We thank Eugene Rasmusson for helpful discussions and Harry Lins for providing us the Hydro–Climatic Data Network datasets and for a careful review of the manuscript. Comments by three anonymous reviewers considerably improved the original manuscript. This research was supported by the National Oceanic and Atmospheric Administration’s Pan American Climate Dynamics program (Grant NA76GP0479) and by the National Science Foundation’s Climate Dynamics program (Grant ATM-9422507). Mathew Barlow is a UCAR postdoctoral fellow at IRI.
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