Climate Model Summary

Climate Model Summary Archive: December 2013

Neutral ENSO through summer

The El Niño-Southern Oscillation (ENSO) remains neutral. All of the international climate models surveyed by the Bureau of Meteorology indicate the tropical Pacific is most likely to remain neutral at least through to the austral autumn.

The Indian Ocean Dipole (IOD) is also neutral. The IOD typically has little impact upon Australian climate throughout the months from December to April.

NINO3.4 Outlook

The latest NINO3.4 forecasts (initialised in December) from all available models indicate the El Niño-Southern Oscillation (ENSO) is likely to remain neutral through to the austral autumn 2014. A number of models show some weak warming, but remain well within the neutral bounds. The most recent NINO3.4 value is +0.1 °C for the week ending 15 December 2013.

Indian Ocean Dipole (IOD)

The IOD index remains neutral with a latest weekly value of +0.3 °C for the week ending 8 December 2013. The IOD typically has little effect on Australian climate during the months from December to April. This is due to the IOD pattern being unable to form once the monsoon trough moves south over the eastern tropical Indian Ocean.

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 December) predicts NINO3.4 is most likely to remain within neutral values throughout the forecast period. The following forecast values are for the ensemble mean.

POAMA archive data is available here.

ENSO Dials

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

ENSO dial month+1 ENSO dial month+3 ENSO dial month+5

NINO3.4 outlook bar-graphs

The following graphs 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 bar graph month+1 NINO3.4 bar graph month+3 NINO3.4 bar graph month+5

IOD outlook bar-graphs

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.

IOD bar graph month+1 IOD bar graph month+3 IOD bar graph month+5

Past climate model summaries