Variations in the Spatial Distribution, Persistence Characteristics and Dynamics of U.S. Summer Heat Waves

US summer heat waves display considerable spatial variations regarding their frequency of occurrence, geographic distribution and persistence characteristics, all of which are sensitive to their definition.  There are also substantial diferences in the character and dynamical evolution of heat waves when (and how) atmospheric water vapor is included in defining heat waves.  This paper first shows how the geographical distribution, spatial structure and persistence characteristics of heat waves varies with defintion.  Examples for daily maximim and minimum temperature, apparent tempersture and equivalent temperature will be given along with a summary of the covariability of temperature and specific humidity across the US.  The evolution of specific heat wave events of different types will be presented to highlight differences in their dynamics.  Finally, how well these varying characteristics of heat waves are captured in CMIP5 coupled model simulation for the US will be briefly summarized.