Winter Extreme Precipitation Regimes (EPRs) in Eastern North America: Teleconnections, Rossby Wave Characteristics, and Case Study

Long-lived and widespread extreme precipitation periods often lead to flooding, causing loss of life and property. Forecasting such periods is still a significant challenge, and a better understanding of them would help improve their prediction at longer lead times. However, extreme precipitation studies have generally focused on one storm or shorter-duration events. I aim to study these events in more detail during the eastern North American winter, defining them as extreme precipitation regimes (EPRs).

I assess correlations between EPRs and large-scale atmospheric indices, such as the El Niño-Southern, Madden-Julian, North Atlantic, and Pacific North-American oscillations. I also assess atmospheric blocking and Rossby wave characteristics during EPRs and their implications for EPR evolution and properties. Finally, I present a case study of a series of three EPRs in February 2019 that contributed to major flooding in the Ohio and Mississippi Valleys, a record wet winter in the contiguous United States, and unusually snowy winter in Ontario and Quebec, especially north of the St. Lawrence River.