Hurricane researchers at Colorado State University are trying to temper expectations for a potentially record-breaking year, but they're not ready to wave the white flag and call a premature end to the season just yet.
On Tuesday, Dr. Phil Klotzbach, a hurricane expert at California State University, Tropical cyclone activity in the basin is expected to be near or below normal. At least until September 16th.
The basin remains at record low activity, with only a 10% chance of above normal activity in the coming weeks.
In fact, the lull in tropical activity from August 12 to September 3 marked the quietest period of tropical weather development in the past 56 years, and the basin is now beginning to lag behind key seasonal indicators of average.
As of September 4, the season has already produced seven named tropical storms, two hurricanes, and one major cyclone.
So far in 2024, the basin has seen five named storms, three hurricanes, and one major hurricane.
However, with limited activity expected over the next two weeks, production in the basin is unlikely to reach normal levels.
“So what has been holding back storms over the past few weeks? I think a big issue is the position of the monsoon trough over Africa,” Klotzbach told Fox Weather.
“We are seeing anomalous cooling in the Gulf of Guinea region that is associated with an Atlantic Niña trend (although it may not officially meet the definition). This is causing strong cross-equatorial (sea surface temperature) and sea level pressure gradients, which is pushing the monsoon trough too far north when looking for hurricane activity.”
What's happening in the tropics?
Forecasters point to at least four factors as contributing to the activity: the location of the monsoon trough over Africa, cold water in the eastern Atlantic, very high temperatures in the upper atmosphere, and an abundance of dry air around the eastern edge of the basin.
Computer models struggled to capture these deviations from the norm, which likely negated favorable features such as reduced vertical wind shear, near-record sea surface temperatures, a strengthening African monsoon, and the emergence of a La Niña phenomenon in the El Niño Southern Oscillation.
That being said, the only overarching question that remains is whether favorable conditions will return to the basin or is the season effectively over?
“I think it's too early to give up on this season,” Klotzbach said.
“The latest EPS ensemble is stronger on upcoming Atlantic tropical cyclone activity. I'll give you a two week forecast.“The current National Hurricane Center area over the Caribbean is under a watch as the hurricane enters the Gulf of Mexico. Additionally, a strong easterly surge is likely moving off Africa within about a week. It's too early to know what will happen with this system, but overall, conditions for hurricane intensification look pretty favorable at this time.”
This season could still reach normal levels of activity with 14 named storms, seven hurricanes, and three major hurricanes, but amounts significantly above what occurs in an average season seem unattainable.
It's important to remember that a normal season can have just as much of an impact as a busier than normal year.
The 2022 season was expected to be a near-normal one with 14 named storms, eight hurricanes, and two majors, but Hurricane Ian emerged, making it the third-costliest year on record.
In contrast, 2023 was considered a busier season than normal, with 20 named storms, but its impact on the U.S. was the least in the past decade.
Tropical activity declines in much of the world
In their latest report, the researchers did not mention that ocean surface temperatures are at record highs, yet activity around the world is at record lows.
In other words, the Atlantic is not simply experiencing a one-off year; the Indian and Pacific Ocean basins are experiencing widespread outages as well.
Tropical weather experts, including Klotzbach, have long suggested that there has been an overall decline in tropical cyclone activity worldwide, and particularly in the western Pacific, so an overall decrease in activity is not unprecedented.
“We looked at global tropical cyclone activity from 1990 to 2021 and found that there has been a significant decline in the number of hurricanes and ACEs worldwide, driven mainly by a significant downward trend in the western North Pacific.” The researchers said in their 2022 report.
But the report notes that cyclones that do occur are increasingly costly and intensifying rapidly.
It remains to be seen whether the dramatic decline in tropical cyclone activity around the world is a sign of fewer impacts in the coming years, or whether this was simply an unusual year.
The Atlantic, eastern and central Pacific hurricane season lasts until November 30, although basins such as the western Pacific can experience hurricane activity throughout the year.
