ENSO Outlook
An alert system for the El Niño–Southern Oscillation

El Niño and La Niña outlook status


The status of the ENSO Outlook is determined using set criteria (described below) and expert analysis by climatologists at the Bureau of Meteorology. It is updated fortnightly.

El Niño

El Niño WATCH El Niño WATCH

"The chance of an El Niño developing in the coming season has increased. When these criteria have been met in the past, an El Niño event has developed around 50% of the time."

All of the following criteria need to be satisfied:

  1. Current climate state: ENSO phase is currently neutral or declining La Niña.
    • Either:
      SOI analogues: Of the 10 years that most closely resemble the current SOI pattern, 4 or more have shown El Niño characteristics.
    • Or:
      Sub-surface: Significant sub-surface warming has been observed in the western or central equatorial Pacific Ocean.
  2. Models: One-third or more of surveyed climate models show sustained warming to at least 0.8 °C above average in the NINO3 or NINO3.4 regions of the Pacific Ocean by late winter or spring.

El Niño ALERT El Niño ALERT

"The chance of an El Niño developing in the coming season has increased. When these criteria have been met in the past, an El Niño event has developed around 70% of the time."

Any three of the following criteria need to be satisfied:

  1. Sea surface temperature: A clear warming trend has been observed in the NINO3 or NINO3.4 regions of the Pacific Ocean during the past three to six months.
  2. Winds: Trade winds have been weaker than average in the western or central equatorial Pacific Ocean during any two of the last three months.
  3. SOI: The two-month average SOI is –7 or lower.
  4. Models: A majority of surveyed climate models show sustained warming to at least 0.8 °C above average in the NINO3 or NINO3.4 regions of the Pacific Ocean by the late winter or spring.

El Niño EL NIÑO

"An El Niño has been declared and is underway."

Any three of the following criteria need to be satisfied:

  1. Sea surface temperature: Temperatures in the NINO3 or NINO3.4 regions of the Pacific Ocean are 0.8 °C warmer than average.
  2. Winds: Trade winds have been weaker than average in the western or central equatorial Pacific Ocean during any three of the last four months.
  3. SOI: The three-month average SOI is –7 or lower.
  4. Models: A majority of surveyed climate models show sustained warming to at least 0.8 °C above average in the NINO3 or NINO3.4 regions of the Pacific until the end of the year.

La Niña

La Niña WATCH La Niña WATCH

"The chance of a La Niña developing in the coming season has increased. When these criteria have been met in the past, a La Niña event has developed around 50% of the time."

All the following criteria need to be satisfied:

  1. Current climate state: ENSO phase is currently neutral or declining El Niño.
    • Either:
      SOI analogues: Of the 10 years that most closely resemble the current SOI pattern, 4 or more have shown La Niña characteristics.
    • Or:
      Sub-surface: Significant sub-surface cooling has been observed in the western or central equatorial Pacific Ocean.
  2. Models: One-third or more of surveyed climate models show sustained cooling to at least 0.8 °C below average in the NINO3 or NINO3.4 regions of the Pacific Ocean by late winter or spring.

La Niña ALERT La Niña ALERT

"The chance of a La Niña developing in the coming season has increased. When these criteria have been met in the past, a La Niña event has developed around 70% of the time."

Any three of the following criteria need to be satisfied:

  1. Sea surface temperature: A clear cooling trend has been observed in the NINO3 or NINO3.4 regions of the Pacific Ocean during the past three to six months.
  2. Winds: Trade winds have been stronger than average in the western or central equatorial Pacific Ocean during any two of the last three months.
  3. SOI: The two-month average SOI is +7 or higher.
  4. Models: A majority of surveyed climate models show sustained cooling to at least 0.8 °C below average in the NINO3 or NINO3.4 regions of the Pacific Ocean by the late winter or spring.

La Niña LA NIÑA

"A La Niña has been declared and is underway."

Any three of the following criteria need to be satisfied:

  1. Sea surface temperature: Temperatures in the NINO3 or NINO3.4 regions of the Pacific Ocean are 0.8 °C cooler than average.
  2. Winds: Trade winds have been stronger than average in the western or central equatorial Pacific Ocean during any three of the last four months.
  3. SOI: The three-month average SOI is +7 or higher.
  4. Models: A majority of surveyed climate models show sustained cooling to at least 0.8 °C below average in the NINO3 or NINO3.4 regions of the Pacific Ocean until the end of the year.

 

Inactive

El Niño and La Niña Neutral INACTIVE

"An ENSO event is not active in the tropical Pacific Ocean and there are no signs of an El Niño or La Niña developing."

The ENSO Outlook status is updated each fortnight. The below graph shows the fortnightly values dating back to January 1980. The below table shows the monthly value of the ENSO Outlook for historical comparisons. The ENSO Outlook graph and table are not an official time-line of ENSO events. For the official history of El Niño and La Niña events see:

Fortnightly ENSO Outlook values

Monthly ENSO Outlook values

Legend

ENW El Niño WATCH
LNA El Niño ALERT
EN EL NIÑO
N INACTIVE
LNW La Niña WATCH
ENA La Niña ALERT
LN LA NIÑA

El Niño and La Niña years

Shading of text in the year column refers to years in which El Niño (red) or La Niña (blue) events began.

Historical values of the ENSO Outlook status prior to 2014 are based on the set criteria alone. Values from the beginning of 2014 include expert analysis by climatologists at the Bureau of Meteorology to make the final assessment on a status level having been reached.

El Niño WATCH continues

The ENSO Outlook remains at El Niño WATCH.

ENSO is currently neutral. While oceanic and atmospheric ENSO indices remain within neutral boundaries, sea surface temperatures in the tropical Pacific have steadily warmed since the beginning of the year. Above average temperatures are also evident in the sub-surface waters in the western tropical Pacific. The SOI has shown some fluctuations in recent weeks, mostly related to tropical activity, but also remains neutral.

All climate model outlooks show further warming of the Pacific is likely in the coming months, with seven reaching El Niño thresholds during the southern hemisphere winter of 2017.

El Niño WATCH means that there is approximately a 50% chance of El Niño developing in 2017, which is about twice the normal likelihood.

Further information on the current status of ENSO can be found at the link below.

Product code: IDCKGEAS00