This Atlantic hurricane season could look like 2020, as La Niña and warmer oceans lead to more intense storms

The 2024 Atlantic hurricane season begins June 1, and forecasters are anticipating an exceptionally active season.

if National Hurricane Center early forecasts, released May 23, is right: the North Atlantic could see 17 to 25 named storms, eight to 13 hurricanes, and four to seven major hurricanes by the end of November. This is the largest number of named storms in any NOAA preseason forecast.

Other predictions were for this season Just as intense. Colorado State University Early Predictions, released in April, predicted an average of 23 named storms, 11 hurricanes and five major hurricanes. the European Center for Medium-Range Weather Forecasts It forecasts 21 named storms.

Colorado is also expecting a whopping 210 Accumulated hurricane energy units for 2024, and the National Oceanic and Atmospheric Administration (NOAA) forecasts the second-highest ACE rate ever. Cumulative hurricane energy is a score for how active a given season is by combining the intensity and duration of all storms that occur during a given season. Anything over 103 is considered above normal.

This forecast puts the 2024 season on par with 2020, when so many tropical cyclones formed in the Atlantic that they exhausted renewable energy resources. The usual list of storm names: 30 named storms, 13 hurricanes, and six major hurricanes were recorded that year, combining for 245 accumulated hurricane energy units.

So, what makes the Atlantic hurricane season so active?

I am Climate scientist Who worked on seasonal hurricane forecasts and studied how climate change affects our ability to predict hurricanes. Forecasters and climate scientists look for two main clues when assessing risks from upcoming hurricane seasons in the Atlantic: the warm tropical Atlantic and the cold tropical eastern Pacific.

Warm Atlantic waters can fuel hurricanes

During the summer, the temperature of the Atlantic Ocean rises, resulting in generally favorable conditions for hurricane formation.

Warm surface waters of the oceans –About 79 degrees Fahrenheit (26°C) and above – provides increased thermal energy, or latent heat, which is released through evaporation. This latent heat causes upward motion, which helps form clusters of storm clouds and vortex that can bring these storms together to form rain bands around the vortex.

Ocean temperatures in 2024 are a big reason why forecasters are warning of a busy hurricane season.

The sea surface temperature in the North Atlantic was Breaking heat records For most of last year, temperatures started out really hot and remain that way It is expected to remain high through the summer. Globally, ocean temperatures were It rises as the planet warms.

The long-term temperature pattern known as Atlantic Multidecadal Oscillation (AMO)., also comes his turn. The surface of the Atlantic Ocean in summer can be warmer or cooler than normal for several seasons in a row, sometimes for decades.

Warm phases of the AMO mean more energy for hurricanes, while cool phases help suppress hurricane activity by increasing the strength of the trade winds and vertical wind shear. The Atlantic Ocean has been in a warm AMO phase since 1995, which coincided with… Very active Atlantic era Hurricane seasons.

How the Pacific Ocean can interfere with Atlantic storms

It may seem strange to look to the Pacific Ocean for clues about Atlantic hurricanes, but Pacific temperatures also play an important role in the winds that can influence hurricanes.

As in the Atlantic Ocean, water temperatures in the eastern Pacific Ocean oscillate between warm and cold phases, but on shorter timescales. Scientists call this El Niño Southern Oscillation or ENSO. The warm phases are known as El Niño; The cold phases are called La Niña.

La Niña Promotes upward movement of air Over the Atlantic Ocean, feeding deeper rain clouds and heavier rain.

The effects of La Niña also weaken the trade winds, reducing vertical wind shear. Vertical wind shearThe difference in wind strength and direction between the upper atmosphere and the atmosphere near Earth’s surface makes it difficult for hurricanes to form and can break up the storm vortex.

In contrast, El Niño promotes stronger trade winds, which increases wind shear. It also focuses on upward motion and precipitation in the Pacific Ocean, which results in downward motion that enhances mild weather over the Atlantic Ocean.

The El Niño phenomenon was strong during the winter of 2023-2024, but this was expected to happen Dissipates by JuneWhich means less wind shear to control hurricanes. La Niña conditions Probably by late summer.

ENSO may be located in a transition phase How early in the season Tropical storms form, and when do they occur? The rapid transition to La Niña may indicate an earlier start to the season as well as a longer season, as La Niña – combined with a warm Atlantic Ocean – maintains a hurricane-friendly environment earlier and longer into the year.

This ocean tag team controls hurricane activity

Atlantic and eastern Pacific Ocean temperatures Together to control Atlantic hurricane activity. This is like jumping in a bounce house or on a trampoline. You can get a good bounce when you jump alone but reach much greater heights when you have one or two other people jumping with you.

When the eastern Pacific Ocean is in its cold phase (La Niña) and the waters of the Atlantic Ocean are warm, Atlantic hurricane activity tends to be more frequent, with a greater likelihood of more intense and longer-lived storms.

The record hurricane season of 2020 had the influence of both La Niña and hurricane events Atlantic Ocean temperatures riseThis is what forecasters expect to see in 2024.

It is also important to remember that storms can also intensify under somewhat unfavorable environments as long as there is a warm ocean to fuel them. For example, the storm that eventually became Hurricane Dorian in 2019 The hurricane was surrounded by dry air as it headed toward the Caribbean, but it quickly intensified into a very destructive Category 5 hurricane over the Bahamas.

This article has been updated as NOAA officials described the forecast as the largest number of storms ever forecast.

Jordan Jones He is a postdoctoral research fellow in climate and extreme weather at Purdue University.

This article was republished from Conversation Under Creative Commons license. Read the Original article.