Here's a listing of the AM stations that can be received at night, via skywave, in the Washington DC area. My comments are in italics.
Blue text indicates a weblink.
A 10,000 watt directional signal that makes its way to the east coast, including the Washington DC area. Occasionally heard in the Washington DC area. A directional signal with only about 700 watts to the DC area. It then switched to a talk format. Comes in weak at night in the DC area, but definitely listenable.