* WHAT. Flash flooding caused by excessive rainfall is possible. * WHERE. District of Columbia, in Maryland, including the following areas, Anne Arundel, Central and Southeast Howard, Central and Southeast Montgomery, Northwest Howard, Northwest Montgomery, Prince Georges and Southern Baltimore, and in northern Virginia, including the following areas, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park, Eastern Loudoun, Fairfax and Northwest Prince William. * WHEN. From noon EDT today through this evening. * 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. Low-water crossings may be flooded. * ADDITIONAL DETAILS. - Multiple rounds of heavy showers and thunderstorms will move across the area today into this evening. Rainfall amounts of 1 to 2 inches are likely, with isolated amounts of 3 to 4 inches possible. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information

* WHAT. Up to one half foot of inundation above ground level in low lying areas due to tidal flooding. * WHERE. Shoreline in Anne Arundel County. * WHEN. Until 9 AM EDT this morning, especially around the time of high tide. * IMPACTS. At 2.8 feet, flooding of some of the parking area near Dock Street in Annapolis may occur, with water surrounding the Alex Haley Memorial. * ADDITIONAL DETAILS. Tides one to one and a half feet above normal. The next high tide at Annapolis U.S. Naval Academy is at 5:09 AM.

* WHAT. Southwest winds 10 to 15 kt with gusts up to 20 kt expected. * WHERE. Chesapeake Bay from Sandy Point MD to Drum Point MD, Tidal Potomac from Cobb Island MD to Smith Point VA, Eastern Bay, and Choptank River to Cambridge MD and the Little Choptank River. * WHEN. From 2 AM to noon EDT Thursday. * IMPACTS. Conditions will be hazardous to small craft.