Publication Date

Summer 2020

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Meteorology and Climate Science

Advisor

Sen Chiao

Keywords

HWRF, Large Scale, Rapid Intensity, Tangential Wind Budget, Tropical Cyclones

Subject Areas

Meteorology

Abstract

Rapid Intensification (RI) in TCs still remains one of the most challenging tasks for forecasters. The lack of understanding of the physical mechanisms and complexities in charge of these events, limits our understanding and makes it more difficult for weather models to resolves and forecast RI events. The Hurricane Weather Research and Forecasting (HWRF) model was used to examine the connection between rapid intensification and environmental forcing for Hurricane Irma (2017) and Hurricane Michael (2018). The tangential wind momentum budget was used for a comparative analysis for these two cases to identify similarities and differences in the pathways to intensification in varied environments. The eddy radial vorticity flux term is a focal point as previous studies have found it to have a significant role in intensity change and vortex spin up in sheared tropical cyclones. Our findings based on this work shows that eddy vorticity fluxes negatively impacted the vortex spin up and intensification in both cases. Despite the persistent environmental shear associated with Hurricane Michael, the mean transport of horizontal and vertical momentum was the dominating factor in spin up of the vortex from the bottom up.

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