Earth and Atmospheric Sciences, Department of
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
First Advisor
Matthew S. Van Den Broeke
Committee Members
Walker Ashley, Adam L. Houston
Date of this Version
8-2025
Document Type
Thesis
Citation
A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science
Major: Earth and Atmospheric Sciences
Under the supervision of Professor Matthew S. Van Den Broeke
Lincoln, Nebraska, August 2025
Abstract
A study of hail occurrence in quasi-linear convective systems (QLCS), as well as severe weather parameters contributing to the likelihood and intensity of hail, is presented. Rapid Refresh (RAP) proximity soundings for 218 QLCS events from 2012 to 2022 are selected to sample QLCS environments near peak intensity. Study objectives are to assess common environmental parameter spaces that favor hail in QLCSs while connecting these findings to results for supercells. Hail occurrence is also examined in terms of synoptic regime.
Six synoptic regimes were identified to support QLCSs with hail, from high shear, low cape (HSLC) to low shear, high CAPE (LSHC), deep trough, closed low, open trough, zonal flow, ring of fire, and weak flow. Hail was favored in cases with a dry boundary layer, steep lapse rate, and weak low-level shear. Hail count was evenly distributed across synoptic regimes, except for ring of fire and weak flow regimes, which had notably lower median hail counts. Cases with a large hail count predominately occurred over the Great Plains. This distribution is hypothesized to be heavily influenced by the geographic variability of mean United States severe weather environments.
Advisor: Matthew S. Van Den Broeke
Comments
Copyright 2025, Cameron A. Barker. Used by permisison