2026-09-21T07:50:33Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/115443 2023-07-11 col_2142_5131 col_2142_14839 com_2142_5130 com_2142_14838 com_2142_13459 com_2142_8903

Frame, Jeffrey Sriver, Ryan Trapp, Robert J. 2022-05 application/pdf en text Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-11 without embargo terms The student, Rylan Housenga, accepted the attached license on 2022-04-22 at 17:03. The student, Rylan Housenga, submitted this Thesis for approval on 2022-04-22 at 17:09. This Thesis was approved for publication on 2022-04-27 at 14:15. DSpace SAF Submission Ingestion Package generated from Vireo submission #17934 on 2022-11-11 at 13:43:13 Investigating the longevity of significant-tornado producing supercells Housenga, Rylan J 2022-04-27 supercell longevity significant tornado All 1,515 significant (EF-2+) tornadoes and their environments between 2008 and 2018 in the United States are examined, with a focus on parent supercell thunderstorm longevity. Almost all significant tornadoes are produced by discrete supercells (66%) or clusters (27%), and they are most common in the Plains or Southeast between March and June, with a small secondary peak in November in the Southeast. Bulk wind shear and storm-relative helicity (SRH) are moderately correlated (r ≈ 0.35) with the total time that a supercell is discrete, the total number of significant tornadoes produced by a storm, and the total tornado path length associated with a storm. There is no correlation between storm longevity and any thermodynamic variable. Long-lived (≥ 4 hours) supercells are most frequent in the Southeast, where shear and SRH are typically greatest. Additionally, SRH is roughly 50-70 m2 s-2 greater for the longer-lived supercells (≥ 75th percentile) than for the shorter-lived ones. Another key finding is that excessive (≥ 90th percentile) backing or veering of the wind shear vector above 1 km above ground level (AGL) is detrimental to supercell longevity. Thesis eng https://hdl.handle.net/2142/115443 Copyright 2022 Rylan Housenga M.S. Thesis Atmospheric Sciences University of Illinois at Urbana-Champaign Atmospheric Sciences