I know this is not DC- but I am basically on the same latitude and at low elevation- and I can think of 3 warning level events right off the top of my head in the last 2 Nina winters. The one in March I think did have some blocking, but the other 2 didn't. They were both coastal scrapers with 10" plus at the beaches, about 6 here, and little to nothing for DC. Just dumb luck I suppose.
eta- being further East/NE does help in a Nina with catching the edge of a Miller B sometimes. Happened here in Dec 2010 (the storm never to be mentioned). Got 5" or so from that, and there was 10+ a few miles to my east, but that period did feature a -NAO IIRC.