11:35 p.m. update: Severe thunderstorm warnings have expired for the metro area but the line of storms, with some embedded downpours and gusty winds, continues affecting areas from around Arlington through the southern half of the District and then along and just south of Rt. 50 to near the Bay Bridge. The storms should push south through southern Maryland and across the Bay in the next hour. This will be the last update as the weather should quiet down for the rest of the night. Follow the Twitter feed above for any additional storm news this evening and scroll way down for the forecast through Wednesday.
11:20 p.m. update: Line of storms now stretches from near Fairfax to around Annapolis and continues to push southeast towards southern Maryland. The heaviest activity continues to be in Maryland. Doppler estimated winds suggest they’re mostly sub-severe, but a few strong gusts are still possible as this line continues racing through the region.
11:09 p.m. update: Heavy rain in southern Montgomery County is now pushing into northwest D.C. and will continue to push southeast. The outflow boundary with some strong wind gusts has swept south through Alexandria and the northern half of Prince George’s County and will move through southern Maryland over the next hour.
10:53 p.m. update: You may notice some of the strongest winds coming through a few minutes ahead of the rain. These winds are associated with an “outflow boundary” on the leading edge of the actual thunderstorm. Said front is pushing through Arlington/Alexandria and the District now.
10:41 p.m. update: A severe thunderstorm warning now covers most of the entire northern half of the D.C. area through 11:30 p.m. including the District and most/all of the Fairfax, Montgomery, Prince George’s and Anne Arundel counties. It also includes northern Charles County as the line of storms currently from eastern Loudoun County to around Baltimore swings east and southeast. The storms have a history of producing wind gusts which have damaged some trees to the north and west, but reports have been widely scattered as opposed to widespread. The storms should move through fairly quickly, with heavy rains and strong winds lasting just about 10-20 minutes.
10:35 p.m. update: Storms now stretch from just northwest of Baltimore to just southwest of Leesburg. The storms tend to be bit stronger in Maryland, and they’re pushing down the I-270 corridor towards the northern part of the beltway. They will move through pretty quickly with brief downpours, gusty winds, and the *possibility* of a damaging wind gust. Area south of Fairfax County will probably just get grazed by storms – they should not be particularly strong if they extend that far south.
10:25 p.m. update: Reports of tree damage have come with these storms as they’ve passed through Shepherdstown (W. Va.), Hagerstown, Frederick, and Westminster. They are now entering western Montgomery, Howard, and central Loudoun counties.
10:10 p.m. update: A severe thunderstorm warning has been extended south and covers Montgomery, eastern Loudoun, and northern Fairfax counties through 11 p.m. Line of storms is quickly advancing east and southeast. The area from roughly Reston to Damascus is likely to have a brief period of downpours and strong wind gusts, perhaps as high as 60+ mph.
Update, 10:00 p.m.: A thunderstorm WARNING has been issued for eastern Frederick, Howard, northern Anne Arundel, and areas to the northeast through Baltimore and into northeast Md. through 11 p.m. 60 mph or greater winds remain possible in the line which now extends from near Manchester, Md. to Charles Town, W.V.
Update, 9:45 p.m.: A Severe Thunderstorm Warning is up for southern Frederick and northern Loudoun counties until 10:15 p.m. for winds to 60 mph+. Frederick and Purcellville are among locations in the warning.
Update, 9:20 p.m.: Strong to severe thunderstorms are entering northern parts of the area. Frederick and Carroll counties are under a WARNING until 10 p.m. for winds to 60 mph or higher. The line is somewhat broken but appears ready to advance into the immediate area. Conditions remain quite supportive for nighttime storms thanks to high heat and humidity still lingering from today. If you are planning on being outside at any time in the next few hours, keep up with radar. The worst of the storms should pass fairly quickly.
Update, 8:50 p.m.: The Storm Prediction Center has placed the area under a Severe Thunderstorm Watch until 1 a.m. Storms approaching from the northwest may begin to enter into the area in the next few hours if they hold together. The line would reach D.C. between about 11 and midnight. The watch warns of winds as high as 70 mph in the worst of the storms.
Update, 8:25 p.m.: The line of storms to our north and northwest has prompted severe thunderstorm warnings to the Maryland/Pennsylvania border late this evening. The Storm Prediction Center is monitoring the northern half of the area in particular, including the D.C. area, for a new thunderstorm watch.
Update, 6:25 p.m.: A Severe Thunderstorm Watch has been issued for Frederick and Loudoun counties until 2 a.m. which have the greatest chance of being affected by the complex of storms currently in Pennsylvania, discussed below.
Today was hot, Wednesday may well be hotter. Reagan National Airport hit 94 today, the highest temperature since September 1, 2012 when it was 95. On Wednesday, we’ll have the opportunity to match or best that September reading, with fairly widespread mid-90s throughout the region. With all of the heat and humidity around, a thunderstorm or two is also in the mix.
Through Tonight: It’s a muggy night with lows most spots just 69-75 (suburbs-city). We need to watch a complex of storms forming in Pennsylvania that could (20-30 percent chance, highest odds northern suburbs) barge in here later tonight (10 p.m to 2 a.m.) but chances are storms remain to our north and northwest. If they make it here, heavy rain, loud thunder/frequent lightning, and strong winds are possible.
Tomorrow (Wednesday): Much like today, it’s very hot and humid. Highs reach the mid-90s with heat indices near 100 in the afternoon. Winds are generally light from the southwest at 5-10 mph. The chance for showers and storms is slightly higher than today, with about a one in three chance (35 percent). Any storms that form could be heavy, with downpours and gusty winds.