The Occurrence and Persistence of Wet and Dry Periods In Nebraska, Kansas and Oklahoma, 1931-1975

Abstract

The occurrence and persistence of wet and dry periods is examined in Nebraska, Kansas and Oklahoma from January, 1931 to December, 1975. Monthly Palmer Index values are used to measure wet and dry conditions for the twenty-six climatic divisions in this three state region. Spatial patterns of wet and dry period occurrence and persistence are shown through a series of maps. Analysis of major wet and dry periods over the period of record reveals that cyclone frequency, 700-mb ridge-trough position and 700-mb height anomalies were all associated with these events. These variables show distinct patterns during the onset, maintenance and cessation of wet and dry periods.