NWS says rain will continue across the region through at least Friday. Rain will be heavy at times, with overall additional rainfall totals of 3 to 5 inches.
NWS has just issued a Moderate flood watch for DC Metro. 3-5″ of additional rain.
— Russ Adams (@patpend) May 16, 2018
While flash flooding cannot be ruled out, the primary concern is flooding of small streams and low-lying areas, the weather service said. Streams are already elevated and soils saturated from earlier rainfall, increasing the flood threat.