Past and Future Rainfall from Dissipating Tropical Cyclones in Southwestern California

While California is not normally thought of as a region affected by tropical cyclones, about one per year sends enough moisture northward to produce rainfall in California, typically during the late summer or early fall. The precipitation from these systems can be significant for a couple of reasons: (1) it can produce thunderstorms that may become severe and produce flash flooding and (2) even when the precipitation is more stratiform and less intense, it can delay the start of the fall fire season. In this investigation we look in detail at the effects of several of these tropical cyclones, including Odile in 2014 and Dolores in 2015. The storms are examined through both observations (gauges and radar) as well as high resolution WRF modeling in order to better understand the dynamics and moisture distribution that leads to the precipitation. This is the beginning of a broader study of the effects of these dissipating cyclones in California and the implications for a future warmer climate.