Recent Increasing Trend in October–November Caribbean Tropical Cyclone Activity

Journal Article · Thu Jan 01 00:00:00 EST 2026 · Geophysical Research Letters

DOI:https://doi.org/10.1029/2025gl120183· OSTI ID:3029009

Klotzbach, P J; Silvers, L G; Bercos‐Hickey, E; Allen, C J T; Bell, M M; Blake, E S; Bloemendaal, N; Bowen, S G; Chand, S S; Chavas, D R; Ekström, M; Hemmati, M; Jones, J J; Lowry, M R; Patricola‐DiRosario, C M; Schreck, C J; Truchelut, R E; Wood, K M

October–November Caribbean tropical cyclone (TC) activity has significant impacts for both the Caribbean islands and Central America (e.g., Hurricanes Eta and Iota in 2020). October–November Caribbean TCs can also track northward and make continental United States landfall, resulting in substantial damage and fatalities (e.g., Hurricane Michael in 2018 and Delta and Zeta in 2020). We find significant increasing trends in October–November Caribbean hurricanes, rapidly intensifying hurricanes (winds increasing by ≥15 m s−1 within 24 hr), and landfalling hurricanes during the global satellite era (1979–present). Since 1979, we also observe significant warming trends in the western Atlantic Warm Pool and anomalous relative cooling in the eastern Pacific during October–November. These trends yield a more conducive dynamic and thermodynamic environment for Caribbean TCs, including reductions in Caribbean vertical wind shear, increases in Caribbean potential intensity, and a more TC‐conducive African easterly jet. October–November hurricane activity can significantly impact the Caribbean islands and Central America. For example, Hurricanes Eta and Iota in 2020 made landfall in Nicaragua at major hurricane strength less than 2 weeks apart, resulting in over 200 direct fatalities. Caribbean hurricanes can also turn northward and hit the continental United States. Three hurricanes (Michael in 2018, Delta and Zeta in 2020) together caused 23 direct fatalities and at least $32 billion USD in damage. In this study, we examine trends in October–November Caribbean hurricane activity since 1979, when global satellite coverage improved. We find that Caribbean hurricanes are happening more often, hitting land more often, and strengthening more quickly. Also, the portion of the North Atlantic Ocean known as the Atlantic Warm Pool (the western tropical Atlantic and the Caribbean Sea) is getting warmer at the same time as the eastern and central tropical Pacific Ocean are becoming more like La Niña (the tropical eastern and central Pacific Ocean are cooler than normal). This combination results in conditions that tend to support tropical cyclones in the Caribbean, such as less vertical wind shear and more mid‐level moisture. October–November Caribbean tropical cyclone (TC) activity has increased since 1979, most notably for hurricane‐strength TCs The western Atlantic has trended warmer while the equatorial Pacific has trended toward La Niña, favoring late‐season Caribbean TCs Environmental conditions have trended more favorable for Caribbean TCs, including lower vertical wind shear and higher ocean temperatures October–November Caribbean tropical cyclone (TC) activity has increased since 1979, most notably for hurricane‐strength TCs The western Atlantic has trended warmer while the equatorial Pacific has trended toward La Niña, favoring late‐season Caribbean TCs Environmental conditions have trended more favorable for Caribbean TCs, including lower vertical wind shear and higher ocean temperatures

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Department of Energy; USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23), Climate and Environmental Sciences Division (SC-23.1 )
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 3029009
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 4 Vol. 53
• Country of Publication: United States
• Language: English