Places recently hit hard -- like Kerrville, Texas, and Burnet, Texas -- are inside this heightened potential for flash flooding, with any heavy rain and flash flooding that occurs over or adjacent to these areas likely to flow downstream via rivers that run through or nearby these devastated areas.

Another round of showers and thunderstorms moved across the Mid-Atlantic Tuesday after intense rain set off dangerous flash flooding from Virginia to New York on Monday, leaving at least two dead and prompting dozens of rescues as water overwhelmed roads and subways.