Climate Model Summary

Models indicate potential for late-forming La Niña

Sea surface temperatures in the tropical Pacific remain within the neutral ENSO range. Model outlooks for the next six months are mixed, with a number suggesting La Niña may develop during the austral spring or summer.

Five models indicate that La Niña thresholds will be met at some point during the spring or summer, with only three of these indicating an event that will persist for some time. No models are forecasting a strong event. Summer would be considered very late, although not unprecedented, for La Niña to develop.

Impacts on Australian climate have been observed in both near-miss and late-forming La Niña events.

All surveyed models are in agreement that the current negative Indian Ocean Dipole (IOD) is likely to decline during spring, with a return to neutral conditions by November.

 

NINO3.4 outlook

The latest NINO3.4 outlooks (initialised in August) are mixed, with significant variation between models and a generally wide spread in ensemble members within each model. Three models, including the Bureau's model, suggest some initial cooling in central tropical Pacific sea surface temperatures before warming again later in 2016. Others indicate a persistent cooling throughout spring and summer, exceeding La Niña thresholds by January. The Bureau's model, ECMWF and NASA models indicate neutral conditions to persist throughout the forecast period.

The all-model average NINO3.4 outlook for each month between September and the end of the year is between −0.4 °C and −0.6 °C, so remaining on the cool side of neutral, but not exceeding the La Niña threshold.

The Bureau routinely monitors oceanic and atmospheric conditions and model outlooks. The most recent weekly NINO3.4 value to 14 August is −0.4 °C. NINO3.4 values below −0.8 °C typically indicate La Niña events.

Indian Ocean Dipole (IOD) outlook

The latest weekly IOD index value to 14 August is −0.5 °C, having weakened significantly in recent weeks from a peak value of −1.4 °C in early July. The IOD index has been at or below the −0.4 °C threshold value for 12 consecutive weeks now.

Model outlooks surveyed by the Bureau of Meteorology suggest the IOD is likely to return to neutral values by the end of spring - consistent with the typical IOD event lifecycle. This is a month earlier than forecasts issued in previous months indicated. A negative IOD typically enhances rainfall over southern Australia during winter and spring. For more information on the establishment of the negative IOD in 2016, see the ENSO Wrap-Up.

Predictive Ocean Atmosphere Model for Australia (POAMA)

POAMA, run at the Bureau of Meteorology, generates an eight-month forecast each fortnight. The most recent model run (generated 14 August) suggests NINO3.4 will come close to La Niña thresholds (−0.8 °C) in September but return to more neutral values soon after. POAMA suggests values will remain on the cool side of neutral from October until the end of summer 2016-17. The forecast values, shown below in bold, are for 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 August 2016

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) -0.63 -0.48 -0.37 -0.40 -0.44 -0.41 -0.27
Model cool frequency (<−0.8°C) 6.06% 6.06% 3.03% 3.03% 12.12% 15.15% 9.09%
Model neutral frequency 93.94% 93.94% 96.97% 96.97% 87.88% 84.84% 90.9%
Model warm frequency (>+0.8°C) 0% 0% 0% 0% 0% 0% 0%

More information:

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.