* Severe thunderstorm watch until 8 p.m. for entire region *
- Storms, some severe, are likely to pass through the Washington region through 8 p.m. Widely scattered storms are likely through 6 p.m. with more of a line of storms passing from west to east between about 6 and 8 p.m.
- In addition to heavy rain and lightning, some storms could contain hail and damaging wind gusts
5:55 p.m. – Strong to severe storms east of I-270 and exiting District, continuing to produce hail; More severe storms are coming in from the west
The first conglomeration of hail-producing storms is exiting I-270 corridor as well the District, and is entering Howard and Prince George’s County. But more intense storms follow on their heels from near Leesburg south to central Fauquier County and severe thunderstorm warnings are in effect for the possibility of wind gusts to 60 mph and perhaps some more hail.
5:40 p.m. – Some pictures of the hail hammering immediate D.C. area
5:25 p.m. – Most of immediate Washington area under severe thunderstorm warning, mainly due to hail
Pretty much the entire immediate metro region is under a severe thunderstorm warning for hail through 6 p.m.
The hail is mostly dime to quarter size, but is loud and will obviously hurt if it hits you so head inside.
Very heavy rain and pockets of very strong winds are also accompanying these storms.
5:20 p.m. – Severe thunderstorm warning Sterling, Reston, and Tysons until 6 p.m.; Warning also issued for Frederick and Damascus.
A severe storm over Sterling, with a history of producing hail, is moving at 30 mph toward Reston, Herndon, Oakton, Merrifield, and Tysons. It is also likely to produce heavy rain, lightning, and gusty winds.
To the north, a severe thunderstorm warning is in effect for the eastern half of Frederick County, including the city of Frederick, northern Montgomery County, and western Howard County until 6 p.m. Strong winds and hail are likely with this storm.
4:55 p.m. – Severe thunderstorm warning for Great Falls, Potomac and Bethesda until 5:30 p.m.; Second severe storm near Warrenton
A severe storm just west of Great Falls is moving southeast right along the Potomac River headed in the direction of Great Falls, Potomac and Bethesda over the next 30 to 45 minutes. This storm has a history of producing hail of up to a quarter size and could also unleash some strong winds. This storm has developed out ahead of the main area of storms to the west.
A second severe storm is located near Warrenton and could also produce hail and wind gusts up to 60 mph as it heads east toward western Prince William County (around Nokesville) over the next 30 to 45 minutes.
4:30 p.m. – Storms increasing our far western areas, and likely to affect immediate area starting around 6 p.m.
Storms have scattered in our far western areas, including Frederick, western Loudoun, western Fauquier, and western Montgomery counties, for the past couple of hours and have started to increase. They are also showing signs of making more of a move eastward toward the immediate area.
We expect storms to become numerous in our western suburbs by around 5:30 or 6 p.m. and inside the Beltway between 6 and 7 p.m. or so.
At the moment we have a warning for a storm (until 5 p.m.) affecting areas of northern Fauquier and southern Loudoun County for the possibility of winds to 60 mph and small hail:
Original article from 2 p.m.
A strong cold front crossing the region will drop high temperatures into the May-like low 70s on Monday. But, as it approaches and arrives this afternoon and evening, strong to severe thunderstorms are likely in the region.
A severe thunderstorm watch has been issued until 8 p.m. A watch means conditions are favorable for severe storms but is not a guarantee of hazardous weather. During a watch, you should remain weather-aware, have a way to receive storm warnings and be prepared to seek shelter, if necessary.
If a severe thunderstorm warning is issued for your location, it means severe storms are imminent and you should head indoors.
The main risk from storms moving through, in addition to heavy rain and lightning, will be damaging winds and hail. While unlikely, an isolated tornado cannot be ruled out, as well.
Storms should be most numerous between 5 and 8 p.m., but widely scattered storms could develop after 2 p.m. in our western areas and 3 p.m. elsewhere.
The approximate arrival time for the main line of storms (widely scattered storms possible before this, starting between 2 and 3 p.m.):
- 4 to 6 p.m. western areas.
- 5 to 7 p.m. immediate area, including the Capital Beltway.
- 5:30 to 7:30 p.m. areas east of Interstate 95.
All clear: after sunset.
Storm duration: 30 to 45 minutes or so.
Chance of measurable rainfall in any location: 60 percent.
Storm motion: west to east.
Likely storm effects: heavy rain, lightning, gusty winds.
Possible storm effects: damaging wind gusts, hail.
Very small chance of: large hail, brief tornado.
Rainfall potential: highly variable. Locally up to an inch or so in heaviest storms.
This afternoon and evening, a cold front approaches the region from the northwest, along with an energetic wave in the upper atmosphere. Both of these features will encourage warm, humid air to bubble upward and form thunderstorm clouds later today.
The Storm Prediction Center has placed our region in a slight risk zone for severe storms, level 2 out of 5 on its scale for the overall storm threat.
Showers and thunderstorms are already erupting over the high terrain to the west of the D.C. region. These should gradually coalesce into larger storm complexes that will then drift eastward toward the metro area.
The atmosphere is destabilizing, although some mid-level clouds may have slowed that process a bit. There is sufficient moisture in the lower atmosphere to support heavy convective showers and storms, but the atmosphere overall is drier than in the severe thunderstorm events of the past week.
Wind shear, the increase in wind speed with altitude, is also considerably weaker today than in the past week. This will limit the tendency for today’s storm to develop concentrated areas of rotation.
Even so, the combination of moderate instability and shear will be sufficient for thunderstorms that become better organized and stronger than “pop up” storms that fizzle after just 30 minutes or so.
More than one wave of storms may be generated. Widely scattered storms are possible mid- to late this afternoon before perhaps a more organized and widespread line or broken line of storms early this evening (between 5 and 8 p.m.).
Stay tuned for updates, which will be posted at the top of this article as needed.