This is associated with the severe storm that has since weakened, and is a heavy downpour moving into Alexandria. As the storm passed over Dulles Airport around 3:30 p.m., it produced 1 inch of rain in 30 minutes and a 66 mph wind gust.
Update 4:18 p.m. — A strong thunderstorm is heading through Annandale and Bailey’s Crossroads, toward Alexandria, but is no longer severe. More showers and storms are forming north of D.C., in southern Montgomery County.
The main threats right now are heavy rains and gusty winds.
Update 3:50 p.m. — A flood warning is in effect for southeastern Loudoun County and northwestern Fairfax County until 6:45 p.m.
Due to the storm’s slow forward speed, up to two inches of rain has already fallen in these areas, including Fairfax, Dulles International Airport, Oakton, Chantilly, Wolf Trap and Fairfax Station.
Update 3:18 p.m. — A severe thunderstorm warning is in effect for Fairfax City, west central Arlington County, Falls Church and central Fairfax County. A severe thunderstorm over Chantilly at 3:16 p.m. is moving southeast at 15 mph, packing winds as high as 60 mph, very heavy rain and frequent lightning.
Arlington, Annandale, Springfield, Herndon, Tysons Corner are all in the path of this storm. If it continues to hold together it will arrive in Alexandria around 4 p.m.
Update 3:03 p.m. — Severe thunderstorm warning in effect for southeastern Loudoun and northwestern Fairfax counties
Radar shows a severe thunderstorm with potentially damaging winds of up to 60 mph located near Dulles Airport, moving slowly southeast. It is likely to impact western suburbs of the District by 4 p.m., and possibly the immediate D.C. area by 5 p.m. if it holds together.
Scattered showers and a couple of isolated severe storms will be possible through early evening across the D.C. metro area. Storms first fired over the mountains to our west around 2 p.m., slowly chugging eastward. Storms are capable of producing gusty winds, small hail, and heavy downpours. There is a risk of localized flash flooding thanks to slow-moving storms in a moisture-rich air mass.
Additional showers and thunderstorms can be expected throughout this evening, although not everybody will get them. The bulk of the activity will wind down around sunset, though an isolated shower or storm can’t be ruled out overnight.
Rain chances taper over the weekend with clear skies on Sunday.