It includes Frederick County, surrounding jurisdictions.

...FLOOD WATCH REMAINS IN EFFECT THROUGH LATE TONIGHT...
* WHAT...Flooding caused by excessive rainfall continues to be
possible.
* WHERE...Portions of Maryland, northern Virginia and panhandle West
Virginia, including the following areas: in Maryland, Carroll,
Cecil, Frederick MD, Northern Baltimore, Northwest Harford and
Washington. In northern Virginia, Western Loudoun. In panhandle
West Virginia, Berkeley, Jefferson and Morgan.
* WHEN...Through late tonight.
* IMPACTS...Excessive runoff may result in flooding of rivers,
creeks, streams, and other low-lying and flood-prone locations.
Creeks and streams may rise out of their banks. Flooding may occur
in poor drainage and urban areas.
* ADDITIONAL DETAILS...
- Multiple rounds of scattered to numerous showers and
thunderstorms are likely this afternoon and tonight. The most
likely time period for thunderstorms producing heavy rain and
potential flash flooding is this evening into the overnight,
but thunderstorms could develop as early as this afternoon.
Several inches of rain are possible in a short period of
time, which would cause rapid rises of water.
- http://www.weather.gov/safety/flood
PRECAUTIONARY/PREPAREDNESS ACTIONS...
You should monitor later forecasts and be alert for possible Flood
Warnings. Those living in areas prone to flooding should be prepared
to take action should flooding develop.
By The National Weather Service, Sterling, Va.