The 1999 Winter Storm Reconnaissance Program, and hence this study, would not have been possible without the work of a large number of participants and collaborators. First, we would like to acknowledge the dedicated work of the NOAA G-IV (led by Sean White) and the USAF Reserve C-130 flight crews (coordinated by Jon Talbot). Coordination with the flight facilities was provided by CARCAH, led by John Pavone. The WSR program benefited from a collaboration with the concurrently run Severe Clear-Air Turbulence Colliding with Air Traffic research program under the leadership of Cecile Girz (NOAA/ERL/FSL) and Mel Shapiro (NCAR). The European Centre for Medium-Range Weather Forecasts is credited for providing their ensemble forecast data to be used in the sensitivity calculations in real time. The forecast cases were selected in real time by NWS field office and NCEP/HPC forecasters coordinated by David Reynolds. Mark Iredell, Jack Woollen, and Timothy Marchok provided valuable help with setting up the parallel analysis–forecast cycle, manipulating data, and creating graphics. The support and advice of Stephen Lord of EMC in organizing and running the field program was invaluable. Glen White, Milija Zupanski, Ralph Petersen, and one of the anonymous reviewers provided helpful comments on an earlier version of this manuscript. We are especially grateful to Anders Persson of ECMWF for his advice in the preparation of Fig. 4 and for sharing with us his thought-provoking notes on downstream development and potential vorticity thinking. The work of S. J. Majumdar and C. H. Bishop (B. J. Etherton and C. H. Bishop) was partly supported by the Grant NSF ATM-96-12502 (NSF ATM-98-14376).
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