Millions of residents across the Southern Plains, Gulf Coast, and Ohio Valley are under flood watches, with urban flooding and impassable roads being key concerns. Areas like southeast Louisiana, southern Mississippi, and parts of Texas are at risk for structural flooding. In the Ohio Valley and Appalachians, recent rainfall has primed soils for flash flooding, even with moderate additional rain. The NWS warns that flash floods can develop quickly, posing significant risks to life and property.