AN EXPLORATION OF THE MARSUPIAL PARADIGM IN DEVELOPING AFRICAN EASTERLY WAVES FROM 2020: JOSEPHINE, ISAIAS, AND LAURA

• Main Author: Britton, Scott C.
• Other Authors: Montgomery, Michael T., Meteorology (MR), Powell, Scott
• Format: Thesis
• Language: unknown
• Published: Monterey, CA; Naval Postgraduate School 2021
• Subjects: hurricane; Lagrangian; marsupial paradigm; MP; Okubo-Weiss; OW; pouch; prediction; tropical cyclone; TC; Josephine; North Atlantic
• Online Access: https://hdl.handle.net/10945/67674

This thesis applies the marsupial paradigm (MP) conceptual model of tropical cyclone (TC) formation previously used to describe the transition from a tropical disturbance to a tropical depression. A case study of three storms that formed from African easterly waves in the North Atlantic during the 2020 hurricane season, Isaias, Josephine, and Laura, provides insight into the pre-formation structures called wave-pouches. The analysis evaluates several variables including the Okubo-Weiss (OW) parameter, relative vorticity, relative humidity, and vertical shear in a comoving (quasi-Lagrangian) framework. Additionally, GOES-16 Channel 13 infrared imagery emphasizing cloud presence was coupled in sequence with the analyses to reveal connections between wave-pouch structure and observed developing convection. Furthermore, this work addresses pouch interactions with shear and other pouches or vortices. The study concludes with recommendations to forecasters on how to incorporate the MP into pre-TC analysis alongside the global numerical weather model outputs. Approved for public release. Distribution is unlimited. Lieutenant Commander, United States Navy