The last in a long train of storms will bring snow and ice to the Mid-Atlantic and Carolinas on Wednesday. While Washington will be near the northern edge of the storm starting late in the morning — with a dusting to a half-inch of snow possible in the District and areas to the south by the evening — impacts will be moderate to major farther south.

Officials urged people to stay off the roads Wednesday in portions of Virginia and North Carolina where a storm dropped heavy snow and caused hundreds of accidents in places unaccustomed to significant accumulations.

Nearly 5,600 flights were canceled or delayed across the U.S., including more than 400 in and out of Charlotte Douglas International Airport in North Carolina, according to the flight-tracking