Recent forecasts indicate that El Niño will develop by August and remain strong through the fall peak of the hurricane season. This could lead to a collision of two powerful factors – warm Atlantic Ocean water and El Niño – that could make or break the Atlantic hurricane season.
Hurricane ingredients
In general, hurricanes are formed and strengthened when a tropical low-pressure system collides with an environment that includes high upper-ocean temperatures, atmospheric moisture, instability, and weak vertical wind shear. Warm ocean temperatures provide the energy for hurricane development, and vertical wind shear disrupts hurricane growth.
Tropical Atlantic Ocean temperatures have been unusually high during the most active Atlantic hurricane seasons in recent years. The 2020 Atlantic hurricane season produced a record 30 named tropical cyclones, while the 2005 Atlantic hurricane season produced 28 named storms, a record 15 of which were hurricanes, including Katrina.
Winds and El Niño
When the tropical east-central Pacific Ocean is unusually warm, El Niño can form. During El Niño events, high upper-ocean temperatures alter the vertical and east-west atmospheric circulation in the tropics. This initiates a coupling, affecting the east-west winds in the upper atmosphere throughout the tropics, which ultimately leads to a stronger vertical wind shear in the Atlantic basin. This wind shear can suppress hurricanes.
Tug of war
My research and the work of other atmospheric scientists has shown that the warm Atlantic and warm tropical Pacific tend to counteract each other, resulting in a near average Atlantic hurricane season. This year, however, they are in conflict and are likely to have a countervailing influence on decisive conditions that could make or break the Atlantic hurricane season. The result could be good news for the Caribbean and Atlantic coasts: hurricane season is almost average. But forecasters warn that this hurricane forecast depends on El Niño.
Conclusions
The 2023 Atlantic hurricane season promises to be one of the most unusual in recent years. A strong El Niño and warm Atlantic Ocean water could collide and make or break the Atlantic hurricane season. Although the warm Atlantic and warm tropical Pacific tend to oppose each other, they are in conflict this year. The result could be good news for the Caribbean and Atlantic coasts: hurricane season is almost average. However, forecasters warn that this hurricane forecast depends on El Niño.
