A powerful El Niño is helping produce two very different hurricane seasons on opposite sides of the Americas, with the Pacific running unusually active while the Atlantic has remained comparatively quiet, according to University of South Florida professor Patrick Rafter.
Rafter, an assistant professor with the university’s College of Marine Science, joined FOX Weather meteorologist Bob Van Dillen to discuss the contrast between the two basins and what the current El Niño pattern could mean as the calendar moves deeper into fall and eventually toward winter.
Van Dillen described the Pacific as a nearly nonstop “caravan” of tropical systems moving from east to west this season, while noting that the Atlantic had produced several named storms without recording a hurricane at the time of the discussion.
For Rafter, that split is increasingly looking like a classic response to a strong El Niño, with conditions favoring tropical development in the Pacific while making it more difficult for storms to organize across much of the Atlantic.
Pacific Has Been Extremely Active
Rafter said the level of activity in the Pacific was largely consistent with what forecasters had expected once a very strong El Niño developed.
“The Pacific has been crazy active this year,” he told Van Dillen.
That activity has repeatedly sent tropical systems westward toward the central Pacific, which has kept Hawaii more involved in the tropical conversation than it might be during a quieter year.
Rafter said residents in Hawaii should continue watching the basin carefully through the remainder of the season, particularly because the islands have already dealt with substantial rainfall and saturated ground.
Even a weakening tropical system can create problems when the soil is already wet, because additional moisture can increase the risk of flooding and runoff, especially along the steep terrain of the islands.
Van Dillen also pointed out that the mountainous landscape of the Big Island can enhance rainfall when moisture-rich trade winds are forced upward, making the amount of rain just as important as the strength of any approaching storm.
That is an important distinction in tropical weather, because a system does not need to arrive as a strong hurricane to create meaningful impacts.
Why Pacific Storms Can Weaken
Van Dillen asked Rafter why some of the Pacific systems appeared to be struggling to maintain their strength as they moved farther west and north.
Rafter said there are several possible factors, including the cooler wake left behind by previous tropical cyclones.
Strong storms churn the upper ocean and mix cooler water toward the surface, which can temporarily reduce the warm-water energy available to systems that follow along a similar path.
“There is the general understanding that when a hurricane moves through an ocean basin, it leaves behind a wake of cooler waters,” Rafter explained.
He also pointed to stronger upper-level wind shear farther north of Hawaii as another possible reason tropical systems could weaken before reaching the islands.
Neither process guarantees that a storm will fall apart, but both can make the environment increasingly hostile as a system moves away from the most favorable part of the basin.
Atlantic Struggles With Wind Shear
The Atlantic has presented almost the opposite story.
Rafter said the region off northwestern Africa, which normally becomes one of the most important breeding grounds for late-summer and early-fall hurricanes, has been dealing with strong upper-level wind shear.
That shear can disrupt the vertical structure of developing tropical systems, preventing thunderstorms from staying organized around a central circulation.
Rafter said this was one reason he had previously suggested watching areas farther west, including the Gulf of Mexico and the subtropical Atlantic, where conditions could occasionally become more favorable.
“If the water is warm enough and the upper-level winds are kind of mellow, we might be seeing some storms forming there,” he said.
Van Dillen noted that one disturbance southeast of Bermuda fit that general idea, since it was developing farther north than the traditional tropical waves coming directly off Africa.
Rafter cautioned that not every forecast idea works out, but said the placement of tropical development this year made sense from a basic climate perspective.
The main lesson is that a quiet Atlantic does not mean the entire basin is shut down. It means the most favorable zones for development may be displaced from their usual locations.
Saharan Dust Adds Another Complication
Van Dillen also showed Rafter a large plume of Saharan dust moving off Africa, something he described as unusual for this late in the season.
Rafter was struck by its size and said many people probably underestimate how much dust from North Africa can travel all the way across the Atlantic and into the United States.
He recalled collecting air samples while attending college in Florida and once finding a filter coated in a golden-colored layer, only to learn from a professor that it was African dust.
Large dust outbreaks can contribute to a more stable and dry atmosphere over portions of the Atlantic, adding another challenge for tropical systems trying to form or strengthen.
Van Dillen said the plume looked more like something he would expect during July or early August than in the second half of September.
That does not mean Saharan dust is solely responsible for the slow Atlantic season, but alongside wind shear it provides another piece of an environment that has frequently worked against tropical development.
Rafter Sees a Strong El Niño Signal
Looking beyond hurricane season, Rafter said the current El Niño is strong enough that he has more confidence than usual in some of the typical seasonal effects associated with the pattern.
He said he normally avoids making overly direct connections between El Niño and specific regional weather outcomes, because individual seasons can vary widely even under the same broad climate pattern.
This year, however, he believes the signal has been unusually clear.
“This El Niño is just so huge,” Rafter said.
He pointed to the active Pacific and quiet Atlantic as examples of what he called a fairly standard El Niño response, and said that consistency gives him more confidence in what may follow through fall and winter.
As the pattern continues, Rafter expects the jet stream to favor a more southerly track across the United States.
That would generally support drier and possibly somewhat warmer conditions across the northern part of the country, while bringing more frequent rain chances to the southern United States.
Southern States Could Turn Wetter
Rafter said the southern half of the country could become “much rainier” as the El Niño-influenced jet stream becomes more established.
Van Dillen noted that this could eventually help areas such as central Florida, where drought conditions have been a concern.
Rafter also mentioned that individual upper-level systems can still provide additional rainfall outside the direct El Niño signal, meaning not every storm or wet period should automatically be blamed on the larger climate pattern.
That distinction matters because El Niño influences the background setup rather than controlling every weather system by itself.
Still, if the stronger El Niño pattern continues behaving as expected, the southern tier may see more frequent storm systems as fall progresses and winter approaches.
For parts of the South that have dealt with persistent dryness, that could eventually become beneficial, although too much rain arriving too quickly would introduce a different set of problems.
Different Oceans, Same Climate Driver
The conversation between Van Dillen and Rafter highlighted how one large-scale climate pattern can produce very different outcomes depending on the ocean basin.
In the Pacific, warmer waters and a more favorable tropical environment have supported frequent storms, while the Atlantic has repeatedly faced wind shear and other hostile conditions.
Rafter believes the contrast is one of the clearest signs yet that the current El Niño is exerting a strong influence.
The tropical season is not over, and neither Rafter nor Van Dillen suggested that the Atlantic can be ignored simply because it has been quieter than usual.
Instead, the broader picture is that the places most favorable for storms have shifted, while the same El Niño that has shaped hurricane season may continue influencing the jet stream and rainfall patterns well beyond the tropics.
For now, that means continued attention on the Pacific, a watchful eye on less traditional development zones in the Atlantic, and growing interest in how the pattern carries into the colder months ahead.
Gary’s love for adventure and preparedness stems from his background as a former Army medic. Having served in remote locations around the world, he knows the importance of being ready for any situation, whether in the wilderness or urban environments. Gary’s practical medical expertise blends with his passion for outdoor survival, making him an expert in both emergency medical care and rugged, off-the-grid living. He writes to equip readers with the skills needed to stay safe and resilient in any scenario.
