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The Severe Weather Outbreak of 10 November 2002: Lightning and Radar Analysis of Storms in the Deep SouthOn the afternoon and evening of 10 November 2002, the Midwest and Deep South were struck by a major outbreak of severe storms that produced some 80 tornadoes. In terms of number of tornadoes, this was the largest outbreak in the United States since November 1992. Some 32 of the tornadoes occurred in Tennessee, Mississippi, Alabama and Georgia, including several long-track killers. We use the North Alabama Lightning Mapping Array (LMA) and other data sources to perform a comprehensive analysis of the structure and evolution of the outbreak. Most of the Southern tornadoes occurred in isolated, fast-moving supercell storms that formed in warm, moist air ahead of a major cold front. Storms tended to form in lines parallel to storm cell motion, resulting in many communities being hit multiple times by severe storms that evening. Supercells in Tennessee produced numerous strong tornadoes with short to medium-length track paths, while the supercells further south produced several very long-track tornadoes. Radar data indicate that the Tennessee storms tended to split frequently, apparently limiting their ability to sustain long-lived tornadoes, while storms further south split at most one time. The differences between these storms appear to be related to the presence of stronger jetstream winds in Tennessee relative to those present in Mississippi, Alabama and Georgia. LMA-derived flash rates associated with most of the supercell storm cores were about 1-2 flashes per second. Rapid increases in lightning rates (or "jumps") occurred prior to tornado touchdown in many instances. Lightning "holes" (lightning-free regions associated with the echo-free vault) occurred in two of the Tennessee supercells. The complexity of the relationship between lightning and storm severity is revealed by the behavior of one Alabama supercell, which produced a peak flash rate of nearly 14 flashes per second, well after the end of its long-track tornado, while interacting and ultimately merging with a daughter supercell on its southwest flank. Close examination of this powerful storm indicates that its prodigious flash rate was the result of strong flash activity over an unusually large area, rather than a concentrated core of extremely high flash rate activity.
Document ID
20040170476
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Buechler, D. E.
(Alabama Univ. Huntsville, AL, United States)
McCaul, E. W., Jr.
(Universities Space Research Association United States)
Goodman, S. J.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Blakeslee, R. J.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Bailey, J. C.
(Raytheon Information Technology and Scientific Services United States)
Gatlin, P.
(Alabama Univ. Huntsville, AL, United States)
Date Acquired
August 22, 2013
Publication Date
January 1, 2004
Subject Category
Meteorology And Climatology
Meeting Information
Meeting: American Meteorological Society 22nd Conference on Severe Local Storms
Location: Hyannis, MA
Country: United States
Start Date: October 5, 2004
End Date: October 8, 2004
Distribution Limits
Public
Copyright
Other

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