<p>The Midwest (MW) United States (US) is a significant agricultural region sensitive to changes in the local precipitation patterns. Using a Bayesian statistical model, daily regional precipitation is categorized into three classes: light, moderate, and heavy. Results indicate that moderate and heavy precipitation events have been increasing since 1970 at a rate of two days per decade while light precipitation events have been decreasing. To determine the moisture sources for MW US precipitation, a moisture backtracking model is employed. Land is the dominant moisture source contributor to MW US precipitation, but oceanic sources become more important with increasing precipitation intensity. Moisture is transported from the southern oceanic regions to the MW US via the Great Plains Low-Level Jet (GPLLJ), which is strengthened by a northwest displacement of the North Atlantic Subtropical High (NASH) Western Ridge (WR). The positioning of the NASH WR is determined by a wave train originating over the Pacific Ocean that creates a dipole over the US with an anomalous low over the Western US and an anomalous high over the Eastern US. These circulations facilitate a stronger GPLLJ and transport excess ocean moisture to the precipitation region. Additionally, warmer sea surface temperatures yield greater evaporation rates twelve days prior to the heavy precipitation events.</p>