Date of Award
2026
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Atmospheric and Earth Science
Committee Chair
Xiaomin Chen
Committee Member
John Mecikalski
Committee Member
Patrick Duran
Research Advisor
Xiaomin Chen
Subject(s)
Vertical wind shear, Cyclones--Tropics, Atmospheric circulation, Hurricane Nicholas (2021)
Abstract
Predicting tropical cyclone (TC) rapid intensification (RI) under moderate-to-strong vertical wind shear (VWS) remains challenging, particularly when cyclogenesis and RI occur within 48 hours of landfall, as with Hurricane Nicholas (2021). This study analyzes Nicholas’ RI using NOAA’s Hurricane Analysis and Forecast System. Results reveal a two-stage vortex alignment before the early RI stage: diabatic heating first draws the mid-level center toward the low-level center, followed by cyclonic precession. A nearly-saturated core below 500 mb develops before RI onset as column-integrated moist static energy (MSE) increases, and the moistening process continues during the early RI stage as surface heat and shortwave radiative fluxes effectively offset VWS-induced ventilation. Nicholas’s RI persists until shortly before landfall, despite enhanced ventilation associated with strong VWS overwhelming surface heat fluxes, reducing column-integrated MSE and increasing vortex tilt. Interestingly, land-friction-induced boundary layer spinup of the primary circulation is identified as a key contributor.
Recommended Citation
Prunty, Ethan O., "Impacts of vertical wind shear and coastal friction on the pre-landfall rapid intensification of Hurricane Nicholas (2021)" (2026). Theses. 850.
https://louis.uah.edu/uah-theses/850