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.

A flood watch was in effect for more than a dozen counties as authorities resumed the search for victims of the July 4 tragedy.

Earlier Monday, the National Weather Service (NWS) for San Antonio warned that a "dangerous situation is occurring" in areas of Texas.