2024 hurricane season activity is expected to be above average
The combination of a weak El Nino and warm water temperatures could be ingredients for an active hurricane season in the Atlantic Basin.
Although the El Niño of 2023-2024 is not historic, water temperatures in many of Earth's vast oceans are still setting records, which has widespread implications.
During positive phases of El Niño and Southern Oscillation, or commonly referred to as ENSO, water temperatures in the world's largest ocean – the Pacific – are usually above average. However, over the past few months, all oceans have been in record territory.
According to monitoring data from the University of Maine's Climate Change Institute, global water temperatures are about 1.44 degrees Fahrenheit above average, with the North Atlantic Ocean hovering around 2 degrees Fahrenheit above average.
Global sea surface temperatures as of 5 March 2024. (University of Maine Climate Change Institute/Fox Weather)
The anomalies, or temperatures higher or lower than normal, were greater, but it was the extent of warm water that concerned scientists.
“Ocean surface temperatures in the tropical Pacific clearly reflect the El Niño phenomenon,” Celeste Saulo, Secretary-General of the World Meteorological Organization, said in a report. “But sea surface temperatures in other parts of the world have been persistently and unusually high over the past 10 months.” past”. statement. “The sea surface temperature in January 2024 was the highest on record for a January. This is worrying and cannot be explained by El Niño alone.”
Water temperatures in the North Atlantic have remained at record highs for more than a year, with the last time the world's basins were cooler than average collectively in 2011.
Hurricane season 2024: Here's what to look for in the tropics this year
North Atlantic sea surface temperatures as of early March 2024. (University of Maine Climate Change Institute/Fox Weather)
Impacts from warmer oceans
When water is heated, it expands. NASA estimates that between one-third and one-half of global sea surface rise is due to warming oceans.
This can lead to coral bleaching, melting ice sheets, fluctuations in the intensity of storm systems and changes to ecosystems.
Rapid changing water temperatures have been documented to stress coral reefs, causing mass bleaching and disease.
In 2023, the National Oceanic and Atmospheric Administration (NOAA) estimates that less than 22% of about 1,500 coral reefs will survive the warming waters around the Florida coast.
Just a two-degree change in temperature can cause corals to lose beneficial algae.
According to marine biologists, the bleached coral is not dead. However, it causes the ecosystem to be less resistant to diseases and storms.
A chart showing how climate change is affecting coral reefs. (NOAA)
A warm Atlantic Ocean doesn't always mean an uptick in hurricane activity
It is a common misconception that a warm Atlantic Ocean will produce above average hurricane activity. While warmer than average temperatures are certainly an important component, dry air levels and shear are also important factors in tornado formation.
There are many seasons in which warm water temperatures result in minimal or no tropical cyclone activity.
Historians only have to go back to August 2022, when no identified hurricanes formed. In 2013, a record low level of hurricanes was recorded during the satellite era.
This graph shows the amount of tropical cyclone activity, in terms of named storms and hurricanes, that occurs in the Atlantic Basin on each calendar day between May 1 and December 31. Specifically, it shows the number of hurricanes (yellow area) and combined storms and hurricanes (red area) that occur on each calendar day over a 100-year period. The graph is based on data from the 77-year period from 1944 to 2020 (starting at the beginning of the aircraft reconnaissance era) but normalized to 100 years. The official hurricane season for the Atlantic Basin runs from June 1 to November 30, but tropical cyclone activity sometimes occurs before and after these dates, respectively. The peak of the Atlantic hurricane season is September 10, with most activity occurring between mid-August and mid-October. (National Hurricane Center/NOAA)
Reanalysis of those periods found high levels of stability and a low amount of available moisture, two ingredients for hurricane formation.
The combination of declining El Niño and warming water temperatures in the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico has prepared the basin for a phase not seen before.
“So the weird temperature distribution across the Atlantic waters is going to affect the way the air flows across the Atlantic as well, and let's just say it's unpredictable in ways because that's a pattern we've never seen before,” Fox said. Hurricane Weather Specialist Brian Norcross. “So, when we get these patterns that are kind of off the charts, different from what we have, where we can compare them to last hurricane season, it's impossible to really put your finger on exactly how things are related.”
Effects of the La Niña phenomenon on hurricane season. (Fox Weather)
The strange state of the oceans hasn't stopped some forecasters from calling for extreme activity in 2024. Many of these predictions are made by the same people who predicted the winter of 2023-2024 would be one of the coldest in a long time — which is speculative. It couldn't be further from what already happened.
Meteorologists from Colorado State University, the National Oceanic and Atmospheric Administration (NOAA) and other reputable organizations analyze computer models, which take into account not only sea temperatures but also complex atmospheric patterns such as the Madden-Julian Oscillation, North Atlantic Oscillation and others.
CSU's hurricane forecast is scheduled to be released in April, and NOAA's forecast will be published in May.
