El Niño Comes to an End

It’s official! The El Niño event of 2015-16 has ended.

According to NOAA, the sea surface temperatures in the so-called “Nino 3.4” region of the tropical Pacific have fallen below the El Niño threshold and ENSO-neutral conditions have returned.  But, this El Niño episode will not soon be forgotten.

Developing in the spring of 2015, this El Niño was one of the three strongest on record, along with the 1997-98 and 1982-83 events. Transferring heat from the ocean to the atmosphere, it helped make 2015 this planet’s warmest year on record. Coming on top of human-caused global warming, the new record was heads and shoulders above the previous one.

Influencing weather around the world, El Niño is probably best known in the US for bringing heavy rain (and the mudslides that go with it) to southern California. This time, however, the little rain that did come was not enough to end the multi-year drought plaguing the Golden State.

With exceptionally warm sea surface temperatures, the eastern Pacific hurricane season was extremely active. Eighteen named storms developed and thirteen became hurricanes. Hurricane Patricia, with winds measured at 200 mph, was the strongest hurricane ever recorded in the western hemisphere.

By contrast, the 2015 Atlantic Hurricane season was below average. It produced eleven named storms and four hurricanes. This relatively quiet season was largely the result of wind shear in the Gulf of Mexico, generated by El Niño, which helped to hinder most tropical development in the Atlantic basin.

Now that El Niño has dissipated, NOAA expects a La Niña episode – characterized by cooler than average Pacific sea surface temperatures – to develop in the autumn.

Data: NOAA/CPC

ENSO records date back to 1950. Data: NOAA/CPC

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About Melissa Fleming

Melissa Fleming is an environmental communicator and visual artist working at the intersection of art and science. She is passionate about exploring, learning, and sharing information about the natural world. She has presented her interdisciplinary work in a variety of mediums at venues and conferences around the world.