Date of Award
Summer 2026
Language
English
Embargo Period
7-30-2026
Document Type
Master's Thesis
Degree Name
Master of Science (MS)
College/School/Department
Department of Atmospheric and Environmental Sciences
Program
Atmospheric Science
First Advisor
Kristen Corbosiero
Second Advisor
Brian Tang
Committee Members
Kristen Corbosiero, Brian Tang
Keywords
hurricane, vortex, vortex alignment, TC, tropical cyclone, vorticity
Subject Categories
Atmospheric Sciences | Meteorology
Abstract
Tropical cyclones (TCs) are challenging to forecast when under vertical wind shear (VWS). VWS tilts a TC’s vortex, creating asymmetries in its structure that impedes intensification. Although work has been done to conceptualize and understand how TCs evolve under shear and how they axisymmetrize and intensify, vortex alignment remains a complex and unresolved topic. The goal of this study is to assess what physical processes are important to tilt reduction and how these processes evolve in weak TCs. Using the Hurricane Analysis Forecast System Model-B (HAFS-B) 2.1, a case study on two storms, Hurricane Earl (2022) and Hurricane Lee (2023) were used to investigate how the TC undergoes vortex alignment in moderate wind shear.
Several processes were key in aiding vertical alignment of Lee’s vortex, in which Earl did not have. Deep and persistent convection surrounded Lee’s upper-level vortex, which promoted the concentration of vertical vorticity to organize Lee’s vortex, whereas Earl contained weaker convection that failed to enable vortex alignment. The differences in convective activity were attributed to strong surface fluxes wrapping around the upshear quadrants of Lee, while ample humidification, aloft, propagated upshear to sustain buoyancy and drive deep convection in close proximity to Lee’s upper-level vortex. The surface fluxes in Earl were much weaker, which generated less buoyancy to promote deep convection, despite high moisture aloft. The nuance of Lee’s alignment involved the role of downdrafts providing convergence aloft to organize the vortex structure while inhibiting convection as subsidence intrudes into the inner core. While counterintuitive, this works in unison to align Lee’s vortex as it evolves over a 12-h period.
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Hernandez, Luis O., "KEY PROCESSES INVOLVED IN THE VORTEX ALIGNMENT OF SHEARED TROPICAL CYCLONES" (2026). Electronic Theses & Dissertations (2024 - present). 521.
https://scholarsarchive.library.albany.edu/etd/521