Increasing Hurricane Intensification Rate Near the US Atlantic Coast

Abstract

Hurricanes often cause severe damage and loss of life, and storms that intensify close to the coast pose a particularly serious threat. While changes in hurricane intensification and environment have been examined at basin scales previously, near‐coastal changes have not been adequately explored. In this study, we address this using a suite of observations and climate model simulations. Over the 40‐year period of 1979–2018, the mean 24‐hr hurricane intensification rate increased by ∼1.2 kt 6‐hr−1 near the US Atlantic coast. However, a significant increase in intensification did not occur near the Gulf coast over the same period. The enhanced hurricane intensification along the Atlantic coast is consistent with an increasingly favorable dynamic and thermodynamic environment there, which is well simulated by climate models over the historical period. Further, multi‐model projections suggest a continued enhancement of the storm environment and hurricane intensification near the Atlantic coast in the future.

Increased U.S. coastal hurricane risk under climate change

“…The CMIP6 multimodel ensemble suggests that wind shear will likely reduce near the East Coast of the United States and the northern Gulf of Mexico (Fig. 5A), in line with several previous studies ( 24 , 25 , 28 , 29 ). When the SWM is forced by simultaneous changes in basic states, diabatic heating, and transient eddies, it broadly reproduces the spatial pattern of wind shear responses over the North Atlantic and the eastern Pacific (Fig.…”

“…5D). Thus, in addition to altering the steering flow, future changes in diabatic heating could lead to increases in hurricane intensification (24,25) and tropical cyclogenesis (34) near the U.S. coast through the influence on wind shear, highlighting the broad implication of the mechanism identified in this study. Nevertheless, the projected decrease in translation speeds over the subtropical North Atlantic (Fig.…”

“…Therefore, besides exploring changes in various aspects of hurricanes on the global scale, a better understanding of how hurricane characteristics will evolve on regional scales is particularly important for assessing future losses resulting from landfalling storms. As indicated by a number of studies, anticipated stalling of storms (16)(17)(18)23), increasing hurricane intensification rates (24,25), and slower dissipation after landfall (26) could pose greater hazards to coastal communities in future (27). In addition, future growth in population and wealth along the U.S. Gulf and East coasts combined with rising sea levels (6,15) could further exacerbate the risk associated with landfalling hurricanes (2).…”

“…Despite this, the physical mechanisms responsible for how anthropogenic climate change will influence certain aspects of hurricanes in the nearshore region are not well understood. For instance, climate models project a robust decrease in vertical wind shear near the U.S. coast (24,25,28,29), but the underlying physical rationales have not been firmly established. Similarly, the relative importance of various processes leading to the slowdown of storms (16)(17)(18)23) and changes in hurricane landfall (30)(31)(32)(33)(34) remains unclear.…”

North Atlantic Tropical Cyclone Intensification: Regional Drivers and Trends

“…Given that atmospheric and oceanic features vary across the Atlantic basin, TC intensification rates and their relationships with environmental variables may also vary by region. Their trends may vary by region too, and there is scope to build on Balaguru et al (2018Balaguru et al ( , 2022 and Bhatia et al (2022) to reveal new regional relationships. To date, no studies have investigated observed regional trends using probability density functions (PDFs) of TC-relative environmental variables, for RI versus slower intensification.…”