An Analysis of Atmospheric River Evolution and Moisture Region Source in the Eastern US

Atmospheric Rivers (ARs) are long, narrow, and transient corridors of strong horizontal water vapor transport. They are pathways of intense moisture transport that are connected to extreme weather events around the world. ARs have been identified to contribute to flooding over the central and eastern US, however, questions remain about their development and characteristics. The AR lifecycle and moisture source regions of a small subset of high-impact events were investigated using ERA5 reanalysis and Python. ARs are identified using vertically integrated water vapor transport (IVT). Moisture source regions of the AR case studies were identified using the trajectory model, HYSPLIT from NOAAs Air Resource Laboratory. Our results show that moisture from the Gulf of Mexico is the largest contributor to the ARs studied, with minor moisture sources originating over the western US. Frontal boundaries aid in the propagation of ARs across the region. The AR case studies are strongly correlated with high precipitation events, in agreement with previous studies. Identification of moisture source region and potential influence over precipitation impacts on land can aid in increased resilience to future weather extremes. This study contributes towards an improved understanding of AR characteristics outside of the well-studied western US.