Colorado State University hurricane researchers are predicting an extremely active Atlantic hurricane season. Record warm tropical and eastern subtropical Atlantic sea surface temperatures are a primary factor driving this.
Forecasters explain the situation as follows:
When waters in the eastern and central tropical and subtropical Atlantic are much warmer than normal in the spring, it tends to force a weaker subtropical high and associated weaker winds blowing across the tropical Atlantic. These conditions will likely lead to a continuation of well above-average water temperatures in the tropical Atlantic for the peak of the 2024 Atlantic hurricane season. A very warm Atlantic favors an above-average season, since a hurricane’s fuel source is warm ocean water. In addition, a warm Atlantic leads to lower atmospheric pressure and a more unstable atmosphere. Both conditions favor hurricanes.
While the tropical Pacific is currently characterized by El Niño conditions, these are likely to transition to La Niña conditions by the peak of the Atlantic hurricane season from August to October. La Niña tends to decrease upper-level westerly winds across the Caribbean into the tropical Atlantic. These decreased upper-level winds result in reduced vertical wind shear, favoring Atlantic hurricane formation and intensification.
Given the combined hurricane-favorable signals of an extremely warm Atlantic and a likely developing La Niña, the forecast team has higher-than-normal confidence for an April outlook that the 2024 Atlantic hurricane season will be very active. This is the highest prediction for hurricanes that CSU has ever issued with their April outlook. The prior highest April forecast was for nine hurricanes, which has been called for several times since the university began issuing April forecasts in 1995. However, the team stresses that the April outlook historically has the lowest level of skill of CSU’s operational seasonal hurricane forecasts, given the considerable changes that can occur in the atmosphere-ocean between April and the peak of the Atlantic hurricane season from August–October.
Overall 23 named storms are predicted during the 2024 Atlantic hurricane season. Of those, researchers forecast eleven to become hurricanes and five to reach major hurricane strength.
So far, the 2024 hurricane season is exhibiting characteristics similar to 1878, 1926, 1998, 2010 and 2020.
Our analog seasons were all very active Atlantic hurricane seasons. This highlights the somewhat lower levels of uncertainty that exist with this outlook relative to our typical early April outlook.
Phil Klotzbach, senior research scientist, Department of Atmospheric Science, CSU
The Colorado State University team predicts that 2024 hurricane activity will be about 170% of the average season from 1991–2020. By comparison, 2023’s hurricane activity was about 120% of the average season.
