A Climatology of Northwest Missouri Snowfall Events: Long Term Trends and Interannual Variability.

Abstract

The goal of this study was to develop a 50-year 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 Nino 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 three or more inches of accumulation. While no significant long-term trend in overall snowfall occurrence was found, a decrease in the number of extreme events (10 or more inches) was noted. Also, fewer snowfall events were found during El Nino 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 Nino/La Nina related variability in snowfall occurrence was superimposed on longer-term NPO-related variability.