El Niño approaches its end and enters the neutrality phase

El Niño, a phenomenon characterized by the abnormal and persistent warming of the surface of the Pacific Ocean, is coming to an end and is close to neutral. According to the National Institute of Meteorology (Inmet), since the beginning of April, a substantial cooling of Sea Surface Temperatures (SSTs) has been recorded, reaching, in the last five days, values ​​close to 0,5ºC (degrees Celsius ) above average, in the reference area for defining the event, called the Niño 3.4 region.

This temperature value is considered the limit for the beginning of the neutral phase of the ocean (figure 1). Also according to Inmet, before this, the SSTs were already constantly cooling in the Equatorial Pacific. Between the months of February and March 2024, temperatures fell from 1,5ºC to 1,2ºC above average.

Currently, climate models analyzed by the Institute indicate that the neutrality condition should continue until mid-June.

Transition to La Niña

Simultaneously with what happens with the El Niño phenomenon, in some areas of the Equatorial Pacific, such as the west coast of South America, temperatures are already colder than normal (green tones in figure 2).

The persistence and expansion of these colder areas towards the central part of the ocean are favorable conditions for the formation of the La Niña phenomenon, predicted for the second half of the year, as reported in the bulletin published by Inmet.

La Niña consists of a decrease in the surface temperature of the waters of the Central and Eastern Tropical Pacific Ocean. According to Inmet's analysis, the probability is that in the quarters of June, July and August, that is, mid-winter, Brazil will already be under the effects of the phenomenon.

The intensity of La Niña cannot yet be confirmed, but generally the impacts caused by the phenomenon are: above-average rainfall in the North and Northeast regions of Brazil. In the South Region and part of the Central-West and Southeast, rain occurs irregularly and the risk of drought or drought increases, especially during spring and summer.