Model Outlooks of ENSO Conditions from June 2009

Product Code: IDCKGLM000

Predictions Point To Likely El Niño

Summary

As detailed in our ENSO Wrap-up, more evidence of a developing El Niño event has emerged in the past month. Sea surface temperatures (SST) over some of the equatorial tropical Pacific Ocean have warmed to above 1°C above normal, Trade Winds have been weaker than normal and the SOI remains negative at around −2.

All international coupled climate models surveyed here are predicting warming of Pacific Ocean SST in the outlook period and for SST to remain above El Niño thresholds throughout most of the second half of 2009. Forecasts from one of the models has slower and weaker warming (BCC_CGCM, which may be due to the lower initial SST in these forecasts) than the the other six, but all seven models predict El Niño conditions being established by the southern spring at the latest. There is now more agreement between the models than one month ago and predictability of ENSO conditions is high at this time of year. In this light the probability of an El Niño event occuring in 2009 is high; a definite increase from one month ago.

Model Outlooks

The following table summarizes the opinion of National Climate Centre climatologists regarding the outputs from various 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	2-4 MONTHS (Aug to Oct 09)	5-7 MONTHS (Nov 09 to Jan 10)
POAMA (run at Bureau of Met)	30 May - 28 June	Warm	Warm
System 3 ECMWF	01 June	Warm	Warm #
GloSea * UK Met Office	1 June	Warm	Not Available
CFS NCEP	18 - 27 June	Warm	Warm
CGCMv1 GMAO/NASA	June	Warm	Warm
BCC_CGCM BCC/CMA	24 - 31 May	Neutral	Warm
JMA-CGCM02 Japan Met. Agency	May	Warm	Warm #

# Model forecast is run only until the end of December
* 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 predicts the recent rapid warming to continue across the Pacific throughout the southern winter and for the warming to slow but to peak around mid-summer 2009-10. POAMA is therefore predicting El Niño conditions to become firmly established and to persist at least until the coming southern hemisphere summer.

While predictability is much lower than for the Pacific Ocean, POAMA is predicting a weak positive Indian Ocean Dipole (IOD) to persist through much of the outlook period, as is the NASA GMAO model, the other model surveyed here for which IOD forecasts are published.

September 2009

For the 30 runs of POAMA between 30 May and 28 June 2009, the average NINO3.4 temperature anomaly for SEPTEMBER is +1.4°C and the distribution of for AUGUST is as follows:
below −0.8°C: 0% (Cool)
−0.8°C to +0.8°C: 0% (Neutral)
above +0.8°C: 100% (Warm)

December 2009

And similarly for DECEMBER 2009 the average NINO3.4 index is +1.8°C and the distribution is:
below −0.8°C: 0% (Cool)
−0.8°C to +0.8°C: 0% (Neutral)
above +0.8°C: 100% (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 1 July 2009.
Next update expected late July 2009.