305 Precipitation Properties and Processes Linking Vertical Motion, Lightning, and Severe Weather

Monday, 23 January 2017
4E (Washington State Convention Center )
Sarah M. Stough, Univ. of Alabama, Huntsville, AL; and L. D. Carey, C. J. Schultz, and D. J. Cecil
Manuscript (10.0 MB)

Handout (8.8 MB)

Recent work in the area of lightning meteorology has refined understanding of the microphysical and kinematic catalysts of rapid increases in total lightning flash rate, or lightning jumps, further characterizing the physical origins and significance of lightning jumps. This work has also continued to demonstrate the utility of the lightning jump for nowcasting applications where its occurrence has been shown to often precede observations of severe weather, manifested as large hail, strong straight-line winds, or tornadoes. The updraft generally serves as the common link between lightning and severe weather production with the most direct, updraft-centric relationship between lightning and severe weather belonging to hail formation. Meanwhile, the links between the updraft-driven lightning jump and subsequent observations of downdraft-influenced strong straight-line winds at the surface and tornadogenesis are more complex.

Although it is understood that the processes responsible for flash production and lightning jumps are closely tied to the updraft of a convective storm, the spatial distribution of lightning flashes that occur during a rapid increase in lightning flash rate and the broader microphysical characterization thereof have not been examined as closely in the literature, particularly with respect to how hydrometeor fields evolve following the jump. To better understand the relationship of lightning to the microphysical controls on downdrafts and their byproducts of high-impact weather, the work presented here considers the three-dimensional spatial distribution of lightning that participates in a lightning jump, the precipitation properties and processes in these flash regions, and their evolution following jumps in a selection of case studies. Information afforded by polarimetric Doppler radar, hydrometeor identification algorithms, and multi-Doppler analysis when available are used first to characterize the microphysics of regions where lightning occurs leading up to and during the time of a lightning jump, then to examine the evolution of those regions as they relate to kinematics in convective storms. Implications from results of this work are varied and may be extended to multiple applications. Preliminary results of analysis presented here will focus on further characterizing the spatial relationship of the lightning jump to microphysical structure of the updraft as well as relating lightning to downdrafts through study of the hydrometeors and microphysics that influence, and link, both processes.

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