The current El Ni?o is now one of the strongest on record, new data shows, catapulting it into rare “super El Ni?o” territory, but forecasters believe that La Ni?a is likely to develop in the coming months.
One of the main ways scientists determine whether El Ni?o is present, and a key indicator of its strength, is through ocean surface temperatures. And from November to January, the temperature of the tropical Pacific Ocean where El Ni?o originates was 2 degrees Celsius warmer than normal, according to NOAA’s Climate Prediction center – a threshold that has only been breached six times on record. It means a very strong El Ni?o is ongoing.
But this so-called super El Ni?o’s strength won’t last long – it has reached its peak strength and is headed on a downward trend, said Michelle L’Heureux, a climate scientist with the Climate Prediction Center.
“We’re slightly past peak [strength] at this point,” L’Heureux told CNN.
Forecasters believe the switch could get totally flipped to La Ni?a – cooler than average conditions in the eastern tropical Pacific – as soon as summer, but more likely by fall, and issued a La Ni?a watch on Thursday.
El Ni?o influences weather around the globe, so its strength and demise will continue to have an impact on the weather we experience in the coming months.
The stronger an?El Ni?o gets, the more likely it is to influence the global weather over time. But its impact is measured on a seasonal timescale, and not in terms of individual weather events, L’Heureux explained.
El Ni?os have hallmark seasonal signs, particularly on winter in the US.
A warmer-than-average winter with less snow across the northern tier of the US is one of these signs. This exact scenario is unfolding this winter. Multiple states in the region experienced the warmest-ever December and an overall toasty January with paltry amounts of snow – a trend that’s continuing into February.
El Ni?o also manifests as a wetter-than-average winter for the southern tier of the US as it often points the storm-steering jet stream south.
A serious drought in parts of the South has largely been wiped out this winter by repeated bouts of rain from storm systems. And California was just deluged by back-to-back potent atmospheric river-fueled storms that unloaded record rainfall and hundreds of mudslides.
El Ni?o has been known to enhance atmospheric river events on the West Coast.
“It’s difficult to attribute any single weather system or series of them to El Ni?o. With that said, it seems probable that there were some links to El Ni?o [with California’s storms],” L’Heureux noted.
The additional source of heat from warmer water in the eastern Pacific Ocean can be especially impactful to weather patterns in the western portions of both Americas that border the Pacific.
The recent disastrous, deadly fires in Chile reflect the El Ni?o connection. The pattern is linked to decreased precipitation in the northern part of the country which contributed to extensive drought that left areas tinder-dry.
El Ni?o has also left its fingerprints on temperature and precipitation patterns in?several other continents, including South America, Africa, Australia and parts of Asia, according to L’Heureux.
But L’Heureux is careful to caution that not every extreme weather event can be attributed directly to El Ni?o in a warming world.
“El Ni?o impacts don’t occur in isolation anymore. There’s certainly a climate change component,” L’Heureux said.
Human-caused climate change is driving up global temperatures, leading to more frequent and intense extreme weather events.
La Ni?a watch issued
A La Ni?a watch is now in effect, meaning conditions are favorable for a La Ni?a to form within the next six months, according to a forecast released by the CPC Thursday.
The center is eyeing this transition to unfold during the summer months, with La Ni?a conditions increasingly likely to be in effect through the fall.
There is a 55% chance of La Ni?a to develop from June to August and a 77% chance from September to November, according to L’Heureux and the forecast.
This abrupt pattern flip is not unprecedented. Historically, strong El Ni?os are followed by La Ni?a conditions about 60% of the time, L’Heureux said.
Depending on when – or even if – La Ni?a materializes, this large-scale pattern flip could have significant implications for how the rest of the year’s weather plays out.
La Ni?as often produce the opposite weather patterns as El Ni?o, including a more active Atlantic hurricane season. La Ni?a conditions were in place for a portion of the most active Atlantic hurricane season on record: 2020.
A quicker switch to La Ni?a could mean more of an impact on the upcoming hurricane season, which begins in June and typically peaks in September – particularly if oceans stay exceptionally warm.
Last year’s Atlantic hurricane season?was unusually active amid record warm oceans, despite attempts by El Ni?o to tamp down activity.
CNN’s Rachel Ramirez and Brandon Miller contributed to this report