therefore influence Australian climate) once the monsoon trough moves into the southern hemisphere, usually from December to April. 

A positive IOD typically means a drier than average winter-spring for parts of southern and central Australia. It also typically means warmer than average winter-spring days for the southern two-thirds of Australia and an early start to the southern bushfire season. Persistent IOD index values above +0.4 °C typically indicate a positive IOD event, while values below −0.4 °C typically indicate a negative IOD event.

Australian Community Climate Earth-System Simulator–Seasonal (ACCESS–S)

The Bureau of Meteorology's climate model generates a six-month forecast for the NINO and IOD indices each fortnight.

The most recent model run (generated 31 August) suggests the central tropical Pacific sea surface temperatures will remain close to average throughout the outlook period, but warm gradually. For the Indian Ocean Dipole (IOD), the Bureau's model suggests positive IOD values are likely to persist throughout  spring, peaking in September and returning to average during the southern summer.

The forecast values, shown below in bold, are for the model's ensemble mean.

Product code: IDCKGL0000

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