The remnants of Tropical Storm Lee settled in over the mid-Atlantic and Northeast on Wednesday, prompting warnings of heavy rain and flash flooding in areas from Washington up to western New England, the National Hurricane Center said. Several rounds of heavy rain lie in store for much of the region the next couple of days, with an additional 2 to 6 inches forecast -- and in isolated cases as much as 10 inches. This comes on top of the heavy precipitation that already has fallen in the region as the storm, which blew up from the Gulf of Mexico, ran up against an extra-tropical low-pressure system centered across the central Appalachian Mountains and stalled. These rains may cause life-threatening flash floods and mudslides, the prediction center said. A flash flood warning for the District of Columbia remains in effect till midnight tonight, with damaging wind gusts and severe thunderstorms also possible. A news release from the D.C. Homeland Security and Emergency Management Agency urged people to avoid driving when possible, drive very carefully when you must drive, and stay alert for pooling water that you can not drive through. Earlier Wednesday, the storm caused a series of air traffic delays across the Northeast. Multiple flights were delayed by over an hour in the New York metro area and by up to 55 minutes in Boston and Philadelphia. The forecast was unwelcome news