World Meteorological Organization (WMO): El Niño alert

Weather of Arabia - The possibility of an El Niño phenomenon developing later this year is increasing, according to a new update issued by the World Meteorological Organization (WMO). This will have adverse effects on weather and climate patterns in many regions of the world in response to the prolonged La Niña phenomenon, and is likely to lead to higher global temperatures.

Now that the extraordinarily stubborn La Niña has ended after three years, the equatorial Pacific Ocean is now experiencing ENSO-neutral conditions (no El Niño or La Niña).

60 percent chance of going from a neutral El Niño state to an El Niño event

There is a 60 percent chance of a transition from a neutral El Niño state to an El Niño event during the May-July 2023 period, rising to approximately 70 percent in the June-August period, and to 80 percent in the period between July and September, as updated based on input from the WMO Global Long-Range Forecasting Centers and expert assessment.

At this point, there is no indication of the strength or duration of the El Niño phenomenon.

Professor Petteri Taalas, Secretary-General of WMO, said: “We have just experienced the eight warmest years since records began, although we have had a cold La Niña over the past three years, which acted as a temporary brake on the increase in global temperatures. It is likely that The development of El Niño leads to a new rise in global warming, increasing the chance of reaching new temperature records.”

According to WMO's State of the Global Climate reports, 2016 was the warmest year on record due to the "double whammy" of a very strong El Niño and anthropogenic warming due to greenhouse gases. Since the impact on global temperatures is usually seen in the year following the development of an El Niño, it is likely to be more pronounced in 2024.

Professor Taalas said: “The world should prepare for the development of El Niño, which is often associated with an increase in temperature, drought or precipitation in different parts of the world. El Niño may bring a respite from drought in the Horn of Africa and other effects associated with La Niña, and even "It could also lead to the development of more extreme weather and climate events. This highlights the need for the UN Early Warning for All initiative to keep people safe."

No two El Niño events are the same, and the effects depend in part on when of the year they occur. Therefore, WMO and NMHSs will monitor developments closely.

El Niño is a natural weather pattern associated with an increase in ocean surface temperatures in the central and eastern tropical Pacific Ocean. El Niño events occur on average every two to seven years, and episodes usually last for periods of 9 to 12 months.

El Niño is usually associated with increased precipitation in parts of southern South America, the southern United States, the Horn of Africa, and Central Asia.

Conversely, El Niño may also cause severe droughts over Australia, Indonesia and parts of South Asia.

During the northern hemisphere summer, warm El Niño waters can feed hurricanes in the central/eastern Pacific Ocean, while inhibiting hurricane formation in the Atlantic Basin.

Seasonal update of global climate

El Niño and La Niña phenomena are two major drivers - though not the only ones - of Earth's climate system.

In addition to the long-standing ENSO Update, WMO now releases regular Global Seasonal Climate Updates (GSCU), incorporating the impacts of all other major climate drivers such as the North Atlantic Oscillation, Arctic Oscillation, and the bipolarity of the Indian Ocean.

The latest update states that “because warmer-than-average sea surface temperatures are generally predicted over ocean regions, they contribute to the widespread prediction of higher-than-normal temperatures over land regions. Without exception, positive anomalies are expected in Temperatures over all land areas in the northern and southern hemispheres.

The WMO El Niño, Southern Oscillation and Global Monsoon Climate Updates are based on forecasts from the WMO Global Long-Range Forecasting Centers and are made available to support governments, the United Nations, decision-makers and stakeholders in climate-sensitive sectors in Mobilize preparations and protect lives and livelihoods.

Probabilistic forecasts of surface air temperature and precipitation for the May–July 2023 season. The ternary class with the highest forecast probability is shaded. The most probable category for below normal, above normal, and near normal rates is shaded in blue, red, and gray, respectively, for temperature averages, and in orange, green, and gray, respectively, for precipitation rates. The white areas indicate equal probabilities for all categories in both cases. The base period is 1993-2009.

Recent developments in ocean and atmospheric conditions

As of February 2023, there has been a significant increase in sea surface temperatures in the equatorial Pacific Ocean, with temperatures significantly warming along the coast of South America.

As of mid-April 2023, sea surface temperatures and other atmospheric and ocean indices in the central eastern tropical Pacific correspond to neutral El Niño-Southern Oscillation (ENSO) conditions. In the atmosphere, convection activity over the equatorial Pacific Ocean near the International Date Line is close to normal.

It should be noted, however, that in the Northern Hemisphere the “spring forecasting barrier,” a period of somewhat less predictive skill, is not over yet. However, these recent developments in ocean and atmospheric conditions in the tropical Pacific Ocean, together with current forecasts and expert assessments, indicate a strong probability of an El Niño event in the early second half of 2023, and persistence through the remainder of the six-month forecast period. .

The WMO El Niño/La Niña Update is a collaborative effort between WMO and the International Research Institute for Climate and Society (IRI), USA, and is based on contributions from experts around the world, including the following institutions: Australian Bureau of Meteorology BoM, CIIFEN International Center for Research on El Niño, China Meteorological Administration (CMA), Climate Prediction Center (CPC) and Climate Services for El Niño-Southern Oscillation Applications (ENSO) in the Pacific Ocean (PEAC) of the National Oceanic and Atmospheric Administration NOAA USA, European Center for Medium-Range Weather Forecasts (ECMWF), Météo-France, Indian Meteorological Department (IMD), Indian Institute of Tropical Meteorology (IITM), International Bureau The Monsoon Project (IMPO), Japan Meteorological Agency (JMA), Korea Meteorological Administration (KMA), United Kingdom Met Office, Meteorological Service Singapore (MSS), WMO Global Long Range Forecast Production Centers Including the main center for long-range forecasts based on multi-model forecast ensembles (LC-LRFMME).