Climate model predictions based on greenhouse forcing are often summarized by claiming that future years will be drier. The situation for Nevada, which includes most of the hydrographic Great Basin, may diverge from this general statement. Based on publicly available data (from website ftp://ftp.ncdc.noaa.gov/pub/data/cirs/), the average annual PDSI for the State of Nevada between January 1931 and December 1980 was equal to 0. The prediction will not be true if the average annual PDSI for Nevada between January 1981 and December 2030 will be less than 0. No statistical tests will be used, and the average will be rounded to the nearest integer. Therefore, "less than 0" truly means less than -0.500, and the prediction will still be true if the average annual PDSI for Nevada between January 1981 and December 2030 will be equal or more than -0.499.
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