Tornado Watch Continues Until 2AM for DC Area

The DC Metro area is under a tornado watch until 2am. A tornado watch means that conditions are favorable for the possible formation of tornadoes and severe thunderstorms.

Update: WJLA has this photo of a tornado that touched down in Stafford County.

The NWS Storm Prediction Center has issued a
Tornado Watch for portions of 

       District of Columbia
       Maryland
       northern North Carolina
       central and eastern Virginia
       eastern West Virginia
       coastal waters

Effective this Wednesday night and Thursday morning from 615 PM
until 200 am EDT.

Tornadoes...hail to 2 inches in diameter...thunderstorm wind
gusts to 70 mph...and dangerous lightning are possible in these
areas.

The Tornado Watch area is approximately along and 70 statute
miles east and west of a line from 15 miles northeast of
Martinsburg West Virginia to 30 miles west southwest of Raleigh
North Carolina.  For a complete depiction of the watch see the
associated watch outline update (wous64 kwns wou0).

Remember...a Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

Discussion...tstms have rapidly intensified this evening within a
moist and moderately unstable environment with MLCAPE values of
1000-2000 j/kg.  Deep-layer vertical shear is already supportive of
supercells...and low-level shear is forecast to strengthen through
the remainder of the evening with effective srh values approaching
250-300 m2/s2.  As such...the potential for tornadoes will exist in
addition to damaging winds and hail.