Freeze Warning in Effect for Frederick (MD, VA): NWS Advisory
Official advisory issued by the National Weather Service (NOAA): * WHAT...Sub-freezing temperatures as low as 30 expected. * WHERE...In Maryland, Carroll, Frederick, Northern Baltimore, and Northwest Harford Counties. In Virginia, Culpeper, Fauquier, and Western Loudoun Counties. * WHEN...Until 9 AM EDT Sunday. *.