Theses and Dissertations

Advisor

Mercer, Andrew E.

Committee Member

Meng, Qingmin

Committee Member

Brown, Michael E.

Committee Member

Marsh, Patrick

Date of Degree

8-13-2024

Original embargo terms

Immediate Worldwide Access

Document Type

Graduate Thesis - Open Access

Major

Geosciences

Degree Name

Master of Science (M.S.)

College

College of Arts and Sciences

Department

Department of Geosciences

Abstract

Past research has primarily focused on tornado outbreak intensity; however, this study presents an updated ranking index scheme that provides intensity ranks for both hail and tornado-dominant outbreaks. All outbreaks spanning 1960 - 2022 were obtained using a 24-hour kernel-density-based approach to map the severe weather report density. Notably, secular trends in the annual means of many of these variables (such as the number of hail and wind reports) showed a significant upward trend until 2010, after which that trend flattened. Thus, these fields were detrended using support vector regression that better fit these parameters' underlying annual time series. The resulting indices delineate between tornado and hail-dominant outbreaks, allowing further investigation into mixed-mode outbreaks and synoptic-scale precursors of these unique outbreak modes. It also provides an objective measure of outbreak intensity which can be useful when assessing potential future impacts from events with similar meteorological characteristics.

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