EAPS

Title: Predictability and dynamics of tropical cyclone intensity changes with highlights from Hurricane Joaquin (2015) and Superstotm Sandy (2012)

Abstract: This study examines the predictability of tropical cyclone formation and intensity under different environmental conditions through a series of cloud-resolving ensemble simulations of both idealized and real-world storms. Special attention will be given to the impacts of vertical wind shear on the hurricane dynamics and intensity changes including rapid intensification (RI) and eyewall replacement cycles (ERCs). It is found even under the same environmental conditions, the tropical cyclone formation and intensity changes can be extremely sensitive to small, unobservable, random initial condition errors, especially during the formation, RI and ERC stages. The upscale error growth from small initial perturbations through random and chaotic moist convection may lead to considerable difference in the intensity variations, which is more so for environmental conditions that are only marginally favorable. A conceptual model will be presented that will elucidate the practical versus intrinsic limits of hurricane intensity predictability.