The 2024 Atlantic Hurricane Season officially ended on November 30, and while it was an above average year, seasonal activity didn’t quite reach the AEM’s forecast predictions anticipating one of the most active seasons on record.

Leading into the hurricane season, AEM forecasters noted warmer than average water temperatures in the Gulf of Mexico and tropical Atlantic Ocean would be one of the top driving forces for above-average hurricane forecasts. Another key contributor was expected to be the El Niño Southern Oscillation (ENSO), which would feature the development of a weak La Niña during the summer into the autumn. Combined, these factors signaled an increased probability of an active Atlantic Hurricane season.

AEM meteorologists, in their annual hurricane season outlook, predicted 20 to 26 named storms to form, with nine to 13 becoming hurricanes and five to seven of those hurricanes becoming major hurricanes with sustained winds of at least 111 mph. This was well above the long-term Atlantic season average of 14 named storms, 7 hurricanes and 3 major hurricanes.

The 2024 Atlantic Hurricane Season featured 18 named storms, 11 hurricanes, and 5 major hurricanes. While the number of named storms was below the seasonal forecast, the number of hurricanes and major hurricanes were accurately predicted.

Total Accumulated Cyclone Energy (ACE) was forecast to reach 180 to 250 units, but 2024 ended with a score of 161.63, which was the 12th highest ACE score since 1951, and the 2nd highest this decade.

Prior to the start of the 2024 Atlantic Hurricane Season on June 1, the AEM meteorology team predicted that La Niña would return after a multi-year period of warmer water in the eastern Pacific Ocean, also known as El Niño. The transition to La Niña was expected by peak hurricane season, historically between mid-August and early October. However, neutral conditions continued, and La Niña did not return by the end of the season.

Several other factors hampered activity during the typical peak of the season, primarily from the middle of July through late September. A northward-shifted monsoon trough resulted in African easterly waves emerging at too far north of a latitude, extremely warm upper-level temperatures led to stabilization of the atmosphere and increased easterly shear limited development in the eastern Atlantic.

Extensive plumes of dust, called the Saharan Air Layer (SAL), also pushed across much of the eastern Atlantic during June, July and August. The air surrounding the SAL has about 50-percent less moisture than the typical atmosphere. This means the presence of the SAL was detrimental to cloud formation and thunderstorm activity.

Tropical activity eventually picked up quickly beginning in late September, with 7 hurricanes forming by early November, propelling the season to be officially classified as “extremely active” or “hyperactive” in mid-November.

AEM’s forecast methodology involves using machine learning techniques to better decipher complex ocean-atmosphere linkages related to the hurricane season. Latest ocean water temperature anomalies, forecast summer ocean water temperature anomalies West African rainfall, and analog years— years with similar predictor patterns to 2024, are analyzed.

Latest ENSO projections indicate a weak La Nina will develop this winter then gradually weaken during the spring of 2025. By the time the next hurricane season rolls around on June 1, 2025, a neutral ENSO state will be possible. AEM will issue its 2025 Atlantic hurricane seasonal outlook in May 2025.

Story Image: 2024 Atlantic AEM Hurricane Outlook Verification

2024 AEM Atlantic Hurricane Outlook Review