From The Washington Post:
The surprising reason there have been no Atlantic hurricanes this year
El Niño isn’t the only factor. Another force could be contributing to fewer storms and a later peak in the season.
The hurricane-free conditions thus far may be giving some coastal residents in the Gulf and eastern United States a reprieve, but they are also fueling drought across the Caribbean.
A record-breaking El Niño in the Pacific Ocean has created harsh winds that have swept into the Atlantic, preventing storms from growing. Dry air, occasionally coinciding with dust from Africa’s Sahara Desert, has choked off storms from the moisture they require to become more powerful.
But a third limiting factor, linked to the planet’s warming trend, may come as a surprise — and be responsible for shifting the peak of hurricane season later into the year.
In the Atlantic, the atmosphere has been more stable than normal.
“At its most basic level, atmospheric stability is the tendency for air to want to rise or sink,” said hurricane specialist Michael Lowry, who described it as one of the six key ingredients of hurricane formation identified by hurricane researcher William Gray in the late 1960s.
“If any one factor is off-kilter, it can torpedo the usual spate of activity around its sharp peak in August, September and October,” said Lowry.
Increasing atmospheric stability in the tropical Atlantic may be connected to a changing climate. Temperatures have been rising at different rates in the troposphere, which is the lowest layer of the atmosphere — and the one in which people live.
As the tropical Atlantic has warmed during recent decades, more water has evaporated into the atmosphere. Thunderstorms act like elevators, carrying that extra warmth and moisture high into the troposphere. When the moisture condenses into clouds, it releases heat, helping the upper troposphere warm faster than air closer to the ground.
And that matters for hurricanes.
If the upper troposphere warms faster than the air below, the atmosphere becomes more stable because the temperature difference between the lower and upper atmosphere shrinks. That makes it harder for air to keep rising and thunderstorms to organize into tropical storms and hurricanes.
Since the start of this year’s hurricane season, that atmospheric temperature difference in the tropical Atlantic Ocean has been second smallest on record, with records dating back to 1940.
And, relatedly, there haven’t been any hurricanes yet.
But this uneven atmospheric warming may also contribute to “a kind of whiplash hurricane season,” said Lowry.
Historically, the peak of hurricane season is Sept. 10.
But if it’s taking the upper troposphere longer to cool off each fall, Lowry said that it could be contributing to a delayed hurricane season peak.
“The relative hurricane season peak has been happening later on average over the past decade,” Lowry said, sharing data that showed how it was pushing more into October and November.
“The big question is whether this is a short-term blip or a longer-term trend that could be tied to increasing stability,” said Lowry, adding that it was still an active area of research.
The idea that increasing atmospheric stability could contribute to fewer hurricanes overall is not new. The theory was investigated in academic research articles nearly two decades ago and Lowry and other researchers explored it following a lull in hurricane activity during 2024.
Meteorologist Andy Hazelton described the stability trend as “an issue that’s become more apparent since around 2010 or so,” sharing a view similar to Lowry that it’s linked to hurricane seasons that feature more activity late in the season rather than early.
“If this is a robust change over time, it could have implications for tropical cyclone tracks and risk,“ Hazelton said.
If the hurricane season peak shifts later, it could become more challenging for hurricanes to hit the U.S. East Coast. That’s because by October, the jet stream grows stronger and can blow storms out to sea.
“Not sure that the sample is big enough yet to say it’s definitively a ‘new normal’ but it’s pretty compelling,” said Hazelton.
