A nasty looking line of thunderstorms approaching western Montgomery at this hour.

Two large cells to our west, one of which looks ready to pound Leesburg and Reston. The other one may very well hit McLean and DC.

Liiink: http://www.wunderground.com/stationmaps/gmap.asp?lat=38.94659&lon=-77.11578&zoom=9&type=hyb&rad=1&rad.num=6&rad.spd=25&rad.opa=70&rad.stm=0&wxsn=1&wxsn.mode=tw&svr=0&cams=0&sat=0

3:05pm -

Massive rain, wind and hail the size of dimes here in Leesburg at the moment. Be prepared as it comes on fast! Also, move your cars to a safe place.

Some severe reports coming in from Loudon County.. trees down in Philomont and .75" hail in Leesburg.

Looks somewhat like a bow echo--shades of June 4th!!! May need to exit the computer soon. I think we'll be seeing interesting weather here around the West Pike within an hour. It's probably near the west Beltway by now.

The echoes behind the leading edge of this storm are also quite abundant. We could be in for 3 to 6 hours of this weather. Fortunately I can stay home through it all.

This storm is throwing a wrench in Dulles airport's operations. Note the loop-shaped holding patterns that planes are flying right now. http://map11.flightaware.com/airport_map.rvt?ident=KIAD;key=088cfc537ffaa964bea863cd2bb9838e94cede0c;keytime=1213472418;height=600;width=800;keyv2=1cb80ffbb50171609ce83fb13b76c25af223f8c8

pretty gusty in Clarendon

Ian, why isnt NWS issuing a Severe T-Storm Watch? There are several Warnings up and down the DMV...damage and large hail in MoCo and LoCo already reported and more on the way...why would they NOT issue one - Im curious...Fathers Day weekend and they're understaffed?

A severe thunderstorm warning was issued for Montgomery County around 3pm.

Dulles ARC, This is somewhat of a marginal severe weather situation. There is very little wind shear today -- the storms are mostly fueled by a lot of instability (heat/humidity/sunshine). They are more or less "pulse" severe storms that are reacting to the heating of the day.. and because all the ingredients are not present, only a few of them are actually reaching severe levels. The Storm Prediction Center did actually updgrade the region into a "slight risk" for severe weather with their last update. They are staffed and watching the situation -- a new watch just went up in WI for storms there. The threat is simply too isolated in this area to put out a big watch box. We should see fewer severe warnings as we head towards sunset, and may have already peaked in that department.

The first round gave me (in NW Montgomery) about .40 inches with frequent cloud to ground lightning displays. Fire department in Mont Co responded to at least one structure struck by lightning. Second round is just now passing through the panhandle of WV.

Has anyone else noticed that nearly every storm system that passes through breaks up right over the city? Like there's some kind of force field?

Unbelievable. Here in Vienna, we had a solid line of heavy-to-severe intensity just to the west and it broke up just a couple miles west of town. One bad cell went north and a lesser one went south. All we got was a large outflow of 40 MPH winds or so from the northern cell, and almost no rain or lightning.

Didn't get much out of that last line in Georgetown, a little rain was about it. Looks like a pretty good supply to our SW, but I agree with Laura that lines often break up on approach to the District; heat island effect maybe? That's about all I can think of.

...And I also agree with CW team and think today's action doesn't warrants any watch boxes either, just summer in DC.

pardon my crappy grammar on that past post :)

Ian, I have to disagree. NWS should indeed have had a watch box out for the area. The threat was NOT isolated. We didn't get much right here in Vienna, but that was a NASTY cell to our N and W...reports of .75" to 1.0" hail. The cell to our south was only slightly less intense. And as I write this, another line seems to be forming in the Shenandoah Valley. That looks like the front itself. We'll have to see if it holds together long enough to hit the Metro Area.

I should also add that this was not an isolated severe threat because of the warm, humid, unstable air mass over us and the sharp cold front pushing in with significant uplifting. Those are two classic ingredients for strong-to-severe storms.

While NWS didn't completely blow it (they DID have us in a slight-risk area on the map) they clearly erred by not issuing a formal watch.

Ian,

Here in Arlington, it's been nothing but a little mist..Any strong/severe storms headed out this way?

Guys bookmark one of the several radar sites that are available or even look at the one that Capweather provides. It will tell you what you need to know.

Looks like a well-organized front is coming our way. This might be our chance for some substantial rainfall.

Thanks NTOMB...Unfortunately, I'm not a weather man and really do not know how to read the radar screens.

Rather, have the "experts" tell me what I need to know.

I agree with Dave. This event has "busted" in the West Pike/Columbia Heights West/Baileys Crossroads area. What appeared earlier to be a bow echo (near Dulles!) broke up into individual cells and the result here has been chiefly light rain with a few isolated wind gusts and occasional thunderclaps. There could be more action this evening as radar out closer to the front location in WV has been showing more echoes.

Right now I'm cloudy with little or no rain and an observed window temperature near 80.

Mike, so far there have only been 3 reports of severe weather in the LWX area -- all from the same cell embedded in the first line. On a day like today, with much less mid and upper level support for winds/rotation, it is harder to pinpoint exactly where the few storms will go severe.

I don't know the actual numbers of reports the NWS would want to consider a watch 'successful', but I would think it's more than a handful -- unless those 5 reports were massive tornadoes, but that's a different scenario.

Compared to bigger events we have had here this season, like June 4, today was lacking several important ingredients for widespread severe weather (the cold front actually lags behind these storms, and is not super cold -- tomorrow will be warm again).

High instability (like we saw today) leads to rapidly growing storms when they do form.. they are sometimes capable of producing a large hail report or two and a microburst with some wind damage. Overall, the most intense activity today was more on that isolated scale.

Second round about to enter western Montgomery County. Although it looks more sinister on radar I don't hear any thunder or see lightning like the first wave.

I'm pinning all my hopes for audio/visual entertainment from mother nature on this next line coming up through Pr. William now. After that I think we'll be done for the day.

Ian - I understand the rationale, but if we simply nowcast they should have issued the box. I've seen Watches that produced a lot less Warnings than today. To me, NWS needs to issue the watch for the normal, non-weather geeks. They dont care about instability at the upper levels. They just need to know if there is a chance that the wind may blow thier patio furniture around or that the hail may dent their car hood. That one storm probably affected almost a quarter million people. A Watch would have been appropriate given its definition by the NWS.

Rain was falling at a 45 degree angle in Bethesda while I was watching the second half of the Russia-Greece European Cup football match, round about 4 pm. The satellite feed went out for a few minutes at the bar, but I didn't miss any goals. And Greece lost :-(

A few branches, one of them maybe 20 feet long, were down on my way home in Chevy Chase.

Let me help you out Dave. Assuming that you can find your county on a map of the region look for precipitation on the radar map. Most sites have a feature where you can set the map in motion. Thunderstorms almost always move from west to east. Green colors signify lighter precipitation while yellow is moderate and red is heavy. A man named Dylan once said that you don't have to be a weatherman to tell you which way the wind blows.

Dave: Click here.
http://www.wunderground.com/stationmaps/gmap.asp?lat=38.94659&lon=-77.11578&zoom=9&type=hyb&rad=1&rad.num=6&rad.spd=25&rad.opa=70&rad.stm=0&wxsn=1&wxsn.mode=tw&svr=0&cams=0&sat=0

Anybody mention that CWG blew this forecast? Esp. the effects of the southern part of the area.

No storms in Silver Spring/ Hillandale area during the latest alert period.

How do you feel that CWG blew the forecast, Carol? I thought Jason got it dead on. I live to the south of the district, and there was very little here- just a few rumbles of thunder and some light rain.

How do you "blow" a thunderstorm forecast especially since lines of storms typically have gaps and dry slots? Did they "blow" the forecast last week when upper Montgomery County was nearly devestated while lower Montgomery got off easier?

Carol -- We certainly do get some forecasts wrong. But how exactly did we blow this one? We've been consistently calling for the possibility of storms today, often pinpointing them as afternoon or evening, since Monday. Objectively speaking, our forecasting for today during the past week turned out to be nearly spot-on.

I am here in Dumfries, VA for the weekend, and we got 2 pretty good storms. The first one was thunder and heavy rain. The second one we got was pretty big. Lots of thunder and lightning, rain so heavy you couldn't see the house across the street, and winds were really strong.

I got a video of it, so I'll upload it to youtube or something and post the link tomorrow or monday probably.

Weather bloggers, I present to you, the "Tin Yurl" as we call it at Nationals Journal, otherwise known as the tiny url. You look like you could use it.

http://tinyurl.com/

Carol-- I indicated everyone had a chance of storms (which was correct) and that the best chance of strong storms was to the north. It seems like the distribution of strong storms was spread out (rather than only in the north), so that part of the forecast was less than perfect, but a far cry from "blowing" it.

West Springfield (Lk Accotink/Mixing Bowl)--> Storm total as of 11:40pm tonight = 0.41"

The lightning storm from earlier in the week showered 0.17", but blew bark off of three trees (in strips) about 40 yards out from my house.

Pedestrian storms from my vantage point. I didn't experience anything more than TS2 conditions.

(For info on TS levels and my "Thunderscale" system, click here: http://tinyurl.com/522p99 )