Observations from VORTEX2: The genesis and intensification of the Goshen County, Wyoming tornado (05 June 2009)

A dual-Doppler and thermodynamic analysis of the genesis and the intensification of an EF-2 tornado observed on 5 June 2009 in Goshen County, WY during the VORTEX2 field campaign will be presented. Prior to tornadogenesis dual-Doppler analyses revealed the beginning of a wind surge in the rear-flank downdraft. This surge was followed by the development of a secondary gust front located behind the primary rear-flank gust front and adjacent to the developing tornadic circulation. Through trajectory analysis and the integration of mobile mesonet data, the importance of this change in rear-flank downdraft structure and its link to tornadogenesis and tornado intensification will be discussed in the context of vorticity generation and/or transport. Changes in reflectivity structure, including the development of a low reflectivity ribbon, during this time interval also will be examined.