Arlington and the rest of the D.C. area is under a Severe Thunderstorm Watch.
A line of storms is expected to reach the area around 5 p.m. The watch is in effect until 10 p.m.
From the National Weather Service:
A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR THE ENTIRE OUTLOOK AREA UNTIL 10PM. THE MAIN THREAT IS DAMAGING WIND. LARGE HAIL AND ISOLATED TORNADOES ARE POSSIBLE.
TORRENTIAL DOWNPOURS MAY LEAD TO LOCALIZED FLASH FLOODING OF STREAMS…CREEKS AND URBAN AREAS.