This paper was funded in part by the Scripps Institution of Oceanography. Initial funding for the research was provided in part by Technology Research and Investigations, a division of the Technology Group of Eskom. Helpful discussions with D. Bradu, I. Abramson, and L. Goldstein are gratefully acknowledged. The comments of two anonymous referees contributed to a notable improvement to this paper. The rainfall data were obtained from the South African Weather Bureau and Lesotho Meteorological Services.
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