The weak La Niña phenomenon has officially developed in the Pacific Ocean and its impact is clearly evident in the world's atmosphere.

Arab Weather - Weather experts at the Arab Weather Regional Center said, after following up on the latest computer modeling outputs for the deviation of the temperature of water bodies from the averages, that the central part of the Pacific Ocean in the region located on the equator is witnessing a clear cooling of the water surface temperature, as it decreased from its averages by an amount ranging between one and two degrees, and this means the official growth of the climate phenomenon (La Nina) which will continue with us during the coming months until spring.

NOAA officially announces the development of the La Nina phenomenon, but it is weak, which means its effects are less

The National Oceanic and Atmospheric Administration (NOAA) announced this week that conditions have officially formed for the weather event to be declared, after officials had been monitoring it for much of 2024, with the winter expected to develop right after the 2023-24 El Niño ended. Initial projections now call for La Niña to last through April 2025, then transition to ENSO-neutral between March and May 2025.

According to NOAA, sea surface temperatures in the tropical Pacific have been close to ENSO-neutral since April 2024. This is the threshold for La Niña to occur and the equatorial seas to be below normal. The atmospheric conditions necessary for La Niña to develop have already been present for several months, including “stronger-than-normal trade winds, increased clouds and precipitation over Indonesia, and drier conditions over the central Pacific.”

There is a 60% chance that La Niña will continue until spring 2025.

This new La Niña is expected to last through the spring months in the Northern Hemisphere with a 60% chance, according to the National Oceanic and Atmospheric Administration, leaving plenty of room for La Niña to last longer than expected. However, the effects of La Niña are likely to be less pronounced than previous La Niña cycles because this year's La Niña is classified as weak according to the NOAA report, but its effects have been evident in the past months and up until now.

What is La Niña?

Arab Weather experts explained that the term "La Niña" refers to a large-scale ocean and atmospheric climate phenomenon associated with a periodic cooling in sea surface temperatures (SSTs) across the central and eastern equatorial Pacific Ocean. The "La Niña" phenomenon represents the cold phase of the "ENSO" cycle, meaning that water temperatures in the equatorial part of the ocean are cooler than average and trade winds are stronger than normal.

La Niña is statistically associated with the strengthening of the Siberian High in winter in the western Mediterranean and with above-average rainfall in the western Mediterranean.

Arab weather forecasters believe that the La Niña phenomenon is statistically linked to the intensification of the Siberian high's influence on the Arabian Peninsula and the Levant during the winter. The La Niña phenomenon often affects the Arab region with a lack of rain in the Levant, but the opposite happens in the Maghreb, where rain increases and temperatures drop below average. The chance of floods and torrents increases in the Maghreb, while the chance of drought increases in the Levant as a result of the Siberian high's control.

This is what we see implicitly on the ground, as the countries of the eastern Mediterranean basin were affected by a repeated extension of the Siberian high and a severe shortage in rainfall, while the countries of the Maghreb were affected by strong winter depressions that brought abundant rain and snowfall several times over the high mountainous elevations, especially northern Algeria, since the beginning of winter. Computer modeling also shows that the abundance of rain will continue during the coming period.

La Niña's relationship to recent wildfires in the southwestern United States

California has recently been hit by a severe wave of fires, and experts at the Arab Weather Center explain that one of the causes of the fires is the severe lack of rainfall recently, in contrast to the previous year when the El Niño phenomenon prevailed in the tropical Pacific Ocean. La Niña usually causes dry weather in the southern and western regions of the United States, while other parts of the country are experiencing wetter weather, which is the condition that was already prevalent during the past period.

The drought caused by the La Niña phenomenon has increased the outbreak of fires at an unusual time of the year, especially since the fires occurred during the winter. Here, the importance of studying these climate cycles and their impact on the global climate is highlighted, as the effects may not be limited to floods, heat waves and drought only, but rather double the chances of fires occurring in some areas around the world.

Climate cycles are just one part of a larger pattern that drives global weather systems.

La Niña also affects the pattern of air currents and global weather in many ways, which may lead to changes in temperature and precipitation in different parts of the world. However, it cannot be said with certainty that its effects will be inevitable in terms of its impact on the world's climate, as all likely effects are the result of statistical processing of the years in which this phenomenon occurred, with the need to emphasize that these climate cycles are only an integral part of giant patterns that drive global weather systems.

And God knows best.