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Writer's pictureMarco Morales, Ph.D.

El Niño and the Rain

You have probably heard several people say in this year of 2023 that the El Niño phenomenon will bring less rainfall to Guatemala.


Recently, many people in the Metropolitan area of Guatemala observed that the rainfall in the first half of May 2023 has not been consistent, and the month has experienced unusually high temperatures for this time of the year. Colleagues in the Southwest region made the same observation recently.


But are we already experiencing a year of very little rain and excessive heat? Has climate change won the battle?


In these matters, one should not be swayed by personal impressions or short-term memory. While everyone's perception is important, it is necessary to rely on actual data, analyze it in light of forecasts, and continue monitoring the climate. This is because it is a cycle with various variables that are not stable over time.


What is referred to as the "El Niño phenomenon"?

The "El Niño-Southern Oscillation" is known as ENSO, which refers to the climatic phenomenon that encompasses both the El Niño and La Niña events. ENSO describes the changes in sea surface temperature patterns and winds in the tropical Pacific Ocean, which can lead to the occurrence of an El Niño or La Niña event.


The El Niño event occurs when sea surface temperatures in the central and eastern tropical Pacific Ocean are warmer than normal for a sustained period.


What does El Niño have to do with the presence or absence of rainfall?

During an El Niño ENSO event, the increase in ocean temperature can cause droughts in some parts of the world (such as Australia and Indonesia), while causing floods in others (such as the west coast of South America).


In general terms, the El Niño phenomenon in Central America is associated with drought conditions and water scarcity.


The increase in sea temperatures in the eastern and central Pacific can result in a weakening of the trade winds, which blow from east to west and help transport moisture from the ocean to land. With weakened trade winds, the amount of moisture reaching the region is reduced, which can lead to droughts and decreased precipitation in the area.


What is the climate outlook for 2023?

It is necessary to know the probability of each ENSO state occurring throughout the year. According to the IRI ENSO Forecast (April 2023), for the May-July 2023 trimester, the probability of an El Niño state is 62%, while there is only a 38% chance of neutral conditions. For the remaining quarterly groupings in 2023 (June-August, July-September, etc.), the probabilities of El Niño are above 75%.


With this knowledge, meteorologists create rainfall models to analyze the outlook. For the May-July trimester, INSIVUMEH (2023) expects normal to above-normal rainfall conditions in Guatemala.

Climate Perspective Rainfall Map for the May-July 2023 quarter. The described categories are: AN for above normal, N for normal, and BN for below normal. Source: LXXI Central America Climate Forum, INSIVUMEH, 2023.


These analyses are regularly updated and published, so it is important to stay informed. In the case of Guatemala, INSIVUMEH publishes the quarterly climate outlook (access it here: https://insivumeh.gob.gt/wp-content/uploads/2023/04/perspectivaClimatica_MJJ2023_insivumeh-3.pdf ).


This article was published on 15/05/2023 in La Hora GT: https://lahora.gt/opinion/marco-morales/2023/05/15/el-nino-y-las-lluvias/


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