There's a Winter Weather Advisory in effect for Baltimore City, southern Baltimore County, and Howard County. Much of the rest of the area's under a Winter Storm Warning, including northern Baltimore County and Harford, Carroll, Frederick, and Washington counties.
The forecast's prompted a number of schedule changes.
The Social Security Administration Headquarters and its Baltimore Metro Area Offices will open 2 Hours late. And there's a liberal leave policy in effect for Baltimore County employees; similar policies are in effect for several other county governments.
Some issues for MARC trains; Brunswick Line trains are operating 10-20 minutes late. And there are additional delays around the system... you can find out more here.
Some colleges and private schools are also changing their schedules; be sure to make sure your destination will be open before you head out.