The National Weather Service in Sterling Virginia has issued a * Flash Flood Watch for portions of central Maryland, north central Maryland, northeast Maryland and northern Maryland, including the following areas: in central Maryland, Central and Southeast Howard, Central and Southeast Montgomery, Northwest Howard and Northwest Montgomery. In north central Maryland, Carroll and Frederick MD. In northeast Maryland, Cecil. In northern Maryland, Northern Baltimore, Northwest Harford, Southeast Harford and Southern Baltimore. * Until 2 AM EDT Thursday. * Showers and scattered thunderstorms are expected tonight. Average rainfall amounts of one-half to one inch is expected. However, thunderstorms will contain very heavy rainfall with rainfall rates around 1 to 3 inches per hour. Localized rainfall amounts of 2 to 4 inches are possible. * Heavy amounts of rain in a short period of time may cause creeks and streams to rapidly rise out of their banks as well as the potential for flash-flooding in urban areas. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. By The National Weather Service, Sterling, Va.