The Evolution Of Atlantic Hurricanes That Undergo Extreme Rapid Intensification
Presenter: Lauren Porter1
Co-Author(s): Dr. David Ryglicki
Advisor(s): Dr. Kim Wood
1Department of Hydrology and Atmospheric Sciences, University of Arizona
Tropical cyclones (TCs), known as tropical storms or hurricanes in the North Atlantic basin, can produce significant hazards such as heavy rainfall, strong winds, and storm surge, with the magnitude of such hazards affected by their size, intensity, and forward speed. Warming ocean waters are known to affect the likelihood of intensification for a given TC, and recent Atlantic hurricane seasons have produced numerous storms that intensified on approach to land, exacerbating their impacts on coastal populations. The canonical definition of rapid intensification (RI) is an increase of 30 kt in 24 hours, but TCs can and do exceed this threshold. This study investigates recent Atlantic hurricanes that intensified at least 35 kt in 24 hours to assess their structural evolution and the environmental factors that may have supported rapid intensity change. Selected cases are limited to the open tropical Atlantic to reduce influences from land and mid-latitude flow, and a 96-hour period that encompasses RI is evaluated for each case. Observations from the Advanced Baseline Imager, operational on GOES-16 since 2018, are used to evaluate convective evolution and the tropical cyclone diurnal cycle. Passive microwave observations, which reveal TC structure below cloud tops, highlight how the TC eyewall contracts as it rapidly intensifies. This presentation will discuss how each storm's environment supported its extreme RI and outcomes of the subsequent eyewall replacement cycle, a process that tends to lower maximum wind speed but result in a larger hurricane.