Hurricane researchers at Colorado State University (CSU) have predicted an especially active hurricane season in their initial 2024 forecast. CSU researchers state, in a recent report, “The team cites record warm tropical and eastern subtropical Atlantic sea surface temperatures as a primary factor for their prediction of 11 hurricanes this year.” A prediction of an extreme, record-breaking hurricane season was also recently reported by AccuWeather.
The Conditions for a Perfect Storm
The report, describing the conditions that create an environment conducive to hurricanes, states, “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…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 to October.”
2024 Named Storms
The CSU team predicts 23 named storms during the Atlantic hurricane season, which runs from June 1 to Nov. 30, with 11 forecast to become hurricanes and five reaching major hurricane strength (Category 3 and higher). The CSU team based its forecasts on a statistical model and “four models that use a combination of statistical information and model predictions of large-scale conditions from the European Centre for Medium-Range Weather Forecasts, the UK Met Office, the Japan Meteorological Agency, and the Centro Euro-Mediterraneo sui Cambiamenti Climatici. These models use 25-40 years of historical hurricane seasons and evaluate conditions including: Atlantic sea surface temperatures sea level pressures, vertical wind shear levels (the change in wind direction and speed with height in the atmosphere), El Niño (warming of waters in the central and eastern tropical Pacific), and other factors.” So far, according to the report, the 2024 hurricane season is exhibiting characteristics similar to 1878, 1926, 1998, 2010, and 2020.
The 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. The most significant hurricane of the 2023 Atlantic hurricane season was Hurricane Idalia. Idalia made landfall at Category 3 intensity in the Big Bend region of Florida, causing $3.6 billion dollars in damage and resulting in eight direct fatalities.”
Hurricane Landfall Probability
The report predicts that there is a 62% probability of major hurricanes making landfall “for the entire U.S. coastline (average from 1880-2020 is 43%); 34% for the U.S. East Coast, including the Florida peninsula (average from 1880-2020 is 21%); 42% for the Gulf Coast from the Florida panhandle westward to Brownsville (average from 1880-2020 is 27%); and 66% for the Caribbean (average from 1880-2020 is 47%).”