Climate Model Summary

Climate Model Summary Archive: 26 October 2011

Issued on Wednesday 26 October 2011 |

La Niña re-established in the Pacific


As detailed in the ENSO Wrap-Up, the central tropical Pacific Ocean is now in the early stages of a late-forming La Niña event. Atmospheric indicators are also now close to or beyond La Nina thresholds.

The majority of dynamical models surveyed by the Bureau of Meteorology suggest that the central Pacific Ocean is likely to continue to cool over the next few months with a return to neutral values by the southern hemisphere autumn.

The Bureau's POAMA model predicts that the central Pacific Ocean temperatures will favour cool conditions to persist until at least autumn 2012. Please Note: The Bureau has moved to a new version of its POAMA model (POAMA-2).

Model Outlooks

The following table summarises the opinion of National Climate Centre (NCC) climatologists regarding the outputs from various long range forecast models. The model set contains eight reputable ocean or coupled ocean/atmosphere climate models that take into account complex physical ocean processes. NCC's interpretation may not necessarily be the same as the organisations producing the model output. You are therefore encouraged to follow the hyperlinks to the various institutions listed in the table.

See About ENSO outlooks for details on the models and a summary of the terms used.

Forecast Start Date 1-3 MONTHS
(Nov 2011 to Jan 2012)
(Feb 2012 to Apr 2012)
Australian Bureau of Meteorology
15 October Cool Cool/Neutral
23 October Cool Cool
Japan Met. Agency
12 October Neutral Neutral
UK Met Office
1 October Cool Cool#
NASA Goddard GMAO (US)
1 September Cool/Neutral Neutral
System 3
1 October Cool Cool/Neutral
Korean Met. Administration
1 September Neutral Neutral

# Forecast period ends before April.

Note that some links above may be updated to more recent forecasts than listed here.

POAMA Forecasts

The POAMA model, run at the Bureau of Meteorology, generates a new forecast on day 1 and day 15 of each month for the following eight months. The most recent model run predicts NINO3.4 will be cooler than average before returning to neutral values by autumn 2012.

The IOD index is currently positive, with the latest weekly value at +0.49. POAMA outlooks suggest this positive IOD event will return to neutral values by the southern hemisphere summer. Positive IOD events tend to increase the chance of below average rainfall over southeastern Australia.

December 2011

The most recent POAMA model run (15 October 2011) predicts the average NINO3.4 temperature anomaly for December 2011 will be −1.1 °C and the frequency distribution is as follows:
below −0.8 °C: 100.0% (Cool)
−0.8 °C to +0.8 °C: 0.0% (Neutral)
above +0.8 °C: 0.0% (Warm)

March 2012

For March 2012, the average NINO3.4 index is −0.8 °C and the frequency distribution is:
below −0.8 °C: 40.0% (Cool)
−0.8 °C to +0.8 °C: 60.0% (Neutral)
above +0.8 °C: 0.0% (Warm)

Similar data for other months can be accessed by following the "POAMA" link in the table above.

Users should exercise caution when interpreting these forecasts and are encouraged to view the actual model outputs by following the web links. Frequent updates of the latest observational data with relevant commentary are available on the Bureau's ENSO Wrap-Up page.

This survey last updated on the 26th of October 2011.
Next update expected 9th of November 2011.

See also the ENSO Wrap-up archive here.

Past climate model summaries