What’s a super El Niño? What the rare weather event could mean for Central PA
A rare “super El Niño” is increasingly likely to occur this summer or fall, meteorologists say. But despite the name, the event won’t necessarily bring about extreme weather.
“Super El Niño, that’s when the waters there in the equatorial eastern Pacific get to 2 degrees Celsius or greater above historical averages,” Accuweather long range meteorologist Alex DaSilva said.
The weather event has only happened seven times since the 1950s, meaning there is little precedent for what a super El Niño might look like in Central Pennsylvania.
DaSilva explained that super El Niños typically occur toward the tail end of summer. The most recent one to occur, between 2015 and 2016, brought about slightly higher-than-average temperatures and precipitation. The one prior, between 1997 and 1998, saw cooler temperatures and average precipitation.
“The sample size basically isn’t great enough for us to really pin down a perfect correlation with what we can expect,” DaSilva said.
As of mid-April, the likelihood of a super El Niño currently rests around 15%, DaSilva said, and that likelihood has crept up in recent weeks. The National Oceanic and Atmospheric Administration pins the likelihood around 25%.
Forecasters say a regular El Niño — a warming of Pacific Ocean temperatures coupled with weakened or reversed easterly winds — is likely to occur, regardless. La Niña, by contrast, is a cooling of Pacific Ocean temperatures coupled with stronger winds.
El Niño tends to bring about warmer summer temperatures and dry spells, with strong, intermittent storms. DaSilva said good precipitation in recent months might make weathering dry spells easier.
How a super El Niño would affect Central Pennsylvania could depend on factors besides Pacific temperatures, DaSilva noted. Leftover snow in Canada could cool temperatures locally, and Atlantic temperatures could play into rainfall.
