Climate Model Summary

Climate Model Summary Archive: 27 April 2011

Models predict neutral conditions by southern hemisphere winter


As detailed in the ENSO Wrap-up, La Niña conditions continue to weaken in the tropical Pacific, with a forecast return to neutral conditions by the southern hemisphere winter.

Most dynamical models surveyed by the Bureau of Meteorology indicate a continued warming of the equatorial Pacific Ocean temperatures during the coming months with the rate of warming varying between models. Observed sea surface temperatures (e.g., NINO3.4) continue to approach 'neutral' values, with the majority of models predicting neutral conditions by the southern winter, 2011.

The Bureau's POAMA model suggests that central Pacific Ocean temperatures will continue to warm through the autumn and winter months, with the average of all thirty POAMA forecasts favouring neutral conditions throughout winter.

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
(May 11 to Jul 11)
(Aug 11 to Oct 11)
Australian Bureau of Meteorology
11 April Neutral Neutral/Warm
System 3
1 March Cool/Neutral Neutral
GloSea *
UK Met Office
1 March Cool/Neutral Neutral/Warm #
11 April Neutral Neutral
NASA Goddard GMAO (US)
1 April Neutral/Warm Warm
Japan Met. Agency
15 March Neutral/Warm Warm/Neutral
Korean Met. Administration
1 March Cool/Neutral Neutral^
BCC/CMA (China)
Unavailable Unavailable Unavailable

# Model forecast is run only until mid-August
^Model forecast is based on 1 March 2011 run and should be viewed with this consideration - updated forecasts are likely during the next fortnight

* Note that this page requires a password, freely available from UK Met Office
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 every day for the following eight months starting with the latest observations. The average of the most recent 30 model runs predict neutral conditions to persist through winter, with NINO3.4 predicted to continue its warming trend, but remain within neutral parameters.

The IOD is currently neutral with the latest weekly value of the IOD index at −0.08. POAMA predicts that the IOD index will remain neutral through the southern hemisphere autumn and winter seasons.

June 2011

For the 30 runs of POAMA between 13 March 2011 and 11 April 2011, the average NINO3.4 temperature anomaly for April 2011 is 0.29°C and the frequency distribution is as follows:
below −0.8°C: 0.0% (Cool)
−0.8°C to +0.8°C: 100.0% (Neutral)
above +0.8°C: 0.0% (Warm)

September 2011

For September 2011 the average NINO3.4 index is slightly warmer at 0.78°C and the frequency distribution is:
below −0.8°C: 0.0% (Cool)
−0.8°C to +0.8°C: 46.7% (Neutral)
above +0.8°C: 53.3% (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 30th March 2011.
Next update expected 27th April 2011.

See also the ENSO Wrap-up archive here.

Past climate model summaries