Cloud photogrammetry and single-Doppler radar analysis of the 5 June 2009 La Grange, WY tornado during VORTEX 2

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Sunday, 17 January 2010
Exhibit Hall B2 (GWCC)
Rachel Ducharme, Lyndon State College, Lyndonville, VT; and A. McGee and N. Atkins

On 5 June, 2009, a supercell over Goshen CO, Wyoming spawned an EF 2 tornado with a path length of approximately 15 km. This tornado was well-sampled by the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX) 2 armada. In particular, high resolution digital imagery and HD video were collected well before tornado genesis through the dissipation stage. Concurrent high-resolution mobile Doppler radar data was collected by a number of platforms. Relevant to this study, the Doppler on Wheels (DOW) 6 and 7 radars collected dual-Doppler radar observations within 15 km of the tornado well before tornado genesis until a few minutes before tornado dissipation.

Many digital images of the wall cloud and tornado have been photogrammetrically analyzed. This poster will present results where, for the first time, photogrammetrically analyzed photos of the tornado are combined with single-Doppler DOW data. An important result of this analysis is the source of high-reflectivity rings that often surrounds the tornado. While previous research has speculated that debris is responsible for the high-reflectivity rings, it will be shown that a high-reflectivity ring surrounding the La Grange tornado is due primarily to precipitation wrapping around the circulation. Results showing the concurrent evolution of the tornado funnel and parent mesocyclone observed in the radar data will also be presented.