We would like to thank George Kiladis for the OLR data. Vernon Kousky and Jerry Bell provided valuable comments that have helped to substantially improve the manuscript. The authors are also indebted to Siegfried Schubert, Chester Ropelewski, Randall Dole, Robert Black, and Richard Rood for insightful discussions. Thanks also go to Wesley Ebisuzaki, Julian Wang, and Muthu Chelliah for help in preparing the NCEP reanalysis data. This work was partially supported by the NOAA Office of Global Programs under the Pan American Climate Studies (PACS) project and the CDAS/Reanalysis project and by Interagency Agreement S-41367-F under the authority of NASA Headquarters.
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