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Published June 26, 2013
El Niño Status and ForecastData Source(s): NOAA-Climate Prediction Center (CPC), International Research Institute for Climate and Society (IRI)
Sea surface temperatures (SSTs) are close to average for this time of year across the equatorial Pacific Ocean, signaling that the El Niño-Southern Oscillation (ENSO) continues to be in its neutral phase. The NOAA-Climate Prediction Center (CPC) notes that a decrease in SSTs in the eastern Pacific in mid-June quickly returned to average. This cooling was not interpreted as a move towards a developing La Niña event. Wind patterns, reflected in the Southern Oscillation Index (SOI), are also largely close to average across the equatorial Pacific, further indicating that the development of a La Niña or El Niño event is not imminent (Figure 14a).
Official SST outlooks issued jointly by the CPC and the International Research Institute for Climate and Society (IRI) continue to indicate that neutral conditions are likely to persist into next year (Figure 14b). These chances are greater than the long-term average chances (green line in Figure 14b). Most dynamical and statistical models agree that neutral conditions are the most likely outcome over the next several months, but the IRI also notes that a few statistical models were leaning towards a weak La Niña event developing in this period.Notes:
The first figure shows the standardized three month running average values of the Southern Oscillation Index (SOI) from January 1980 through May 2013. The SOI measures the atmospheric response to SST changes across the Pacific Ocean basin. The SOI is strongly associated with climate effects in the Southwest. Values greater than 0.5 represent La Niña conditions, which are frequently associated with dry winters and sometimes with wet summers. Values less than -0.5 represent El Niño conditions, which are often associated with wet winters.
The second figure shows the International Research Institute for Climate and Society (IRI) probabilistic El Niño-Southern Oscillation (ENSO) forecast for overlapping three-month seasons. The forecast expresses the probabilities (chances) of the occurrence of three ocean conditions in the ENSO-sensitive Niño 3.4 region, as follows: El Niño, defined as the warmest 25 percent of Niño 3.4 sea-surface temperatures (SSTs) during the three month period in question; La Niña conditions, coolest 25 percent of Niño 3.4 SSTs; and neutral conditions where SSTs fall within the remaining 50 percent of observations. The IRI probabilistic ENSO forecast is a subjective assessment of current model forecasts of Niño 3.4 SSTs that are made monthly. The forecast takes into account the indications of the individual forecast models (including expert knowledge of model skill), an average of the models, and other factors.
For a technical discussion of current El Niño conditions::
For more information about El Niño and to access graphics similar to the figures on this page::
Southwest Climate Outlook Staff
- Michael Crimmins, UA Extension Specialist
- Stephanie Doster, Institute of the Environment Editor
- Gregg Garfin, Founding Editor, Institute of the Environment
- Zack Guido, Managing Editor, CLIMAS Associate Staff Scientist
- Nancy J. Selover, Arizona State Climatologist
- Jessica Dollin, CLIMAS Publications Assistant
- Dave Dubious, New Mexico State Climatologist
Please direct your Southwest Climate Outlook comments and suggestions to Zack Guido.
The CLIMAS Web site contains official and non-official forecasts, as well as other information. While we make every effort to verify this information, please understand that we do not warrant the accuracy of any of these materials.... Read full disclaimer