Sharanya Majumdar and Sim Aberson acknowledge financial support from the NOAA Joint Hurricane Testbed, and Zoltan Toth and the Environmental Modeling Center at NCEP for making the paper possible via the provision of an account on the IBM SP supercomputer. Craig Bishop, Melinda Peng, and Carolyn Reynolds acknowledge the support of the Naval Research Laboratory and the Office of Naval Research under Program Element 0601153N, Project Number BE-033-03-4M. The extension to the ETKF formulation described in section 2b was performed by Jonathan Moskaitis under funding from UCAR COMET Award S00-24230. The authors are grateful to James Franklin, Brian Etherton, Chun-Chieh Wu, and David Kofron for valuable discussions. Comments by Istvan Szunyogh and two anonymous reviewers improved the manuscript.
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