Characteristics of Recent Prolific Daily Rainfall Associated with Tropical Cyclones Impacting the Southern and Eastern United States

Aspects of prolific rainfall associated with tropical cyclones (TC) over the eastern and southern United States will be examined. Many of the cases examined produced devastating flooding. Differences in rainfall patterns and forecaster confidence produced a variety of communication challenges that will be analyzed and discussed. These tropical rainfall events more than likely have some contribution from increasing atmospheric water vapor, and were exacerbated by slower than average TC motion after landfall. Atmospheric water vapor, as measured in the form of precipitable water, has been trending upward as documented in a number of recent studies. While slower than average TC motion around and immediately following landfall also appears to be a factor in the majority of prolific TC rainfall events since 2005. Understanding these climatological/meteorological characteristics, when combined with demographic and land use/development data, support the need for a multivariate assessment of risk and vulnerability ahead landfalling tropical systems. We will describe how developing tools and methods for these events may enhance forecast confidence and aid message consistency.