National Weather Service United States Department of Commerce

Severe Thunderstorm Threat From the Central Plains to the Northeast; Extreme HeatRisk for the East Coast

Strong to severe thunderstorms are possible from the central Plains to the Northeast through this evening. Widespread damaging winds are the primary threat but hail and a tornado or two is also possible. Extremely dangerous heat continues across the Eastern U.S. Warm overnight low temperatures will provide little to no relief. Read More >

Heavy rain and flash flooding in Washington

Thursday afternoon September 10th 2020

 

Early on Thursday afternoon, showers and thunderstorms arose along a weak atmospheric boundary oriented north to south across the Washington area. The storms that formed were fed by tropical moisture to our southeast which allowed for heavy rainfall rates. In addition, weak winds in the atmosphere kept the storms moving slowly. That combination of heavy rain and slow movement allowed for 2-5" of rain to fall in a relatively narrow corridor across parts of the Washington metro area. Most of that rain fell within 2 hours.

The heavy rains produced flash flooding of numerous roads and streams and first responders conducted several water rescues. The hardest hit areas were: the District of Columbia, Arlington and Alexandria Virginia, and the Maryland suburbs in Prince Georges and Montgomery Counties.

 

Listing of rain totals: linked here.

Listing of reports of flooding & flash flooding (received by NWS Baltimore/Washington): linked here.


Map of radar estimated rainfall: (Areas in red are 3"+)

 

Radar Loop showing the storms from 1:25 - 1:49 P.M.

Radar loop

 

Satellite Image at 2:30 P.M.

Satellite image

 

Link to images of flooding: (using internet search "DC flooding September 2020")