Climate Model Summary

Negative IOD, but ENSO remains neutral

The El Niño-Southern Oscillation (ENSO) remains neutral. Most international models surveyed by the Bureau of Meteorology suggest that neutral ENSO conditions are likely to continue, however the Bureau of Meteorology's model suggests there is an increased chance of weak La Niña conditions forming during the winter months.

The Indian Ocean Dipole (IOD) is currently negative. All five international models surveyed suggest this negative event is likely to persist throughout the southern winter and into spring. A negative IOD event during winter-spring increases the chances of above normal rainfall over southern Australia.

For more details on both ENSO and the IOD, please see the ENSO Wrap-Up.

Average of international model outlooks for NINO3.4

Graphs representing the description above.

The arrows on the dials above indicate the combined average of monthly NINO3.4 outlooks from a survey of international global climate models. Note that the individual model runs vary around the average.

NINO3.4 Outlook

The NINO3.4 consensus outlook indicates neutral ENSO conditions (neither El Niño nor La Niña) are likely to persist. However, the latest forecasts (initialised in June) from the surveyed international models show some divergence, with the Bureau's model (POAMA) favouring weak La Niña conditions to develop during the winter months before returning to neutral values later in the year. The most recent NINO3.4 value is 0.0°C for the week ending 16 Jun 2013.

The following graph shows 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.

NINO3.4 covers the central Pacific region.

NINO3.4 Outlook

These form controls display per month outlook graphs.

Month 2 Month 4 Month 6

Indian Ocean Dipole (IOD)

The IOD index is currently negative, with a value of -0.5°C for the week ending 16 June 2013. The IOD consensus outlook indicates that this negative event will continue throughout winter and into spring with all five models predicting values to still be exceeding the negative IOD threshold in September.

The following graph shows 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.

Predictive Ocean Atmosphere Model for Australia (POAMA)

POAMA, run at the Bureau of Meteorology, generates an eight-monthly forecast on the first day of each month. The most recent model run (started in June) predicts NINO3.4 is likely to cool during winter, dropping just below La Niña thresholds. Neutral values are forecast to return later in the year. The following forecast values are for the ensemble mean.

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.

Agency/Source/Provider	Latest NINO3.4	Latest IOD	Model	Model run used in this survey:
BOM - Bureau of Meteorology	View NINO3.4 data	View IOD data	POAMA	Unavailable
ECMWF (EU)	View NINO3.4 data	Not public	System4	Unavailable
JMA	View NINO3.4 data	Unavailable	JMA/MRI-CGCM	Unavailable
METEO-FRANCE	Not public	Not public	ARPEGE	1 April 2013
NASA - GMAO (USA)	View NINO3.4 data	View IOD data	GEOS5	1 April 2013
NOAA - NCEP (USA)	View NINO3.4 data	Unavailable	CFSv2	Unavailable
UKMO	View NINO3.4 data	Not public	GloSea4	Unavailable