Trends and ENSO-Related Variability in Atlantic Tropical Cyclone Intensity and Intensification

Abstract This study examined trends and ENSO-related variability in Atlantic tropical cyclone intensity, focusing on 24-h intensification, lifetime maximum intensity (LMI), and rapid intensification (RI) in best-track data during the period 1982–2024. Previous studies considered trends and ENSO influences separately, reporting upward trends in intensity and more cases of RI during La Niña conditions. Here, we extended and built upon prior work by including data through 2024, assessing the impact of ENSO on LMI and 24-h intensification, and analyzing a new storm metric called lifetime maximum 24-h intensification (LM24I). The statistical methods employed here improve upon previous ones by better assessing uncertainty and statistical significance, simultaneously estimating trends and ENSO-related variability, and addressing problems arising from the 5-kt (1 kt ≈ 0.51 m s −1 ) discretization of best-track intensity data. Quantile and logistic regression were employed extensively. The main findings include the following: Prior estimates of intensification trends were overconfident, and including recent data reduces prior estimates of trends in intensification, RI frequency, and LMI. The distribution of LM24I shows significant upward trends of 3–5 kt decade −1 in its top quantiles and broad increases of 2–5 kt per degree of Niño-3.4 cooling. During La Niña conditions, the frequencies of RI events and RI storms increase, and the distributions of 24-h intensification and LMI show previously unreported broad and significant increases. Directions for future research include applying the same approaches to other intensity metrics, basins, and model output, and leveraging ENSO predictability for seasonal intensity prediction. Significance Statement This study examined how the intensity (wind speed) of tropical cyclones in the Atlantic has changed over time and how it varies with El Niño and La Niña. In terms of trends, the most intense storms are becoming stronger, and the most extreme rapid intensification is becoming more frequent. During La Niña conditions, intensification rates are higher, and hurricanes are stronger. The use of better statistical techniques and additional data resulted in reduced upward trends compared to prior estimates and a more comprehensive picture of the impacts of El Niño and La Niña on Atlantic tropical cyclone intensity.