The Development of Persistent Atmospheric Rivers

Landfalling atmospheric rivers (ARs) are linked to heavy precipitation and extreme flooding, most notably along the western coast of North America. The duration and magnitude of landfalling ARs are correlated to their hydrological impacts on land. Previous work comparing a subset of persistent wintertime (October - March) landfalling ARs to all other landfalling events shows they have distinct moisture and circulation features. Here, we use the Weather Research and Forecasting (WRF) model to simulate the development of three, well observed, persistent landfalling events at high resolution (4 km) in order to investigate the role of moisture in AR persistence along the coastline. Our model configuration is validated against dropesonde observations from the CALJET and PACJET campaigns. We present a comparison of the control simulation to a series of sensitivity experiments in which the timing and amount of latent heat release is modified.