neutral conditions are present.
> Equatorial sea surface temperatures (SSTs) are near-average across the central
and east-central Pacific. They are above-average in the eastern Pacific Ocean.
> ENSO-neutral conditions have returned and are favoured to continue through at
least the months of March/April/May.
During the last four weeks, negative SST anomalies weakened in the central Pacific.
Meanwhile, above-average SSTs increased and expanded westward from the eastern Pacific.
During the last two months, negative subsurface temperature anomalies have dissipated across the equatorial Pacific Ocean.
Positive subsurface anomalies have increased along the thermocline across the tropical Pacific Ocean.
The ONI is based on SST departures from average in the Niño 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO.
(Defined as the three-month running-mean SST departures in the Niño 3.4 region.
El Niño: characterized by a positive ONI greater than or equal to +0.5ºC.
La Niña: characterized by a negative ONI less than or equal to -0.5ºC.
By historical standards, to be classified as a full-fledged El Niño or La Niña episode, these thresholds must be exceeded for a period of at least 5 consecutive overlapping 3-month seasons.
CPC considers El Niño or La Niña conditions to occur when the monthly Niño3.4 OISST
departures meet or exceed +/- 0.5ºC along with consistent atmospheric features. These anomalies must also be forecasted to persist for 3 consecutive months.)
The most recent ONI value (November 2016 – January 2017) is -0.7ºC.