NOAA announces the arrival of El Niño

This year’s El Niño is likely to be weak, with little influence on weather through early spring, say NOAA forecasters.

Earth with orange along equator and orange patches north and south of it.

Difference from average sea surface temperatures at the equator in the tropical Pacific during January, 2019. Image via NOAA.

NOAA’s Climate Prediction Center issued an El Niño Advisory on February 14, 2019, indicating the climate pattern has taken effect and is likely to continue through the spring. While the El Niño is expected to be weak, it may bring wetter conditions across the southern half of the U.S. during the coming months.

El Niño is is a natural ocean-atmospheric phenomenon marked by warmer-than-average sea surface temperatures in the central Pacific Ocean near the equator. Typical El Niño patterns during winter and early spring include below-average precipitation and warmer-than-average temperatures along the northern tier of the U.S. and above-normal precipitation and cooler conditions across the U.S. South. although impacts vary during each El Nino event.

Mike Halpert is deputy director of NOAA’s Climate Prediction Center, and ENSO forecaster. Halpert said:

El Niño conditions across the equatorial Pacific have come together and we can now announce its arrival. While sea surface temperatures are above average, current observations and climate models indicate that this El Nino will be weak, meaning we do not expect significant global impacts through the remainder of winter and into the spring.

Forecasters say there is about a 55 percent chance that El Niño conditions will continue through the spring.

Flowchart.

View larger. | The El Niño decision tree. Summary of decision process in determining El Niño conditions. Image via NOAA Climate.gov/Glen Becker and Fiona Martin.

Scientists say that some of the above-normal precipitation this winter in parts of the U.S. West can be attributed to another climate phenomena, called the Madden-Julian Oscillation (MJO) – a large-scale coupling between atmospheric circulation and tropical deep convection – rather than El Niño influences. The MJO can trigger enhanced rainfall along the West Coast.

Last winter, La Niña took effect in October 2017 and lasted through April 2018 before a return to neutral conditions.

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Bottom line: NOAA has issued an El Niño Advisory, indicating the climate pattern has taken effect and is likely to continue through spring 2019.

Source: El Niño/Southern Oscillation (ENSO) Diagnostic Discussion

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