A climatology of northwest Missouri snowfall events: Long-term trends and interannual variability

The goal of this study was to develop a 50-yr. statistical climatology of snowfall occurrences using data from a dense network of cooperative station observations covering northwest and central Missouri, and these records were provided by the Missouri Climate Center. This included a study of the long-term trends and interannual variability in snowfall occurrence as related to sea surface temperature variations in the Pacific Ocean basin associated with the El Ni (n) over tildeo and Southern Oscillation (ENSO) and the North Pacific Oscillation (NPO). These trends and variations were then related to four synoptic-scale flow regimes that produce these snowfalls in the Midwest. The results demonstrate that during the snowfall season (Oct-April) the northwest Missouri region can expect about eight snowfall events which produce greater than or equal to3 in. (>7.5 cm) of accumulation. While no significant long-term trend in overall snowfall occurrence was found, a decrease in the number of extreme events (greater than or equal to10 in., >25 cm) was noted. Also, fewer snowfall events were found during El Ni (n) over tildeo years, while more heavy snowfall events occurred during "neutral" years, and these results could be related to synoptic-scale variability. A closer examination of the results demonstrated that El Ni (n) over tildeo/La Ni (n) over tildea related variability in snowfall occurrence was superimposed on longer-term NPO-related variability. Interannual variability.