* Severe thunderstorm watch until 8 p.m. for entire region *

Key points

  • Storms late Sunday afternoon and evening produced widespread reports of hail — mostly marble-size, but some up to golf ball-size. Pockets of damaging winds also were observed from around Great Falls through Bethesda and Rockville.
  • Much cooler and drier air spills into the Washington region Sunday. Monday morning lows dip into the 50s with highs only in the low 70s Monday afternoon.

7:30 p.m. - Hail falls in evening. Weather will be delightfully cooler Monday.

The last of the storms are pushing through southern Maryland. All watches and warnings should expire at 8 p.m.

The hailstorm that pushed through parts of Fairfax and Montgomery County and parts of the District was one to remember. Here are a few more impressive images:

Now we can look ahead to a couple of days of sunny, cooler-than-normal weather. Here’s the forecast:

Tonight: Becoming mostly clear and much cooler overnight with lows in the mid- to upper 50s under a northwest wind about 10 mph.

Monday: Mostly sunny with a much more comfortable air mass in place. Highs will top out in the low 70s and winds from the northwest will be gusty (more than 20 mph) at times. Clear and quite cool tomorrow night with lows in the upper 40s to low 50s.

This will be our last update of the evening.

7:15 p.m. - Storms exiting, rainbows in their wake

6:55 p.m. - Storms crossing Interstate 95. Heaviest activity in Southern Maryland now.

The worst of the storms is over for much of the region and we see the concluding line along and east of Interstate 95, pushing eastward. For the most part, these storms are no longer hail producers and just putting out heavy rain and some lightning.

The most intense storms are passing through Southern Maryland, where storm warnings stretch from Waldorf and St. Charles to the Bay. These storms may still produce some high winds and hail as they press east.

West of the Beltway, you’re just about in the clear.

6:30 p.m. - Interstate 270 corridor getting battered by big storms

A new warning is out for severe storms from Germantown to Gaithersburg east to around Olney through 7 p.m. An intense area of storms in this zone may produce damaging wind gusts and hail.

Storms extend to the south along the west branch of the Beltway and then just west of Interstate 95 through Burke and Dale City. These storms are generally not severe but still contain heavy rain and lightning and still have to cross the Beltway.

6:15 p.m. - Storms all over the Washington region, most intense in Dale City and approaching Columbia

After the burst of hail in many areas as the initial onslaught of storms came through, the intensity of storms has, in general, lessened a bit. But we still have severe thunderstorm warnings sprayed all over the region for the possibility of hail and wind gusts to 60 mph.

The most intense storms at the moment are exiting Dale City, Va., headed right over Interstate 95 and approaching Columbia, Md., also about to pass over Interstate 95. These storms are along the front line of activity that produced hail in the District and many locations to the west.

A second line of storms from Gaithersburg south through western Prince William County and southern Fauquier County in Virginia. These are not as intense but still have to pass through the immediate area over the next hour or so.

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 the I-270 corridor as well the District and entering Howard, Md., 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 up 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 it is loud and will obviously hurt if it hits you, so head inside.

Very heavy rain and pockets of very strong winds also are accompanying these storms.

5:20 p.m. - Severe thunderstorm warning for 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 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 probable 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 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 in far western areas and could 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 predicted in the region.

A severe thunderstorm watch has been issued until 8 p.m. A watch means conditions are favorable for severe storms, but it 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. Though unlikely, an isolated tornado cannot be ruled out.

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.

Storm dashboard


x (The Washington Post/The Washington Post)

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. in western areas.
  • 5 to 7 p.m. in immediate area, including the Capital Beltway.
  • 5:30 to 7:30 p.m. in 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.

Discussion

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.


Risk level for severe storms on Sunday from National Weather Service.

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.).


HRRR model radar simulation of storms between 5 and 8 p.m.

Stay tuned for updates, which will be posted at the top of this article as needed.