While they dig out from an epic snowstorm on Friday and Saturday, road crews and utility workers across the Mid-Atlantic States may be facing a Sisyphean struggle. They are likely to be digging out all over again after another heavy snowfall that is forecast to start Tuesday afternoon.

The National Weather Service in Sterling, Va., issued a winter storm warning for the region, predicting as much as 20 inches of additional snow, with strong winds and hazardous travel conditions, before the storm passes on Wednesday. The chilly tempest, arriving out of the South and the West, is expected to move up along the East Coast and strike New York City and its suburbs around midnight Tuesday, with 6 to 12 inches of powder.

Until that warning, the news on Monday was mostly upbeat, as the sun shone on the thick blanket of snow covering Washington, Philadelphia, Baltimore and the dense suburban nexus around and between them.

Karyn Le Blanc, a spokeswoman for the District of Columbia Department of Transportation, reported that freeways and major boulevards like Constitution Avenue and Pennsylvania Avenue were all passable, and that crews were trying to get as much done as they could before Tuesday afternoon, when the next heavy snowfall is expected.

“Now that we’ve made the roads passable, we’ll have to make them passable again,” Ms. Le Blanc said.

Cheers for snow-removal workers were heard in some side streets around Washington once the way was clear and trapped residents were mobile once more. On a street in Bethesda, Md., near the District of Columbia line, neighbors brought out home-baked goods to thank the workers who scraped the block clean despite a four-inch layer of solid ice.

Some streets in southern New Jersey were still packed with snow and slippery on Monday morning. Atlantic Electric said that as many as 44,000 of its customers — about 7 percent of the total — were still without power, mostly in Cape May County, the southernmost part of the state.

The snow did seem to stifle somewhat the appetite for gambling at Atlantic City’s casinos, which were quick to get back in full operation but had fewer players. The snow was an added blow to what was already a slow season, but the casinos expressed hope that the coming holiday weekend would be strong.

Atlantic City officials reported that coastal erosion from the storm swept a lot of sand from the beaches between Connecticut Avenue and Virginia Avenue, along the central part of the Boardwalk. When the weather gets warm enough, beachgoers may have less room to sunbathe.