Climate Model Summary

Climate Model Summary Archive: 2 February 2011

Models predict La Niña will persist into the southern hemisphere autumn

Summary

As detailed in the ENSO Wrap-up, one of the strongest La Niña events on record continues to influence the Pacific Basin, however there are clear signs the event has passed its peak.

Although most dynamical models surveyed by the Bureau of Meteorology indicate a gradual decay of the cooler Pacific Ocean temperatures during the coming months, they also show that sea surface temperatures (e.g. NINO3.4) are likely to remain at levels typical of a La Niña event into the southern hemisphere autumn season.

The majority of models, with the exception of NCEP, predict the central Pacific will warm over the coming months, with a return to neutral conditions by late autumn. The NCEP model suggests that NINO3.4 will continue to exceed La Niña thresholds through autumn into early winter. The JMA and NASA models predict a faster warming of central Pacific sea surface temperatures with neutral conditions being reached as early as March.

The Bureau's POAMA model suggests that central Pacific Ocean temperatures will start to warm in coming months, with all thirty POAMA forecasts favouring a gradual weakening of La Niña conditions. However, despite a gradual weakening, POAMA predicts that the central Pacific Ocean will remain at temperatures typical of a La Niña event into the southern hemisphere autumn season. A gradual weakening of the event through autumn would be consistent with previous La Niña episodes.

Model Outlooks

The following table summarises the opinion of National Climate Centre 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.

MODEL /
GROUP
Forecast Start Date 1-3 MONTHS
(Feb 11 to Apr 11)
4-6 MONTHS
(May 11 to Jul 11)
POAMA
Australian Bureau of Meteorology
31 January Cool/Neutral Neutral
System 3
ECMWF (EU)
1 January Cool/Neutral Neutral
GloSea *
UK Met Office
1 January Cool Cool/Neutral #
CFS
NCEP (US)
30 January Cool Cool
CGCMv1
NASA Goddard GMAO (US)
1 January Cool/Neutral Neutral/Warm
JMA-CGCM02
Japan Met. Agency
1 January Cool/Neutral Neutral/Warm
KMA-SNU
Korean Met. Administration
1 December Cool Cool/Neutral
BCC_CMA
BCC/CMA (China)
Unavailable Unavailable Unavailable

# Model forecast is run only until the end of June
* 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 La Niña conditions will gradually weaken over the coming months with a return to neutral conditions by late autumn.

The IOD is currently neutral with the latest weekly value of the IOD index at +0.05. POAMA predicts that the IOD index will remain neutral through the southern hemisphere summer and into autumn.

March 2011

For the 30 runs of POAMA between 2 January 2011 and 31 January 2011, the average NINO3.4 temperature anomaly for March 2011 is −0.98°C and the frequency distribution is as follows:
below −0.8°C: 80.0% (Cool)
−0.8°C to +0.8°C: 20.0% (Neutral)
above +0.8°C: 0.0% (Warm)

June 2011

Similarly for June 2011 the average NINO3.4 index is −0.36°C and the frequency distribution is:
below −0.8°C: 10.0% (Cool)
−0.8°C to +0.8°C: 90.0% (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 2nd February 2011.
Next update expected 16th February 2011.


See also the ENSO Wrap-up archive here.

Past climate model summaries