Examining the role of deep convective updrafts in QLCS tornadogenesis using observations and real-world modeling

Wolff, Edward Clarence

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https://hdl.handle.net/2142/121529 Copy

Description

Title

Examining the role of deep convective updrafts in QLCS tornadogenesis using observations and real-world modeling

Author(s)

Wolff, Edward Clarence

Issue Date

2023-07-17

Director of Research (if dissertation) or Advisor (if thesis)

• Trapp, Robert J
• Nesbitt, Stephen W

Committee Member(s)

Kosiba, Karen

Department of Study

Atmospheric Sciences

Discipline

Atmospheric Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• tornado
• severe weather
• updraft
• vortex
• mesovortex
• QLCS
• PERiLS
• thunderstorm
• overshooting top
• WRF
• weather research and forecasting model
• MRMS
• multi-radar multi-sensor
• reflectivity
• radar
• GOES
• satellite
• southeast

Abstract

Tornadoes that form from quasi-linear convective systems (QLCSs) are especially difficult to predict and identify, leading to lower situational awareness and shorter warning lead times. QLCS tornadoes are especially prevalent in the Southeast United States and societal factors within this region make these tornadic QLCSs especially devastating to the communities they impact. It is hypothesized that stronger, severe circulations tend to be associated with deep updrafts and overshooting convection, whereas weaker, non-severe circulations are not. To address this hypothesis, local storm reports and storm surveys during the second Intensive Observing Period of the 2022 Propagation, Evolution, and Rotation in Linear Storms (PERiLS) field campaign are used to identify low-level tornadic circulations within the QLCS. These circulations are then compared to upper-tropospheric features, such as overshooting tops (OTs), which are calculated with an OT identification algorithm using 1-minute resolution mesoscale sector data from the GOES-16 satellite, as well as strong updrafts, identified with multi-radar multi-sensor (MRMS) 3D mosaic reflectivity products. Only a fraction of tornadoes within the QLCS exhibit overshooting convection, though all tornadoes are co-located with upper- tropospheric reflectivity cores. To augment the observational analysis, a numerical simulation of the event is also conducted using the Weather Research and Forecasting model (WRF). Feedbacks between updrafts and circulations in QLCSs are also explored. The identification of updraft and tornadogenesis signatures within high-resolution geostationary satellite and MRMS data may ultimately help improve the identification of regions within QLCSs most likely to result in damaging circulations.

Graduation Semester

2023-08

Type of Resource

Thesis

Copyright and License Information

Copyright 2023 Edward C. Wolff

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