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Posted at 12:00 AM ET, 09/09/2011

Dangerous flooding continues to plague portions of metro region

More moderate to heavy rain possible overnight

Flood warnings throughout metro region overnight (except northeast suburbs)
Map: Today’s accumulated rainfall

Road/traffic conditions: Dr Gridlock | Hurricane Tracking Center
More storm impacts: Post Local | Submit/view storm pics

12:00 a.m. update: While we had a brief burst of moderate rain in the District and inside the beltway, rainfall intensity has started to wane again. In a bit of good news, flood warnings have been lifted northeast of D.C.

Heavy rains remain over the northern neck of Va., but - thus far -haven’t made a lot of progress northward. For the remainder of the night, we’ll probably see rain of varying intensity as well as some breaks in the action. While I cannot rule out some more locally heavy rain and flooding, the worst is likely over for tonight.

Be prepared for a messy morning commute. Allow plenty of time.

11:00 p.m. update: Moderate rain has redeveloped over the metro region and covers the District. With a long train of moisture to the south, this may continue for at least a few more hours, with another 1-2 inches of rain possible.

10:00 p.m. update: A good portion of the immediate metro region is getting a break from moderate to heavy rain (light rain continues in many places), although some moderate rain is impacting the eastern suburbs from eastern Prince George’s county to the Bay. Some heavier rain over southern Prince William county into the northern neck of Va. seems to be hitting some resistance as it moves north and northwest. However, it is likely that moderate to even heavy rain resumes in the District and especially the western suburbs (including Fairfax county) overnight. We will keep you posted.

8:40 p.m. update: Flash flood warnings have been extended until 12:30 a.m. for the District, Arlington, southeast Montgomery county, western Prince George’s county, Falls Church and Howard county, where 1-2” of additional rain is forecast. While we’ve focused on the historic rainfall exceeding 10-15” in southern Fairfax county (where it keeps raining by the way), such totals have also mounted in southern Charles county - where it also keeps raining, and heavily. It’s this slug of heavy rain over Charles county and extending south into the northern neck of Virginia which looks to move north, exacerbating flooding conditions throughout the D.C. metro region overnight.

Earlier updates

Overview (from 3:40 p.m.): Steadily today, the axis of heavy rain shifted from D.C.’s eastern suburbs to the western suburbs. Torrential rains, falling at rates of 1-3” an hour affected Springfield, Falls Church, east Fairfax, McLean, and Potomac this morning into the early afternoon. Since mid-afternoon, these rains have moved into Manassas, Centreville, west Fairfax, Reston (reports of 4-5” there today), Oakton, Great Falls, north Rockville and to the northwest towards northeast Loudoun, western Montgomery and southeast Frederick counties. Flash flooding has closed many roads in these areas and there are reports of stranded vehicles and water rescues.

Heavy rain showers capable of flash flooding will continue overnight throughout the region and have resumed over eastern Fairfax county, the District and points east. And more rain showers capable of localized flooding are likely Friday, but less heavy and widespread than today.

Through Tonight: Heavy, driving rain capable of flash flooding is likely in central Prince William, western Fairfax, eastern Loudoun, western Montgomery and central and eastern Frederick counties through the evening commute. That activity may slowly drift towards western Prince William, central Loudoun and western Frederick county later this evening before diminishing in coverage and intensity. However, additional heavy showers and storms building to the southeast may create new flooding problems in eastern Fairfax county, the District and eastern suburbs. Later tonight, the rain may decrease some, but the risk of heavy downpours capable of flash flooding persists. Lows will range from 65-70.

Tomorrow (Friday): Widespread showers are likely intermittently, with the greatest concentration west of the District. Brief downpours are possible anywhere, and may be enough to prompt additional flooding. Highs will be in the mid-70s to near 80.

See David Streit’s forecast through early next week. And if you haven’t already, join us on Facebook and follow us on Twitter

Flooding photos: Georgetown Pike (@danhallie) | Reston parking lot (@restonpatch) | Picket Road and Old Lee Highway (@bethb324) | Lower portion of Reston North Park and Ride | Rt 50 in Fairfax (@alliecat827, near intersection with Toyota Dealership, Hooters, etc) | Sunset Hills Rd Reston 1 (@OhioFan07) | Rt 7 and Colvin Run | I-495S at Old Dominion Dr. (@GregCypes) | Rt 7 at Dranesville Rd. | Beulah Rd and Browns Mill in Vienna (wassupsWords) | Strayer University in Alexandria at 8 p.m.

Keep reading for flooding videos....

Video of man tubing down Rt 29 in Fairfax into oncoming traffic. Very ill-advised and dangerous.

Flooding on a Fairfax street

Video of flooding in Chantilly at Big Rocky Run west of Stringfellow, behind Poplar Tree Elem. (from David Schuetz)

Flood video at Four Mile Run at Carlin Springs in Arlington | Another Four Mile Run video

Earlier updates:

8:00 p.m. update:The rain in southern Fairfax county is tireless and the amounts are staggering. Places like Lorton, Newington and Fort Belvoir (which has received 7” in last three hours) have seen 10-15” or more of rain this week (much of it today) and it shows no signs of stopping, even if the intensity wanes slightly

7:25 p.m. update: Torrential rain continues, particularly in southern Fairfax county, southeast Prince William county, and southern Charles county. Road closures have been reported in Falls Church city, and a section of the beltway has been shutdown in both directions over Cameron Run due to high water. Flash flood warnings have been extended for the western suburbs through 11:00 p.m. Areas currently experiencing heavy rain may not see signficant improvement until after midnight. Rain is not moving quickly. This may have some in­cred­ibly bad consequences.

6:45 p.m. update: Some rainfall totals in southern Fairfax county in just the last hour have been 3-4”! Image.

6:30 p.m. update: Excerpt from National Weather Service technical discussion re: extreme rainfall rates for eastern Fairfax county and District:

A threat for heavy rainfall...with rates around 2 in/hr...will continue into the early evening. ... The primary area of concern will extend from montgomery county into wrn portions of the dc area and farther outh into portions of fairfax and prince william counties.

6:00 p.m. update: The rainfall rates right now in southern and eastern Fairfax County, including the entire western side of the beltway in Va. are dangerously high; up to 2-3” per hour. Stay off the roads if possible.

5:45 p.m.: Tornado warning in St. Mary’s & Charles co discontinued

5:30 p.m.: TORNADO Warning C CHARLES CO & NW ST. MARYS Co. Poss tornado 7 MI NE of Swan Point MOVING NW at 15 mph. Take cover now

By  |  12:00 AM ET, 09/09/2011

 
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