Radar & lightning:Latest D.C. area radar shows movement of precipitation and lightning strikes over past two hours. Refresh page to update. Click here or on image to enlarge. Or see radar bigger on our Weather Wall.

The National Weather Service Storm Prediction Center has issued a tornado watch until 10 p.m. eastern for the entire Washington, D.C. and Baltimore metro regions. It says several tornadoes are likely in the region, as well as numerous wind gusts to 70 mph.

In addition to the tornado watch, flash flood watches and warnings are in effect for the region through into the evening for up to 1 to 3 inches of additional rainfall that could cause low lying areas to flood as well as creeks and streams.

For an explanation for what’s behind this possible episode of severe weather, see our earlier blog post: Late day thunderstorms could be severe

Link: Your photos: Heavy rain soaks D.C. region

10 p.m. update: The back edge of this evening’s main line of storms is heading east and away from the area, now approaching the Chesapeake Bay. A few showers may still pop-up over the next few hours but that’s about it. Flooding will remain a risk near creeks and streams through evening. Follow our Twitter and Facebook feeds for more updates and news as warranted. Tomorrow is warm and a bit less humid with early-morning fog possible, followed by at least partly sunny skies, highs in the mid-to-upper 80s, and a 20-30% chance of a few showers or t’showers.

9:35 p.m. update: The storms have cleared east of DC and I-95 but flooding remains a big problem across much of the area. According to @capitalclimate, “DC 0.96″ rain in past hour puts daily total over 2.5″, beating 1945 record of 2.27. 0.43 in 6 min, rate of 4.3″/hr”

9:15 p.m. update: Multiple reports of Flash Flooding across the area at this time, including Broad Branch Rd and Beach Dr in NW DC, and Cameron Run in Huntington. Meanwhile, damage from the Tornado in the Woodbine area of Howard County includes a garage collapse (see video).

9 p.m. update: The National Weather service said that a “confirmed tornado” was reported near Sykesvillle, a town in Carroll County, northeast of Damascus. The touchdown occurred about 7:20 p.m and was confirmed by state officials according to NWS. Tree an building damage were reported in Woodbine area of Howard County. See full story.

8:10 p.m. update: While areas west and northwest of Baltimore are dealing with Tornado Warnings, flooding continues to be the biggest concern with storms in the DC area at least thus far. Most of the area is under Flash Flood Warnings until around 10:30 p.m., give or take 15 minutes (see map). The National Weather Service warns that the storms coming through, now almost centered over D.C. and I-95, can produce as much as 1 inch of rain in just 30 minutes.

7:35 p.m. update: A solid line of heavy thunderstorms has reached the western branch of the Beltway and will move east across D.C. proper during the next hour. Currently there are no Severe Thunderstorm warnings. But along with dangerous lightning we do have heavy rain that has prompted Flash Flood Warnings for much of Fairfax County including the City of Fairfax, and central Prince William County including Manassas. Be very careful if driving in these areas. Turn around, don’t drown.

Tornado Warning until 7:30 p.m. indicated by red box.

7:05 p.m. update: TORNADO WARNING issued for far northeast Montgomery County into southern Carroll, western Baltimore and northwest Howard counties until 7:30 p.m. Locations impacted include Sykesville, Eldersburg, Oakland & Gamber. Damascus is not within the warning area

6:55 p.m. update: For the time being there remains no severe warnings in the immediate metro area as the main line of storms makes its way into the western suburbs with scattered t’storms out ahead of it. Still, most places should see a period of heavy rain and lightning, and storms could still turn severe. A new Flood Warning is in effect until 9:30 p.m. for Loudoun County and the northwest half of Montgomery County, where flooding of low-lying areas and small streams is possible.

6:30 p.m. update: No warnings are currently active across the immediate area, but there is still a chance for some severe weather as the line progresses east. The main risks for most spots should continue to be heavy rain and lightning. Additional storms out in front of the line are also producing plentiful rain and electricity.

Area radar as of 6:30 p.m. shows no active severe weather warnings in the immediate area at that time.

Recent lightning strikes are seen in pink, as of 6:10 p.m. (DC LMA)

6:12 p.m. update: The main line of storms to the west continues to press east. It is now along a Warrenton VA to Purcellville VA to near Frederick MD line. At this time only the northern section of the line is warned (through 6:30 as noted below). There is plenty of lightning and heavy rain associated with the rest though, and conditions may permit further severe storm warnings.

5:48 p.m. update: A severe thunderstorm warning is now up until 6:30 p.m. for northern Loudoun and southwestern Frederick counties as well as locations to the west. These storms may produce winds to 60 mph+. The trailing line is now pushing into western Loudoun County and south. It will progress through the western half of the area between now and about 8 p.m., probably reaching D.C. between about 7:30 and 8:30 assuming it holds together. Far western areas, now behind the line, have been removed from the tornado watch.

5:35 p.m. update: Video of the funnel cloud or tornado that was spotted near the Ft McHenry Tunnel in Baltimore has surfaced:

5:30 p.m. update: A severe thunderstorm warning has been issued for northern Loudoun County and surrounding areas to the west until 5:45 p.m. Winds to 60 mph or greater are possible. This is the same section that was tornado warned previously. Rotation has generally weakened but the risk may remain for a spinup as the area moves east and northeast.

Radar and velocity of tornado warning near Winchester at 5:11 p.m. Where reds and greens meet on the image at right is the area of interest. It has since weakened a bit and moved northeast.

5:18 p.m. update: A tornado was reported to have touched down near Fork, Md at 3:30 p.m. during the earlier broken line of storms that has since pushed east. The flash flood warning for D.C. and surrounds has been canceled. A line of storms approaching from the west is now nearing the Blue Ridge. It will begin to progress into the main part of the area over the coming period.

4:58 p.m. update: Line of storms along I-81 has triggered a TORNADO WARNING for NW Winchester into southern Berkeley County until 5:30 p.m. Possibly tornadic storm near Winchester, moving northeast at 20 mph.

Radar around 4:40 p.m. (RadarScope)

4:50 p.m. update: Right now, we see just mainly small pop-up thundershowers around the metro region. These are hit or miss, but may produce brief downpours. The main concern is an extended line of heavy showers and storms along I-81, which should reach the metro region between 7 and 10:00 p.m. from west to east. While a small, short-lived tornado is possible within this line, the main threats will be strong straight line winds and another round of heavy, possibly flooding, rain.

4:43 p.m. update: Another Baltimore funnel cloud photo, via FoxBaltimore:

4:30 p.m. update: Here’s a photo of a funnel cloud captured in Baltimore (presumably the same one referred to in our 4:15 p.m. update, which was seen at 3:44 p.m.), sent into the Baltimore Sun:

4:23 p.m. update: CWG’s Ian Livingston reports Reagan National has tallied 4.69 inches of rain this month – just 10 days in.  Normal rain for the entire month is 3.78 inches.

4:20 p.m. update: The National Weather Service reports two more flash flooding incidents in the last hour. At 4:11 p.m., Old Colchester road was reported to be closed due to flooding near the Occoquan.  At 3:41 p.m., Belle View Road was flooded in Alexandria.

4:15 p.m. update: So far, no confirmed tornadoes have touched down, but the National Weather Service reported there was funnel cloud siting in Baltimore.

3:55 p.m. update: Although the torrential rain with the last batch of storms has exited Alexandria, the National Weather Service reports rising water: CAMERON RUN IN ALEXANDRIA HAS JUMPED OVER FOUR FEET IN THE LAST HOUR. FLOODING IS POSSIBLE ALONG CAMERON RUN…WITH THE STREAM REACHING AT LEAST THE SAME LEVEL AS WHAT OCCURRED LAST FRIDAY.

More downpours may develop into the evening and the flash flood warning in Arlington, Alexandria and the District continues through 6 p.m., so exercise caution near creeks and streams.

3:40 p.m. update: Heavy storms are now along and/or east of I-95 from western Prince George’s county, through the east side of the District, and then up to around Baltimore.  The sun is coming out to the west, which may destabilize the atmosphere for a new round of storms this evening (timing 6-9 p.m. most likely).  We will continue to update you on evolving conditions.

3:25 p.m. update: TORNADO WARNING for central Harford County and eastern Baltimore County until 4 p.m.. Locations in possible path: Fallston, Pleasant Hills, Bel Air.  Take cover immediately.

3:15 p.m. update: Doppler estimated rainfall from the past hour shows the swath of torrential rain cutting through the District and downtown Baltimore.  Amounts have ranged from 0.75-1.25 inches – hence the flood warnings, especially given more on the way.  Another rain safety tip: if you’re using windshield wipers, turn on your headlights.

Doppler estimated rainfall 2:07-3:07 p.m. (Weather Underground)

3:00 p.m. update: Two pieces of advice regarding flash flooding: 1) Remember, never cross a flooded roadway in your car: turn around, don’t drown. 2) Keep children away from creeks and streams.

Right on cue, a flash flood warning is in effect for the District, Arlington County, the city of Alexandria and east central Fairfax County until 6 p.m.  And another flash flood warning covers southern Baltimore County and Baltimore City until 5:45 p.m.

2:40 p.m. update: A flash flood warning has been issued for southeast Prince William and southeast Fairfax counties until 5:30 p.m. One inch has fallen in this area and another 1 to 2 inches is possible in the coming hours.

2:37 p.m. update: Know the difference between a tornado watch and a warning. Remember: A tornado watch simply means conditions are favorable for tornadoes, not that tornadoes are inevitable. A warning, on the other hand, means a tornado has either been suggested by radar or has been confirmed on the ground, and that you should take action immediately.

2:34 p.m. update: Here’s a map of the area under the tornado watch. In addition to this watch covering much of Virginia, Maryland, and Delaware, another tornado watch covers areas of North and South Carolina until 10 p.m..

In terms of what to expect in our region, the NWS SPC says there’s a 60 percent chance of at least 2 tornadoes , and a 20 percent chance of a large tornado (EF2 or higher on the 0-5 Enhanced Fujita Scale). The odds of at least 10 severe wind events (58 mph or higher; or damage report consistent with 58 mph winds) are 80 percent. The probability of large hail is low – less than 10 percent.