* WHAT. Flash flooding caused by excessive rainfall is possible. * WHERE. The District of Columbia, and portions of Maryland, including the following areas, Anne Arundel, Carroll, Central and Eastern Allegany, Central and Southeast Howard, Central and Southeast Montgomery, Charles, Eastern Garrett, Extreme Western Allegany, Frederick MD, Northern Baltimore, Northwest Harford, Northwest Howard, Northwest Montgomery, Prince Georges, Southeast Harford, Southern Baltimore, Washington and Western Garrett, Virginia, including the following areas, Albemarle, Arlington/Falls Church/Alexandria, Augusta, Central Virginia Blue Ridge, Central and Southeast Prince William/Manassas/Manassas Park, Clarke, Culpeper, Eastern Highland, Eastern Loudoun, Fairfax, Frederick VA, Greene, King George, Madison, Nelson, Northern Fauquier, Northern Virginia Blue Ridge, Northwest Prince William, Orange, Page, Rappahannock, Rockingham, Shenandoah, Southern Fauquier, Spotsylvania, Stafford, Warren, Western Highland and Western Loudoun, and West Virginia, including the following areas, Berkeley, Eastern Grant, Eastern Mineral, Eastern Pendleton, Hampshire, Hardy, Jefferson, Morgan, Western Grant, Western Mineral and Western Pendleton. * WHEN. Through 2 AM tonight. * IMPACTS. Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS. - Showers and thunderstorms will form this afternoon and linger on and off through the first half of the night. Storms will be slow moving and capable of producing very heavy rainfall. Rainfall totals of 1 to 2 inches appear likely for locations that receive thunderstorms, with isolated totals of 2 to 4 inches. The strongest thunderstorms may be capable of producing 1.5 to 2.5 inches of rain in an hour. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information

* WHAT. Flash flooding caused by excessive rainfall is possible. * WHERE. A portion of central Pennsylvania, including the following areas, Adams, Bedford, Blair, Cambria, Cameron, Clearfield, Columbia, Cumberland, Dauphin, Franklin, Fulton, Huntingdon, Juniata, Lancaster, Lebanon, Mifflin, Montour, Northern Centre, Northern Clinton, Northern Lycoming, Northumberland, Perry, Potter, Schuylkill, Snyder, Somerset, Southern Centre, Southern Clinton, Southern Lycoming, Sullivan, Tioga, Union and York. * WHEN. Through late tonight. * IMPACTS. Creeks and streams may rise out of their banks. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS. - Very heavy rainfall is expected today from numerous, slow- moving thunderstorms. The rain and already wet ground in many locations will cause smaller creeks and streams to flood quickly. - http://www.weather.gov/safety/flood