El Niño Event Forecast

After nearly a year and a half of a La Niña weather system, North America is facing a major shift to an El Niño system.  Some climate scientists say there is a possibility of a "Super El Niño" event as the growing season progresses this summer.  The last Super El Niño event was experienced ten years ago, beginning in mid 2016 and continuing into 2017.

An El Niño system is formed when the surface temperatures of the Pacific Ocean, the world’s largest body of water, rise a couple of degrees above long-term normal — and this change has already taken place.  Effects of an El Niño system take several months to develop, but by early summer, it will cause air temperatures to rise above normal, along with a milder and wetter growing season, and this will continue into the fall and winter.

It's Still Early In The El Niño "Life Cycle"

Kent Moore, a professor of atmospheric physics at the University of Toronto, said that the magnitude of a weather event like a Super El Niño is hard to predict in its early stages.  He said that an El Niño system has already set up for this growing season and will continue into the fall and winter.  But Moore says only time will tell if this El Niño will be a ‘super’ event.

"We measure the strength of the El Niños by the temperature, and so a Super El Niño is just a very, very warm El Niño," Moore said.  "Because the sea-surface temperature in the Pacific is much warmer, we’ll definitely get an El Niño later in the summer and into the fall. As the weeks and months go by, we’ll get better guidance, and we’ll be surer as to whether or not we’re going to get one of these super events.”

Professor Moore explains that major system events, like La Niña and El Niño, are caused by temperature changes in the Pacific Ocean.  And, due to the sheer size of the Pacific, the upcoming El Niño event will have a worldwide effect.

The Impact Of El Niño Will Be Felt Globally

“The whole globe is warmer," he said.  "The biggest effect of El Niño is in Eastern Canada. In the States, it tends to get wetter. It’s a bit wetter off in the West Coast as well. Effects in Canada are more localized in the winter. That’s when we tend to get these weather patterns that are impacted by El Niño."

Looking into the upcoming fall and winter season later this year, Moore said that the El Niño effects will be seen in the central and western parts of the continent.  Depending on the severity of the system, the Canadian Prairies, the U.S. Midwest, and the Great Plains States could see a drier fall and winter, and milder temperatures into the winter months.

“If we do have a mild winter next year, it’s likely that the snowpack will be reduced. That will again lead to drier conditions come spring 2027, just because the ground will be very dry.”

What Does El Niño Mean For The Northwest?

In the Northwest, the impacts of El Niño show up mostly in the winter and affect Alaska differently than Idaho, Oregon, and Washington. According to National Oceanic and Atmospheric Administration’s [NOAA] Climate Prediction Center in Idaho, Oregon, and Washington, fall and winter are usually warmer and drier during El Niño events.  Though El Niño increases the chance of these weather patterns occurring, many other factors affect weather and climate in the Northwest, so the typical effects are not a certainty.

El Niño can also contribute to drought, wildfire, changes to marine productivity and salmon populations, and shoreline erosion. In, Idaho, Oregon, and Washington, a drier, warmer winter results in less precipitation overall and more precipitation falling as rain than snow. These impacts can lead to decreased runoff and summer water availability which can contribute to drought and increased wildfire risk. Larger waves and higher sea levels can also affect the coasts of Oregon and Washington. These impacts can lead to increased shoreline erosion, as they did during the 2015-16 El Niño event.

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