We are grateful for the encouragement and grant support of Dr. Stephen Nelson of the National Science Foundation. Partial support for this research was provided by the National Science Foundation through Grants EAR95-12541, ATM-9120009, and ATM-9617318. Additional support was provided by NOAA through a Presidential Early Career Award for Scientists and Engineers. We wish to acknowledge the contribution of Dr. Charles Doswell III through several helpful conversations and a review of this manuscript. We also acknowledge Dr. Robert Maddox for his patience in reviewing two early versions of this paper. Ms. Janelle Janish processed WSR-88D data for its inclusion herein. VORTEX data were collected through the untiring efforts of over 100 participants, many of them volunteers, without which the project could not have succeeded. Mike Smith is acknowledged for several stimulating discussions regarding the potential importance of boundaries to tornadic supercells. Jim Purdom and John Weaver are acknowledged for useful discussions regarding the role and nature of boundaries in general, as well as the behavior of the 2 June 1995 boundary.
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