The impact of eastern Pacific tropical cyclones on the climatology of the North American Southwest region

During the North American monsoon season, an additional source of tropical moisture is occasionally advected into the U.S. southwest from the eastern North Pacific in the form of tropical cyclone remnants. Although the tropical cyclone-strength winds rapidly diminish upon making landfall, these systems still carry a large quantity of tropical moisture and, upon interaction with mountainous topography, have the potential to drop copious amounts of precipitation. However, these systems are traditionally difficult to forecast accurately due to the nature of their interaction with the mid-latitude flow.

In this presentation, we will investigate the impact that these tropical cyclone remnants have on the arid North American southwest region. We will study their climatological impact, the preferred rainfall patterns, and the nature of the large-scale circulations that advect their moisture into the southwest U.S. using both observational and model data.