A rare atmospheric phenomenon developing in the Atlantic Ocean, known as an Atlantic Niña, is expected to help temper the current hurricane season. This cooling trend in sea-surface temperatures contrasts with a powerful El Niño event that has been strengthening in the Pacific Ocean.
Meteorologists are observing the emergence of an Atlantic Niña, characterized by an unusual cooling of sea-surface temperatures in the equatorial Atlantic. This condition can create an environment less conducive to hurricane development. According to Accuweather meteorologist Alan Reppert, an Atlantic Niña typically leads to reduced tropical activity in the Atlantic season, fostering a more hostile environment for tropical storms.
The developing Atlantic Niña has resulted in sea temperatures dropping between 2 to 5 degrees Fahrenheit below average. If this cooling persists, it would mark only the sixth occurrence of an Atlantic Niña in the last 40 years of recorded data, according to analysis from Severe Weather Europe.
In contrast, a significant El Niño has been warming ocean temperatures in the Pacific since June and is projected to be the most substantial one in at least 150 years, as reported by Nature. Peak Pacific Ocean temperatures are currently 3 to 4 degrees Fahrenheit above normal, based on data from the National Oceanic and Atmospheric Administration.
Studies suggest that Atlantic Niña events are associated with approximately 50% fewer tropical cyclones than average, including a reduction in storms that make landfall in the United States. Despite this mitigating factor, forecasters anticipate a moderately active storm season.
Reppert forecasts between 11 and 16 named storms, with 4 to 7 hurricanes and 2 to 4 major hurricanes. Of these, three to five are expected to impact the U.S. The eastern Gulf of Mexico coastline and the coastal regions of North and South Carolina are identified as areas with the highest risk for storm impacts.
While the Atlantic Niña is expected to weaken the overall storm season, experts caution that a single significant storm can still define a season. "The El Niño typically has a greater impact on the tropical Atlantic season than Atlantic Nina," Reppert added. Current projections indicate a relatively quiet period over the next few weeks with limited development potential, particularly for the U.S. Northeast coastline. However, the formation and trajectory of any storm can lead to a significant season, even with just one powerful event impacting a populated area.