Climate change and heavy precipitation in the western US from regional climate models

The basic thermodynamics of the atmosphere suggest that a warmer climate would lead to an enhanced water cycle, amplifying moisture flux and convergence. In general, global climate model projections of climate change scenarios yield this result, with dry seasons and locations becoming dryer and wet seasons and locations becoming wetter. The implications of climate change for local heavy precipitation, however, is not as straightforward. The frequency of extreme precipitation can not be expected to match changes in total precipitation. While many areas have experienced record heavy precipitation in recent years, historic observations over the western United States do not reveal a consistent pattern of increased extreme precipitation.

This talk will use observations and regional climate simulations using the WRF and HadRM models to explore how climate change and variability affect extreme precipitation over the region and how extreme precipitation may change under climate change projections. The talk will discuss the skill of regional models in simulating observed precipitation extremes, simulated and observed 20th century variability, and future projections of heavy precipitation.