Rainfall occurrence for Oklahoma City is modeled using first and second-order Markov chains, which generate long time series of daily rainfall occurrence data. Occurrence frequencies of wet and dry spells are derived from the models. Model confidence is high for extended wet periods and short dry spells, but drops sharply for dry spells exceeding thirty days. This indicates that the processes underlying the persistence of long wet and dry runs may be significantly different, and that a better understanding of regional dry spell-climatology is needed.
Paper available upon request.