Climate Model Summary

La Niña likely nearing peak

The weak La Niña that developed at the end of 2017 continues, however most models indicate it may be nearing its peak.This would be consistent wtih the historical timing of the peak in El Niño-Southern Oscillation (ENSO) events, with most reaching their peak strength in December/January before returning to neutral in the autumn months.

While six models maintain La Niña thresholds into February, two suggest a return to neutral values. By April only three models meet the La Niña threshold. This is consistent with earlier outlooks that suggested a weak and short-lived event.

La Niña typically brings above average rainfall to eastern Australia during summer, particularly in northern NSW and Queensland. However, a weak La Niña typically means less influence on Australian rainfall. La Niña events can also increase the likelihood of prolonged warm spells for southeast Australia. 

The Indian Ocean Dipole (IOD) is currently neutral. IOD events are unable to form between December and April due to the seasonal position of the monsoon trough.

NINO3.4 outlook

Weak La Niña conditions persist in the tropical Pacific, with the most recent weekly NINO3.4 value (to 14 January) at −0.7 °C. Most international climate models surveyed by the Bureau suggest this La Niña may be near its peak. Six of eight models maintain values consistent with La Niña in February (of which three only just exceed the threshold) while two models suggest the tropical Pacific will warm back to neutral values. By April, three models just meet the La Niña threshold with the remaining five models returning to neutral conditions.

La Niña is typically associated with above average winter–spring rainfall, particularly over eastern Australia. By summer, the La Niña influence on Australian rainfall weakens in most areas, with the exception of eastern Queensland and northeastern NSW where above average rainfall is typical. However, weak events tend to have less influence on Australian climate patterns. 

The Bureau routinely monitors oceanic and atmospheric conditions and model outlooks. NINO3.4 values that persist below −0.8 °C typically indicate La Niña, while persistent values above +0.8 °C typically indicate El Niño.

Indian Ocean Dipole (IOD) outlook

The IOD is currently neutral with the weekly IOD index value (to 14 January) at −0.3 °C. 

All six models favour a neutral IOD for the rest of 2017 and early 2018.

Indian Ocean Dipole events are typically unable to form between December and April. This is because the monsoon trough shifts south over the tropical Indian Ocean, changing wind patterns which prevents the IOD pattern from being able to form. The IOD has little effect on Australian climate at this time of year.

Predictive Ocean Atmosphere Model for Australia (POAMA)

POAMA, run at the Bureau of Meteorology, generates a nine-month forecast each fortnight. The most recent model run (generated 14 January) indicates NINO3.4 will remain within La Niña levels during the austral summer and close to the La Niña threshold during autumn and early winter, 2018. POAMA maintains La Niña values for longer than most other models - but this period includes the autumn predictability barrier where models typically have less skill.

POAMA's Indian Ocean Dipole (IOD) outlook suggests a neutral IOD is likely during the austral summer and early autumn. The IOD typically has little influence on Australian climate from December to April.

The forecast values, shown below in bold, are POAMA's ensemble mean.

Product code: IDCKGL0000

Australian climate is influenced by 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.

Further details: ENSO Wrap-Up (ENSO and IOD); 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.

More information:

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 POAMA 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.

POAMA Long-Range Outlook

Issued 14 January 2018

Updated fortnightly

These model forecasts of the El Niño – Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) are generated by the Predictive Ocean Atmosphere Model for Australia (POAMA), a dynamical computer model of the climate system run at the Bureau of Meteorology. They are included in the monthly model summary of predictions from POAMA and other models operated by international organisations.

POAMA outlooks provide forecasts out to nine months ahead. The model ensemble distributions shown here provide a range of possible developments in sea surface temperature (SST) in the equatorial Pacific Ocean (NINO regions) and for the Indian Ocean.

NINO34 predictions for the next 9 months.

Skip to past graph to table of values

Outlook graph for selected indice

NINO34 probabilities

Click dates in the first row to see probability graphs
Outlook for month
NINO34 (°C) -0.90 -0.93 -0.83 -0.86 -0.88 -0.85 -0.73
Model cool frequency (<−0.8°C) 87.88% 69.7% 57.58% 57.58% 51.51% 54.55% 45.45%
Model neutral frequency 12.12% 30.3% 42.42% 42.42% 48.48% 45.45% 54.54%
Model warm frequency (>+0.8°C) 0% 0% 0% 0% 0% 0% 0%

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.