(Updated at 10:30 p.m.) The region is under a Severe Thunderstorm Warning through 11:15 p.m. Forecasters say a line of powerful storms known as a derecho is quickly moving our way from the Ohio Valley.

From the National Weather Service:

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING…

* UNTIL 1115 PM EDT

* AT 1009 PM EDT… SEVERE THUNDERSTORMS WERE DETECTED ALONG A LINE EXTENDING FROM 7 MILES NORTHEAST OF BRUNSWICK TO OATLANDS TO 10 MILES SOUTH OF BEALETON TO 25 MILES WEST OF MASSAPONAX… AND WERE MOVING EAST AT 60 MPH. THIS LINE OF STORMS IS CAPABLE OF PRODUCING HAIL UP TO THE SIZE OF QUARTERS AND DESTRUCTIVE WINDS IN EXCESS OF 80 MPH.

* LOCATIONS IMPACTED INCLUDE… HARRY GROVE STADIUM… SOUTH RIDING… LANSDOWNE… BROADLANDS… POOLESVILLE… HERNDON… DULLES INTERNATIONAL AIRPORT… COUNTRYSIDE… LOWES ISLAND… GREEN VALLEY…

THIS IS A DANGEROUS LINE OF STORMS. IF YOU ARE IN ITS PATH… MOVE INDOORS TO A STURDY BUILDING AND STAY AWAY FROM WINDOWS. WHEN IT IS SAFE TO DO SO… REPORT SEVERE WEATHER TO LOCAL LAW ENFORCEMENT OR TO THE NATIONAL WEATHER SERVICE.

THIS LINE OF STORMS HAS A HISTORY OF PRODUCING WIDESPREAD WIND DAMAGE. SEEK SHELTER INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS.

Also:

SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS TO IMPACT REGION THIS EVENING…

AT 745 PM… A LINE OF SEVERE THUNDERSTORMS PRODUCING DAMAGING WIND GUSTS WAS CROSSING SOUTHEAST PENNSYLVANIA AND CENTRAL WEST VIRGINIA. THIS LINE OF THUNDERSTORMS IS EXPECTED TO HIT THE POTOMAC HIGHLANDS BETWEEN 8 AND 8:30 PM… THE SHENANDOAH VALLEY BETWEEN 8:30 AND 9 PM… THE INTERSTATE 95 CORRIDOR INCLUDING THE GREATER WASHINGTON AND BALTIMORE METROPOLITAN AREAS BETWEEN 9:30 AND 10 PM… THEN REACHING THE CHESAPEAKE BAY BETWEEN 10:30 AND 11 PM.

THIS LINE OF STORMS HAS A HISTORY OF PRODUCING MAJOR WIND DAMAGE ACROSS WEST VIRGINIA DUE TO WIND GUSTS OVER 75 MPH… ALONG WITH PROLIFIC CLOUD TO GROUND LIGHTNING.