You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.

A wavy slow moving frontal system will meander about the area on Friday evening into the night. Anomalous moisture coupled with high rainfall rates should increase the risk of flash flooding over portions of this watch area... * WHAT...Flash flooding caused by excessive rainfall is possible. * WHERE...District of Columbia, Maryland, including the following areas, Anne Arundel, Calvert, Carroll, Cecil, Central and Southeast Howard, Central and Southeast Montgomery, Charles, Frederick MD, Northern Baltimore, Northwest Harford, Northwest Howard, Northwest Montgomery, Prince Georges, Southeast Harford, Southern Baltimore and St. Marys, and Virginia, including the following areas, Albemarle, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park, Culpeper, Eastern Loudoun, Fairfax, Greene, King George, Madison, Nelson, Northern Fauquier, Northwest Prince William, Orange, Rappahannock, Southern Fauquier, Spotsylvania, Stafford and Western Loudoun. * WHEN...From Friday evening through late Friday night. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS... - As a wavy slow moving frontal system tracks across the area, multiple rounds of showers and thunderstorms are possible. While initially posing a severe weather threat, a shift to a slow moving complex of moderate to heavy rain unfolds into the evening and night. Storm totals could reach 2 to 3 inches, locally nearing 4 inches in spots. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information