The Atlantic hurricane season is experiencing record quietude this year, a phenomenon largely attributed to a strong El Niño that is actively suppressing storm development. As of recent reports, no Atlantic hurricanes have formed, and none are anticipated in the immediate future, despite this period typically being the peak of the season.
This year's season has seen only five relatively weak and brief tropical storms. According to Nick Novella, a meteorologist at the government's Weather Prediction Center, the period without a storm reaching hurricane strength (64 mph or 103 kph) is a record in the satellite era, which began in the 1950s. While earlier periods before 1950 saw some late-starting seasons, meteorologists consider those records less reliable due to incomplete ocean monitoring.
Overall hurricane activity, measured by storm count, strength, and duration, is also at a post-1950 record low. Storm activity in the Atlantic is currently only 7% of the normal for this time of year, according to Colorado State University hurricane expert Phil Klotzbach. However, experts, including those cited by The Associated Press, emphasize that complacency is unwarranted, as a single storm, even during an El Niño year, can be catastrophic, citing the example of Hurricane Andrew in 1992, which formed late but caused significant devastation.
El Niño's Impact on Storm Formation
Several atmospheric scientists describe the Atlantic as exceptionally inhospitable to tropical cyclone formation. Kristen Corbosiero, an atmospheric science professor at the University at Albany, explained that developing storms face a "triple whammy" of factors: disruptive upper-level winds, dry air, and downward-pushing winds that inhibit growth. These conditions are classic impacts of El Niño, a natural warming of the equatorial Pacific that alters global weather patterns.
Klotzbach characterized the El Niño's effect on the Atlantic as "hammering," noting the absence of anything close to a hurricane. A primary driver is record-strong wind shear, where conflicting wind directions at different altitudes effectively "tear apart" developing storm systems. Corbosiero stated that in the typical storm formation zones between Africa and the Caribbean, wind shear is approximately 45 mph stronger than a tropical cyclone can withstand, an "unheard of" level.
While the Gulf of Mexico has seen less extreme wind shear, and storms in this region often develop later in the season, experts warn that strong storms could still emerge there. Other contributing factors include dry air, African dust that hinders development, and a high-pressure system in the Atlantic pushing air downward, all of which are consistent with El Niño's influence.
These suppressive factors are present despite unusually warm ocean waters globally, which typically fuel storm development. This highlights the potency of El Niño in overriding warmer sea surface temperatures. Meteorologist Kerry Emanuel noted that the atmosphere has warmed faster than the ocean in this El Niño, and the temperature difference between air and water is crucial for hurricane formation. Hurricanes draw power from heat transfer from ocean to air; a larger temperature difference results in less storm activity.
While the Atlantic waters are lagging behind the atmosphere in responding to El Niño, the persistent warm water may contribute to an active season in the following year, once the El Niño begins to wane.
Contrasting Pacific Activity
In contrast to the quiet Atlantic, El Niño typically intensifies tropical cyclone activity in the Pacific Ocean by providing moist air and low wind shear. This year, the eastern Pacific has experienced nearly double its normal storm activity, with hurricanes lasting longer than usual. The central Pacific has seen approximately 40% more activity than normal.
Collectively, the eastern and central Pacific have produced 36 named storms, compared to the five small tropical storms observed in the Atlantic. Hawaii has been impacted twice, as El Niño tends to steer storms further west. Forecasters had predicted a subdued Atlantic hurricane season based on known El Niño effects, but the extent of this year's quietude has surprised many observers, including hurricane expert Brian McNoldy.