Environmental Contributors to the Development, Expansion, and Intensification of the 2012 Central United States Flash Drought

During 2012, flash drought developed and expanded across large areas of interior North America with severe impacts to overall water resources and warm-season agricultural production. Recent efforts have yielded a methodology to detect and quantify flash drought occurrence, development, and intensification from climatological datasets via the standardized evaporative stress ratio (SESR). This study utilizes the North American Regional Reanalysis (NARR) and applied the SESR methodology to quantify the spatial and temporal development and expansion of the flash drought conditions during 2012. Critical results include the identification of the flash drought epicenter and subsequent spread of flash drought conditions radially outward with varying rates of intensification. Further, SESR analyses were compared with additional environmental factors that played critical roles including (1) large-scale forcings that drove precipitation deficits along with enhanced solar radiation, vapor pressure deficits, and surface temperature conditions and (2) local surface-atmosphere coupling that produced a hostile environment for the formation of deep-convection and exacerbated the depletion of soil moisture and vegetation desiccation. These analyses demonstrate that enhanced early-season temperatures and vegetation growth were critical to the rapid onset of flash drought once large-scale forcings began to limit precipitation and increase evaporative demand. Subsequent land-atmosphere coupling then perpetuated the flash drought development and enhanced the radial spread of flash drought conditions across large regions.