It will be in effect from 2 AM to 9 AM on Wednesday.
...FREEZE WARNING IN EFFECT FROM 2 AM TO 9 AM EDT WEDNESDAY... * WHAT...Sub-freezing temperatures in the lower to middle 20s. * WHERE...Portions of central and northern Maryland and central and northern Virginia west of Interstate 95, and the eastern panhandle of West Virginia. * WHEN...From 2 AM to 9 AM EDT Wednesday. * IMPACTS...Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing. PRECAUTIONARY/PREPAREDNESS ACTIONS... Take steps now to protect tender plants from the cold. To prevent water pipes from freezing, wrap or drain or allow them to drip slowly. By The National Weather Service, Sterling, Va.