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Posted at 12:30 PM ET, 04/28/2011

Tornado watch east and southeast of D.C. through 3 p.m.

Watch discontinued from D.C. west

12:30 p.m. update: Tornado watch canceled except east and southeast of District. See map of where it remains active. However, even in our eastern suburbs the threat is now greatly diminished.

12:00 p.m. update: Some scattered thundershowers are flaring up east and southeast of D.C. but to the northwest precipitation has largely ended. The Flash Flood Watches in effect for the metro region mentioned below have been dropped but flash flood warnings remain in effect until 12:30 p.m. to the northwest (described below)

11:45 a.m. update: The tornado warning for Anne Arundel county has been discontinued and the storms are crossing the Bay. This storm outbreak is just about over.

11:15 update:The tornado watch has been trimmed back and now no longer includes Frederick, Loudoun and Fauquier counties

Overview: Since just after 2 p.m. yesterday, the metro region has been under a tornado watch. By the time the latest Tornado Watch expires at 3 p.m. (unless it’s canceled early), it will have run for more than a full day, longer than I have ever witnessed in this region. NOAA’s Storm Prediction Center indicates there is a moderate (40%) probability of two or more tornadoes in the watch area.

A Flash Flood Watch also covers the region through 3 p.m. and a Flash Flood Warning is in effect through 12:30 p.m. for eastern Loudoun county, western Montgomery county and eastern Frederick county. In the warning area, one to two inches of rain has already fallen and another inch or so is possible. In the watch area, downpours through this afternoon may be sufficiently heavy to cause flash flooding as the storms are slowing down as they move east.

What to expect (last updated 8:35 a.m. and 10:55 a.m.): Thunderstorms, some rotating, will continue moving from southwest to northeast through the metro region. Much of the activity has tracked through the far western suburbs this morning - from Fauquier county into Loudoun, eastern Frederick and western Montgomery county up into Carroll county. As the morning wears on, storms developing to the southwest should target the immediate metro region and then the eastern suburbs by late morning to midday. Torrential rain, damaging winds and small tornadoes are possible in storms moving through. Large tornadoes, like those that devastated the South, are not anticipated.

Storm History: The storm produced reports of tornadoes in Prince William and Prince George’s county last night. Funnel clouds have been reported in Frederick, Spotsylvania, Stafford, Howard, Prince George’s and Charles counties. See also this story: Funnel clouds reported throughout region, but little damage

Monitor severe warnings issued by the National Weather Service and radar on our Severe Weather Tracking Station below. Also, comment below with conditions where you are.

Severe Weather Tracking Station
Warning Text: DC | MD | VA * NWS Local Storm Reports
Radar & Lightning: Movement of precipitation and lightning strikes over past two hours. Refresh page to update. Click here to see radar bigger.
    
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Warnings: Severe alerts from National Weather Service. Updates w/o refresh (most browsers). Hint: Alert on map? Click matching label in key for details.

Keep reading for earlier updates...

11:25 a.m. update: TORNADO WARNING for Anne Arundel county until noon. At 11:19 AM radar indicated tornado near Rhode River, moving NE at 65 mph. Severn River is in path. Seek shelter.

11:20 update: Line of storms from Annapolis to Leonardtown along Bay is really nasty, but weather is dramatically improving to the west - though some scattered thundershowers linger.

11:00 a.m. update: A new severe thunderstorm warning has been issued until noon for St. Mary’s, southern Charles, and southern Calvert counties. Damaging winds are possible with this storm. West of I-95, activity continues to diminish to the west but scattered thundershowers with downpours and gusty winds remain.

11:10 update: Another severe thunderstorm warning for the eastern suburbs is out until 11:45 a.m. for Anne Arundel (except north part of county), northern Calvert and eastern Prince George’s counies. It includes Annapolis. Damaging winds are the main threat with this storm.

10:40 a.m. update: The severe thunderstorm threat is now rapidly shifting to east of I-95. A severe thunderstorm warning has been issued for southern Anne Arundel, Calvert, southern Charles, southern Prince Georges, and northern St. Marys counties until 11:30 a.m. Winds in excess of 60 mph are possible with this storm along with very heavy downpours. Locations to be impacted include: Port Tobacco River, Prince Frederick, and Chesapeake Beach. West of I-95 coverage and intensity of showers and thunderstorms is diminishing.

10:20 a.m. update: Severe thunderstoms have moved out of Montgomery county and, aside from the storm down in Stafford (see below), no severe thunderstorm or tornado warnings are in effect. Nonetheless, strong storms are rapidly racing north through central Fairfax county and eastern Prince William county and should move into the eastern Montgomery county and the District in the next 30 minutes. Heavy downpours and gusty winds are likely.

10:05 a.m. update: The flash flood warning area has been expanded into the northern suburbs covering northwest Montgomery county and Frederick and Carroll counties through 12:30 p.m. Also, a severe thunderstorm warning has been posted for southern Stafford county (and south of Fredericksburg through Spotsylvania and east into King George county) until 10:45 a.m..

9:50 a.m. update: Flash flood warnings have been issued for west central Montgomery, east central Fauquier, southeast Loudoun, northwest Prince William and northwest Fairfax county. From NWS:

BRIEF VERY HEAVY RAINFALL...OVER AN INCH IN AN HOUR IN SOME LOCATIONS...HAS OCCURRED FROM NEAR HAYMARKET TO STERLING...AND MOVING INTO MONTGOMERY COUNTY. FLASH FLOODING IS LIKELY DUE TO THE EXTREMELY HIGH RAINFALL RATE.

9:45 a.m. update:A severe thunderstorm warning has been issued for eastern Loudoun, western Fairfax, central Montgomery county and southern Howard county until 10:15 a.m. Severe thunderstorm near Dulles moving NE at 60 mph. Damaging winds exceeding 60 mph possible with storm. Great Falls, Potomac, Rockville, Olney in path

9:25 a.m. update: Tornado warning canceled for northern Montgomery county, remains in effect elsewhere noted below.

9:15 a.m. update: TORNADO WARNING for extreme northern Montgomery county, eastern Frederick, extreme western Howard, and south central Carroll county until 9:45 a.m.. Potential tornadic storm near Damascus at 9:09 AM moving NE at 45 mph toward Mount Airy, Eldersburg, Gamber, Westminster, Hampstead, Manchester

9:00 a.m update: Now for some good news: The back edge of the showers and storms is closing in on the metro region. See regional radar. Because the front is slowing down as it approaches, it will take a few hours to clear - especially in the eastern suburbs. But there is light at the end of this LONG tunnel.

8:50 a.m update: A TORNADO WARNING is in effect for northern Carroll and northwest Baltimore county until 9:15 a.m. (map)

8:45 a.m. update: For the moment (and it’s not likely to last long), no tornado or severe thunderstorm warnings are in effect. But a large area of showers and storms have arrived in Fauquier county and should move into Prince William, Loudoun, Fairfax, and Montgomery county in the next hour.

8:12 a.m. update: New TORNADO WARNING for eastern Frederick county and southern Carroll county until 8:45 a.m. Doppler radar indicated a severe thunderstorm capable of producing a tornado 6 miles south of Ballenger creek...or 10 miles south of Frederick...moving northeast at 45 mph. Locations impacted include New Market, Green Valley, Mount Airy, Westminster, Gambler. Take cover if you’re in the vicinity of these areas.

8:10 a.m. update: At 8:05 a.m. doppler indicated tornado was located 7 miles east of Westminster, moving northeast at 55 mph toward rural northwestern Baltimore county. Tornado warning discontinued for Frederick county.

8 a.m. update: Tornado warning until 8:45am for portions of Carroll, Frederick and Baltimore counties.

By  |  12:30 PM ET, 04/28/2011

Categories:  Thunderstorms

 
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