Climate Model Summary
Model Summary forecasts are no longer available
We are streamlining some climate pages including removal of the Model Summary.
From 10 December our climate information is available on the Southern Hemisphere monitoring and Southern Hemisphere outlooks pages.
If you have any feedback, please use our Feedback Form.
Average of international model outlooks for the Niño3.4 index
Average of international model outlooks for the Indian Ocean Dipole (IOD) index
Dial details
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.
The ENSO and IOD dials are calculated by simply averaging the ensemble means from all the models surveyed. Values are not representative of the potential spread of the forecast outcomes. Therefore, the dials are intended to be used as a quick reference to determine whether the models are showing a warming trend, a cooling trend, or neither. More information is provided in the graphs presented in other sections.
More information:
Niño3.4 covers the central Pacific region.
Niño3.4 multi-model forecast for the months ahead
Bar graph details
The graphs are based on the ensemble mean for the most recent model run.
These graphs show the average forecast value of Niño3.4 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.
Niño3.4 recent observations and multi-model long-range forecast
Timeseries graph details
This timeseries graph shows recent monthly observations, as well as long-range forecasts for the Niño3.4 index from a range of international models. Monthly observations are from the OISSTv2 (1991-2020 base period) dataset, represented by the left side dashed line. Each coloured line to the right represents the ensemble mean forecast from nine international climate models including the Bureau's model. The graph is updated each month, with available data updated fortnightly.
More information:
IOD index multi-model forecast for the months ahead
Bar graph details
The graphs are based on the ensemble mean for the most recent model run.
These 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 and atmospheric patterns in the Pacific, Indian and Southern ocean regions. Specific regions are monitored, as they can indicate the presence, or potential development, of ENSO (El Niño/La Niña), Indian Ocean Dipole (IOD) phases and Southern Annular Modes. Pacific and Indian ocean indices are updated fortnightly, but the SAM index can change rapidly so it is updated daily. The first SAM button matches the Niño and IOD fortnightly issue date. During the following fortnight the 'Latest SAM' chart will diverge.
Niño34 predictions for the next 5 months
Niño34 probabilities
Product code: IDCK000073
More information:
Model details
Model selection
All the models included in this page have been documented in the peer-reviewed international scientific literature and have skill in predicting El Niño-Southern Oscillation (ENSO) and Indian Ocean patterns. They are all coupled General Circulation Models, and hence simulate both atmospheric and oceanic processes using physics rather than statistics. Most have been run routinely for a number of years and are subject to regular revision and update with the aim of continuous improvement. They represent the state-of-the-art of climate prediction systems and offer useful guidance up to about nine months. The majority of models used in our survey are formally recognised by the World Meteorological Organization as Global Producing Centres for long-range forecasts.
All models use an ensemble method, where several forecasts are run at the same time using slightly different initial conditions. While all models use ensemble techniques, the number of ensembles differs for each model.
The data presented on these pages is the 'ensemble mean' which is the average of all the model-runs performed by each model, each month. The ensemble mean therefore flattens out the potential forecast outcomes and doesn't show the full spread of the possible forecast scenarios.
More information about these models
[an error occurred while processing this directive]The webpage
This webpage surveys the latest output from several reputable climate models developed at leading international climate agencies. Data from these models is analysed and displayed in graphs and dials to show how temperature patterns in the Indian and Pacific ocean are likely to change over the coming six-months. These patterns in the oceans have been shown to have a significant impact on Australian temperature and rainfall patterns (e.g. cooling of the tropical Pacific Ocean during La Niña events is typically associated with increased rainfall and cooler daytime temperatures in Australia).
When the models are in agreement, then there is higher confidence in the model outlooks. When the models are showing a large spread or large variety of outcomes, there is a larger amount of uncertainty associated with the forecast.
The models
All the models included in this page have been documented in the peer-reviewed international scientific literature and have skill in predicting El Niño-Southern Oscillation (ENSO) and Indian Ocean patterns. They are all coupled General Circulation Models, and hence simulate both atmospheric and oceanic processes using physics rather than statistics. Most have been run routinely for a number of years and are subject to regular revision and update with the aim of continuous improvement. They represent the state-of-the-art of climate prediction systems and offer useful guidance up to about nine months. The majority of models used in our survey are formally recognised by the World Meteorological Organization as Global Producing Centres for long-range forecasts.
Update schedule
The Climate Model Summary is updated on the 12th of each month (or the next working day following the 12th) when model data becomes available. Data for the Bureau's model, ACCESS–S, is updated fortnightly along with several other models that also provide more frequent updates during the month.
The ensemble technique
All models use an ensemble method, where several forecasts are run at the same time using slightly different initial conditions. While all models use ensemble techniques, the number of ensembles differs for each model.
Important note
The data presented on these pages is the 'ensemble mean' which is the average of all the model-runs performed by each model, each month. The ensemble mean therefore flattens out the potential forecast outcomes and doesn't show the full spread of the possible forecast scenarios.
The dials
The ENSO and IOD dials (from the Overview section) are calculated by simply averaging the ensemble means from all the models surveyed. Values are not representative of the potential spread of the forecast outcomes. Therefore, the dials are intended to be used as a quick reference to determine whether the models are showing a warming trend, a cooling trend, or neither. More information is provided in the graphs presented in other sections.
Background information
Related sites
[an error occurred while processing this directive]
History
Model data are provided for Bureau of Meteorology use by the agencies detailed in Model Summary – Models. Respective agency copyright applies to these data.
A neutral Pacific likely for remainder of 2017
The El Niño-Southern Oscillation (ENSO) is neutral. All models now suggest sea surface temperatures in the tropical Pacific Ocean will fall short of El Niño thresholds, with ENSO-neutral the most likely outcome for the remainder of winter and spring.
The Indian Ocean Dipole (IOD) is currently neutral but recent temperature patterns and model outlooks suggest a developing positive IOD may influence rainfall patterns during late winter and early spring. A positive IOD is typically associated with below average winter-spring rainfall over southern and central Australia.
NINO3.4 outlook
The latest outlooks from the eight surveyed models all suggest that the central tropical Pacific Ocean will remain at temperatures consistent with a neutral ENSO throughout the forecast period. This is in contrast to model outlooks from earlier in the year that suggested an increased chance of El Niño developing during 2017.
The easing away from El Niño thresholds in the models is the result of weaker than expected coupling between the Pacific Ocean and overlying atmosphere at the end of the March/April "Coastal El Nino". This event, which saw sea surface temperatures (SSTs) rise to around 5 °C above normal off the Peruvian coast, was forecast to bring weakened trade winds, warmer central Pacific SSTs, and ultimately a basin-wide El Niño.
While SSTs in the central tropical Pacific have been warmer than average since the beginning of the year, the NINO3.4 SST index has remained consistently within ENSO-neutral values. The most recent weekly NINO3.4 value (to 11 June) is +0.5 °C.
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 latest weekly IOD index value to 11 June is –0.2 °C, within neutral boundaries. Three of the six surveyed models suggest index values are likely to meet or exceed the positive IOD threshold of +0.4 °C, from July and extend into early spring. A positive IOD is typically associated with below average winter-spring rainfall over southern and central Australia.
While index values above the positive IOD threshold would need to be sustained for at least eight weeks in order for 2017 to be classified as a positive IOD year, borderline conditions may still affect Australian rainfall patterns, particularly if coinciding with widespread cooler than average temperatures in the eastern Indian Ocean.
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 4 June) indicates NINO3.4 will start to cool during winter, but remain neutral throughout the forecast period.
The forecast values, shown below in bold, are for POAMA's ensemble mean.
Product code: IDCKGL0000
Unless otherwise noted, all maps, graphs and diagrams in this page are licensed under the Creative Commons Attribution 4.0 International Licence
