...A tropical air mass remains over the area which will lead to intense rainfall rates, particularly where cells are slow moving... * WHAT...Flash flooding caused by excessive rainfall continues to be possible. * WHERE...Portions of western Maryland, including the following areas, Central and Eastern Allegany, Eastern Garrett and Extreme Western Allegany, Virginia, including the following areas, Albemarle, Augusta, Central Virginia Blue Ridge, Culpeper, Eastern Highland, Frederick, Greene, Madison, Nelson, Northern Virginia Blue Ridge, Orange, Page, Rappahannock, Rockingham, Shenandoah and Warren, and West Virginia, including the following areas, Berkeley, Eastern Grant, Eastern Mineral, Eastern Pendleton, Hampshire, Hardy, Morgan and Western Mineral. * WHEN...Through this evening. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS... - A persistent pattern continues with a tropical air mass in place and a frontal zone remains nearby. Thunderstorms may be slow moving at times and some areas will see multiple rounds of storms. Given recent heavy rainfall during the past couple days, tropical downpours will increase the risk of flash flooding this afternoon and evening. Rainfall rates could approach 2 to 3 inches per hour in the stronger cells. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information.