Climate phenomenon could significantly impact approaching hurricane season
El Niño-southern oscillation-neutral conditions are forecast to persist through the summer of 2025, and while the cycle may not play a major role on day-to-day weather, it could be a significant factor in determining the intensity of the approaching hurricane season.
This most recent forecast from the National Weather Service’s Climate Prediction Center issued on May 8 suggests that there is a 74% chance of El Niño-southern oscillation-neutral conditions from June through August. There is also a greater than 50% chance these conditions continue through October.
The El Niño-southern oscillation cycle, otherwise known as the ENSO cycle, is a recurring climate pattern pertaining to changes in the water temperatures in the central and eastern tropical Pacific Ocean, noted the weather service.
Over time, the sea surface temperatures tend to either get warmer or cooler.
El Niño-southern oscillation-neutral conditions are present when water temperatures are normal, neither below or above-average; La Niña is the cold phase of this cycle and El Niño is the warm phase.
“There’s other things that are more important, other parameters you can look at and other indices that carry more weight in the summer months, like late spring, summer, maybe into early Fall,” Dave Dombek, a senior meteorologist with AccuWeather, said of the El Niño-southern oscillation cycle during the summer. “And especially if it’s neutral then it really is like kind of right in the middle of the scale there, so it really would not really have any bearing at all.”
While the cycle may not play a major role on the general weather and temperatures, it could influence the hurricane season.
During El Niño-southern oscillation-neutral conditions, the severe weather season “behaves a little bit more what you would consider average.”
And while El Niño-southern oscillation-neutral conditions are currently expected to persist through the summer, the probability of it remaining through the autumn is just over 50%.
As of May 8, the Climate Prediction Center already forecasts a 41% chance of La Niña returning sometime between November and January.
Keep in mind that, as stated by the Climate Prediction Center, “uncertainty increases at longer time horizons,” and these probabilities could change.
Should the forecast change and La Niña takes charge in the fall, Dombek says the conditions could cause heightened tropical activity in the Pacific Ocean and Atlantic Basin. As a result, more storms could develop and hurricanes could be strengthened. Moreover, the hurricane season as a whole could be extended into November, potentially even December.
On the other hand, during El Niño years there are typically fewer than average named storms in the Atlantic basin.
“Basically, something to watch is as you get into like August, September, if that time if we go from neutral and we’re transitioning into a La Niña — even if its a weak La Niña at that time — if the trend is going toward La Niña then that’s something to watch,” Dombek noted.
If La Niña does resurge in the winter, U.S. residents can expect temperatures to generally be warmer than usual in the South and colder than normal in the North. Additionally, storms in the winter months could take a more northerly track.