El Niño may return during the 2017 hurricane season

By Johnathan Belles for Weather.com

In a statement on Feb. 9, the Climate Prediction Center announced the end of La Niña, the counterpart to El Niño that changes global weather patterns. These oscillations occur naturally with periods of 2 to 7 years with varying predictable effects around the globe – including hurricane activity.

With La Niña's end, sea temperatures have steadily warmed in the equatorial region of the central and eastern Pacific, and we're now in the neutral phase of the oscillation. As shown below, models currently suggest we'll be in the neutral category through the spring and into the summer months (June-July-August, or JJA), but after that, sea temperatures could be warm enough for El Niño conditions to take over.

More from Weather.com: When Do Temperatures Typically Warm Up?

In the heart of hurricane season – August, September and October (ASO) – the chance for El Niño climbs over 50 percent, according to the International Research Institute for Climate and Society (IRI) forecast. NOAA-CPC also forecasts about a 50 percent chance of El Niño developing sometime September through November.

However, El Niño/La Niña model forecasts this time of year are very uncertain, as NOAA-CPC cautioned in a blog. That is because spring is a transitional time of year, which makes it difficult to forecast a change to a new phase.

RELATED: 15 of the deadliest American hurricanes ever

15 of the deadliest American hurricanes ever
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15 of the deadliest American hurricanes ever

Hurricane Hugo, 1989: 21 deaths

Hurricane Hugo made landfall as a Category 4 storm in South Carolina. It caused 21 deaths in the US and resulted in $7.1 billion of damage. At the time, it was the costliest storm in US history.

Photo courtesy: Getty

Tropical Storm Allison, 2001: 41 deaths

While not an official hurricane, Allison clocks in as the costliest and deadliest tropical storm in US history, causing 41 deaths and costing more than $5 billion in damage. The storm started over the Gulf of Mexico near Texas, then traveled east, causing floods like the one pictured here in Houston, Texas.

Photo courtesy: NOAA

Hurricane Irene, 2011: 56 deaths

Hurricane Irene, the first storm to hit the US since Ike three years earlier, made landfall in North Carolina as a Category 1 storm. The storm eventually made its way up to New York City, bringing flooding -- like the kind pictured here in Puerto Rico -- and causing $7.3 billion in damage overall.

Photo courtesy: AP

Hurricane Floyd, 1999: 57 deaths

Hurricane Floyd was a catastrophic storm because of the rain it brought along. The rain caused extreme flooding from North Carolina on up as the Category 2 storm traveled up the East Coast.

Photo courtesy: NOAA

Great Atlantic Hurricane, 1944: 64 deaths

The Great Atlantic Hurricane of 1944 was also devastating to New England, with 64 deaths and more than $100 million in damage. The storm was a Category 3 as it sped up the coast, hitting the Carolinas, Rhode Island, and Long Island before downgrading to a Category 2 in Maine.

Photo courtesy: NOAA

Hurricane Agnes, 1972: 122 deaths

Hurricane Agnes, as seen in this image made it all the way inland to Pennsylvania. Although it was only a Category 1 storm (with winds from 74-95 mph), it still caused 122 deaths and caused $2.1 billion in damage.

Photo courtesy: NOAA

Hurricane Ike, 2008: 195 deaths

The third costliest storm in US history, with $29.5 billion in damage, occurred in September 2008. Starting off the west coast of Africa, Hurricane Ike made its way over the Caribbean and into the Gulf, making US landfall in Texas as a Category 2 storm

Photo courtesy: Reuters

Hurricane Camille, 1969: 256 deaths

Hurricane Camille formed in the Gulf of Mexico and hit Mississippi as a Category 5 storm. Camille caused more than 256 deaths and clocks in as the second most intense hurricane to hit the US.

Photo courtesy: NOAA

New England, 1938: 256 deaths

Nicknamed "Long Island Express," the storm hit Puerto Rico as a Category 5 storm before charging north and hitting Long Island, New York and Connecticut as a Category 3 hurricane. The storm was responsible for more than 256 deaths.

Photo courtesy: NOAA

Hurricane Sandy, 2012: 285 deaths

With $71.4 billion in damage, Hurricane Sandy was the second costliest hurricane in US history. The Category 1 storm pummeled New York City, flooding the city's transportation systems and leaving thousands of homes destroyed.

It's looking more and more like Hurricane Joaquin won't make landfall in the US and join the list of most horrific storms in US history.

Photo courtesy: AP

Hurricane Audrey, 1957: 416 deaths

The U.S. started naming storms with women's names starting in 1953. Hurricane Audrey, the first storm of the 1957 hurricane season was the deadliest of the 1950s. It originated in the Gulf of Mexico, making landfall in Texas as a Category 4 storm. This image of the storm shows just how far hurricane imaging has come.

Photo courtesy: NOAA

Atlantic-Gulf, 1919: 600 to 900 deaths

This Category 4 storm swept into the Gulf of Mexico right under Key West, Florida(pictured), landing as a Category 3 storm in Corpus Christi, Texas. Anywhere from 600 to 900 people died in that storm.

Hurricane Katrina, 2005: 1,200 deaths

Hurricane Katrina is arguably the most notorious storm of the 21st century. The storm made landfall as a Category 5 near Miami before striking Louisiana as a Category 3 storm. Katrina was the third deadliest, and costliest hurricane in U.S. history with more than 1,200 deaths and $108 billion in damage.

Photo courtesy: Reuters

San Felipe Okeechobee, 1928: 2,500 deaths

This hurricane was the second deadliest in US history, with more than 2,500 deaths. The Category 4 storm made landfall in Palm Beach on September 10, 1928. Puerto Rico got hit hard as well, with winds at 144 mph.

Photo courtesy: NOAA

Galveston, Texas in 1900: 8,000 to 12,000 deaths

The deadliest hurricane in US history happened at the turn of the 20th century. The Category 4 of 5 hurricane -- with winds anywhere from 130-156 mph -- made landfall in Galveston, Texas (pictured), then headed north through the Great Plains. Anywhere from 8,000 to 12,000 people died in the storm.

Photo courtesy: Creative Commons


El Niño is defined as a season-long, or longer, warming of the eastern central Pacific waters close to the Equator by at least 0.5 degrees Celsius.

La Niña, and its counterpart warm phase El Niño, sometimes have major effects on the Atlantic hurricane season.

These effects are generally predictable, but not all El Niños are created equal, especially when it comes to the atmosphere. El Niño, as mentioned before, is actually a change in the ocean, not a straightforward atmospheric phenomenon.

The ocean and our atmosphere respond to each other in a loose relationship, and that relationship can result in slightly different effects from one El Niño to the next. For example, last year's strong El Niño failed to result in significant rainfall across Southern California, where it's typically expected in the winter during that phase.

More from Weather.com: Does a Warm Winter Lead to an Early Severe Peak?

History tells us that most El Niños inhibit hurricane growth through a couple of different ways.

Due to the warmer waters in the eastern Pacific, air rises above that water just like it would over a warm bowl of soup. That air cannot just go out to space. "What goes up must come back down" is a good way to explain what happens in parts of the Caribbean and western Atlantic. That air cools and descends on the northern side of Central America, stunting thunderstorm growth and stabilizing the weather in the region.

The winds that cross Central America are faster than they would be without El Niño. This enhanced wind takes the tops of the tropical clouds eastward faster than at the surface, which limits vertical thunderstorm growth.

More from Weather.com: Arctic Sea Ice at a Record Low; What Happens When It All Melts?

The low-level trade winds are also enhanced. These winds blow toward the west, pushing showers and storms westward faster than usual. This, combined with enhanced upper-level winds, tilts storms eastward, further hampering storm growth.

These effects aggregate into a less-active hurricane season, but this is what typically occurs, rather than a hard rule.

It's too early to know whether the latter half of the 2017 hurricane season will be impacted by any developing El Niño. After all, odds are still 50/50 as to whether it will develop or not.

Also unknown is how much of the aforementioned atmospheric response would occur before the end of the season even if El Niño did develop. In the months ahead, we should have a clearer picture of the ultimate outcome.

Hurricane season in the Atlantic Basin runs from June 1 to Nov. 30, but tropical cyclones – including hurricanes and tropical storms – can occur any time of the year.

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