Spatiotemporal Patterns of Drought/Tropical Cyclone Co-occurrence in the Southeastern USA: Linkages to North Atlantic Climate Variability.

Droughts and landfalling tropical cyclones (TCs; tropical depressions, tropical storms, and hurricanes) are important features of the hydroclimate of the southeastern USA at seasonal, interannual, and interdecadal scales. The societal impacts and climatological aspects of both droughts and Atlantic TCs have been widely addressed in the scientific literature. However, in general, previous research has assessed the two phenomena separately. Recently, the spatiotemporal patterns and hydroclimatic impacts of drought amelioration by landfalling TCs have been analyzed for the southeastern USA, as well as the large-scale dynamic forcing mechanisms that enhance or suppress drought-TC co-occurrence. At multidecadal time scales, both droughts and TCs in this region vary in association with several leading modes of basin-wide and regional climate variability. These climate modes appear to be coherently linked to a background oceanic-atmospheric pattern that either promotes or suppresses the likelihood of both droughts and TC landfalls. The relative frequency of TC landfalls in drought-stricken areas, the importance of these events in the regional moisture budget, and the potential for future changes in the large-scale forcing environment raise fundamental questions about possible changes in the hydroclimate of the southeastern USA, where population growth and rising water demand already place strain on freshwater resources. In this article, we provide a review and synthesis of the recent research on variability in drought, landfalling TCs, the characteristics of the space-time association between these two phenomena in the southeastern USA, and the coherent large-scale oceanic-atmospheric environment that either promotes or suppresses their co-occurrence. Further, we review Global Climate Model projections related to these factors, and we identify avenues for future research on this important topic. [ABSTRACT FROM AUTHOR]