On June 5th, 2009, a tornado was observed in Goshen County, Wyoming by the VORTEX (Verification of the Origins of Rotation in Tornadoes Experiment) 2 Armada. Dual-Doppler radar data of the tornado was collected at close range by the Doppler on Wheels (DOW) 6 and 7 mobile Doppler radars. In addition, a series of photographs of the tornado were taken by two photo teams and were integrated with the dual-Doppler radar data using photogrammetric techniques. This analysis resulted in questioning the validity of the dual-Doppler derived low-level winds in and around the tornado due to the centrifuging of hydrometeors and the relatively coarse data resolution as the DOW 6 radar was no closer than about 14 km from the tornado.

In an attempt to verify the low-level wind structure surrounding the tornado, the Ground-Based Velocity Track Display (GBVTD) technique was used to retrieve the azimuthally-averaged radial and tangential flows surrounding the tornado. DOW 7 data was used in the GBVTD analysis for times when the tornado was within 10 km of the radar. This poster will show results that compare the GBVTD flow field with the dual-Doppler winds and visual features of the tornado funnel.