The area National Weather Service Offices put out a product that displays potential snowfall for an upcoming event. Often times it is these forecasts that are included in weather apps or some local TV broadcasts. It is one of many resources to use.
Here is a look at the official forecast for snow, followed by the high and low end, and ice potential when available. These come from the National Weather Service Offices in Sterling, VA, State College PA, and Mount Holly , NJ.
The maps here include snow or ice forecast for Maryland, Pennsylvania, West Virginia, Virginia, Delaware, and New Jersey.
Expected Snowfall Or Ice for Maryland
From The National Weather Service Baltimore/Washington in Sterling, VA.