151 Characteristics of QLCS Downdrafts and Environments Observed during the VORTEX-Southeast Project

Thursday, 25 October 2018
Stowe & Atrium rooms (Stoweflake Mountain Resort )
James Marquis, Univ. of Colorado Boulder, Boulder, CO; and K. Kosiba, J. Wurman, and P. Robinson

Storm-generated downdrafts play a significant role in storm evolution, intensity, and duration. Importantly, the properties of forward-flank and rear-flank downdrafts in supercell storms, and descending rear inflow jets in quasi-linear convective systems (QLCS), have been linked to the occurrence of tornadoes. The VORTEX-Southeast project aimed to observe severe convection in northern Alabama to determine the topographic and environmental influences on tornadoes in the southeastern U.S. Because QLCSs are associated with tornado production in this region of the country, a better understanding of how downdraft and outflow properties of these storms, including radar and environmental pre-cursors, can be used to predict tornadogenesis and other severe weather is needed.

This work utilizes dual-pol and multiple-Doppler radar data collected by several mobile and fixed radars, frequent proximity radiosonde and profiler observations, and surface in situ observations collected in two QLCSs targeted during the VORTEX-Southeast project to characterize storm-scale downdraft processes. This presentation will discuss preliminary synthesized multi-Doppler wind retrievals and dual-pol radar observations of the observed convective downdrafts to relate their four-dimensional kinematic and hydrometeor properties to observations of the surface outflow and free troposphere, including local variations of shear and instability. Comparisons of interacting environmental and storm-scale processes occurring in the southeast U.S. with those observed in the central plains will offer improved understanding of regional severe weather and tornado risks.

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