Climate Model Summary

Climate Model Summary Archive: 19 September 2012

Issued on Wednesday 19 September 2012 |

Pacific remains close to El Niño thresholds

Summary

As detailed in the ENSO Wrap-Up, tropical Pacific Ocean temperatures are close to values commonly associated with an El Niño event, however atmospheric indicators of ENSO such as trade winds, cloud patterns and the Southern Oscillation Index (SOI) have remained short of El Niño thresholds. To be considered an ENSO event, climatologists look for sustained signals in both the ocean and atmosphere over several months.

Most dynamical models surveyed by the Bureau of Meteorology suggest that sea surface temperatures in the tropical Pacific will maintain values around El Niño thresholds before returning to clearly neutral values towards the end of 2012 or early 2013. This is despite an easing in the strength of the warming signal predicted by the most recent run of model forecasts. Climatologists will continue to monitor conditions and outlooks closely for any further developments.

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 seven 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
(Oct to Dec 2012)
4-6 MONTHS
(Jan to Mar 2013)
POAMA
Australian Bureau of Meteorology
1 September Neutral Neutral/Warm
CFSv2
NCEP (US)
18 September Warm Neutral
ARPEGE*
MeteoFrance
1 September Neutral Neutral
GEOS-5
NASA Goddard GMAO (US)
1 September Warm Warm
System 4
ECMWF (EU)
1 September Neutral/Warm Neutral
JMA/MRI-CGCM
Japan Met. Agency
1 September Warm Warm
GloSea
UK Met Office
Not available Not available Not available

# Forecast only includes January.
* A password is currently required to view this forecast.

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 of each month for the following eight months. The most recent model run (September) predicts NINO3.4 has peaked and is likely to fall below the El Niño threshold during spring and remain neutral for the remainder of the forecast period.

The IOD index is currently positive with the most recent index value of +0.6 recorded for the week ending 16 September 2012. The latest forecast from the POAMA model predicts the index will return to neutral values towards the end of spring.

November 2012

The most recent POAMA model run (September) predicts the average NINO3.4 temperature anomaly for November 2012 will be +0.5 °C and the frequency distribution is as follows:
below −0.8 °C: 0.0% (Cool)
−0.8 °C to +0.8 °C: 96.7% (Neutral)
above +0.8 °C: 3.3% (Warm)

February 2013

For February 2013, the average NINO3.4 temperature anomaly is +0.6 °C and the frequency distribution is as follows:
below −0.8 °C: 0.0% (Cool)
−0.8 °C to +0.8 °C: 63.3% (Neutral)
above +0.8 °C: 36.7% (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 19 September 2012.
Next update expected 3 October 2012.


See also the ENSO Wrap-up archive here.

Past climate model summaries