Very heavy rain is impacting that region and much of the area as we head toward midnight. Moderate to heavy rain falling more often than not should be the story from here through the sunrise period or so. From earlier…We’ve got a rare and potentially dangerous heavy rain event developing over the region tonight. Rain will be steadily falling through the overnight period, with several bursts of heavy or torrential rain and thunder embedded within the main rain shield. Some scattered thunderstorms with bursts of heavy rain will develop in the late afternoon.

Source: Washington Post July 28, 2017 20:44 UTC