The Washington PostDemocracy Dies in Darkness

Storms leave behind scattered damage, 20,000 outages

Flood warnings are in effect overnight due to high water near area streams as cooler air arrives

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Radar courtesy MyRadar | © OpenStreetMap contributors

* Flood warning for northern Fairfax County, the District and Montgomery County until around 2 a.m. *

9:00 p.m. — Severe storms depart with cooler weather incoming, but rain and flood risk linger

Our turbulent bout of weather is coming to a close. Today’s heat (Dulles set a record high of 91) and humidity energized two lines of severe storms. The first line concentrated from the Beltway northward, producing a 59 mph gust at Reagan National Airport. The second line swept through much of the area, unleashing a 59 mph gust at Dulles Airport. In the wake of the second line, PowerOutage.US reports about 20,000 customers without electricity in northern Virginia.

Both lines of storms were responsible for scattered downed trees across the region, while the first line produced small hail from Vienna through South Arlington.

Radar shows heavy storms from the second line have departed all but southern Maryland. However, moderate rain in their wake — combined with downpours from earlier — have raised the levels of area waterways, prompting flooding warnings in parts of Fairfax County, Montgomery County and the District. Avoid driving near streams that flood tonight and remember never cross a flooded road in your vehicle: Turn around, don’t drown.

The rain should end over the next couple of hours but high water may linger into the predawn hours. It remains mostly cloudy overnight with much cooler conditions. Low temperatures will range from 58-62 degrees with a north wind at 10-15 mph.

On Monday, cloud cover will be hard to break in the first part of the day, with some breaks of sunshine possible in the afternoon. Much cooler temperatures with highs in the low 70s and a light north wind. Just a slight chance at a stray shower in the afternoon. Shower chances increase overnight tomorrow with continued cool temperatures. Lows will range from 55-59 degrees.

7:50 p.m. — Storm warning extended into areas east of I-95

The second line of storms is now approaching I-95 north of the Beltway and has already crossed it to the south. The line is producing very heavy rain and lightning, with the strongest winds generally south of downtown Washington. A severe thunderstorm warning covers all of our eastern suburbs through 8:30 p.m. The areas most at risk of damaging wind gusts are along and south of Rt. 50.

7:40 p.m. — Menacing shelf cloud fronts severe storms

The line of severe storms, which stretches from near Damascus in Montgomery County south to around Fredericksburg, is entering the District now. It recently unleashed a gust of 68 mph near Centreville. Here are some scenes of what the storms look like on approach:

7:10 p.m. — Severe thunderstorm warning for much of area as second line moves in

This second line of storm has picked up some steam in our western areas prompting a severe thunderstorm warning for pretty much the entire area along and west of Interstate 95 until 8 p.m. Winds gusted up to 58 mph as the storm hit Dulles Airport and bursts of damaging winds are possible in the warning area. However, we do think the storms may weaken some as they get closer to the metro area due to the earlier storms (which used up some of the available energy).

6:30 p.m. — New line of storms approaching western areas — to pass through area next couple hours

While the southernmost cell along the initial line of storms is still packing a punch in Prince George’s County, we’re also watching a second line coming in from the west.

This second line stretch from northern Loudoun County to east of Charlottesville but there are no severe storm warnings associated with it in Northern Virginia. It may have difficulty gaining too much intensity when it reaches the D.C. area because the earlier storms used up a lot of the available energy.

Still, this second line could produce some downpours as it passes through the area from west to east over the next couple of hours. These storms may be a bit more intense in our southern areas which were not hit by the initial line while entirely missing or just skirting areas north of Montgomery County.

6:05 p.m. — Storms from northern Anne Arundel County to Arlington pushing east, producing hail in some areas

The line of storms has mainly pushed east of I-95, with storms extending from near Glen Burnie in Anne Arundel County to south Arlington. The storms are most intense on the line’s southern flank where they have produced hail as they’ve tracked through Vienna, Falls Church and Arlington. The storm also unleashed a 59 mph wind gust at Reagan National Airport and we’ve seen some scattered reports of downed trees.

A new severe thunderstorm warning is in effect for the southern part of the line stretching from south Arlington through Alexandria and downtown Washington into southwest Prince George’s County, where the storm could continue to produce hail in addition to strong wind gusts, downpours and lightning.

We’re also tracking a trailing line of storms that has just crossed Interstate 81 and stretches from just east of Winchester through Charlottesville. This line could produce some scattered severe storms in our southern suburbs between about 7 and 9 p.m. Areas from the Beltway north, however, will have probably seen their worst weather from the initial line.

5:35 p.m. — Scenes of the storms

Radar shows the various storm cells have consolidated into a solid line from Baltimore to Silver Spring to northwest Washington to Arlington to Falls Church — very close to paralleling Interstate 95. The storms — pushing eastward — are producing heavy downpours, a few strong wind gusts, lightning and a bit of hail. Here are some scenes from social media:

5:12 p.m. — Severe thunderstorm warning for eastern Fairfax County, southern Montgomery County and northwest Washington until 6 p.m.

As noted in the 5:10 p.m. update below, the storm in northern Fairfax County has expanded and intensified prompting a severe thunderstorm warning for areas to the east and southeast. This storm will produce very heavy rain, strong winds, lightning and some hail as it pushes east and southeast inside the Beltway.

We’ve received multiple reports of small hail from Vienna as this storm has blossomed. Head inside if you’re under this warning!

5:10 p.m. — Storm has expanded south and will move inside Beltway area next hour

While heavy storms drench northeast Montgomery and Howard counties, a storm cell has expanded over northern Fairfax County and is poised to head inside the Beltway; locations including McLean, Arlington, Bethesda, northwest Washington and Silver Spring should expect some downpours and lightning over the next hour. Areas south of I-66 and Rt. 50 may just get grazed unless the storm is able to expand farther south.

4:50 p.m. — Heavy storms in northern Montgomery County heading toward Howard County

Much of northern Montgomery County is under a severe thunderstorm warning as a cell with very heavy rain, gusty winds, frequent lightning and perhaps some small hail passes by. It will push through much of Howard County over the next hour.

A severe thunderstorm warning has been issued for much of Howard, southern Baltimore and northern Anne Arundel counties until 5:30 p.m. This includes the city of Baltimore.

Some weaker cells trail to the southwest near the Fairfax and Loudoun county line between Sterling and Oakton are not particularly intense at the moment but could develop as they push east through northern Fairfax County through around 5:30 p.m.

We’re also tracking a line of showers and storms to the west pushing toward the Interstate 81 corridor that could affect much of the region around sunset.

4:25 p.m. — Severe storms in Loudoun County and near Frederick-Montgomery county line pushing east-northeast

Radar shows two areas of intense storms — north and northwest of the Beltway, which have prompted warnings:

  • A multicell storm east of Frederick is bringing heavy downpours, gusty winds and lightning from around Mt. Airy to Clarksburg. It’s aimed at Damascus and western Howard County over the next 30 minutes or so. This storm has a history of producing small hail.
  • A storm near Ashburn is pushing east-northwest toward Sterling and southwest Montgomery County. It could reach the I-270 corridor near Rockville by around 5 p.m.

Although these storms may appear to be headed north of the Beltway, they may become joined and expand to the south over the next 40 minutes. We will monitor them. If these storms miss, a more solid line developing along the front in West Virginia will pass through much of the area closer to sunset.

2:15 p.m. — Severe thunderstorm watch issued until 9 p.m.

As a strong cold front meets hot, humid air over the region, thunderstorms are expected to erupt late this afternoon and early this evening. The National Weather Service has issued a severe thunderstorm watch over a large area affecting more than 22 million people that extends from central Virginia to central New York, including the Washington-Baltimore region, until 9 p.m.

Storms are most probable between about 4 and 8 p.m., arriving first in our western areas. In the immediate area (inside the Beltway), model simulations suggest they will arrive around 5 or 6 p.m. although small shifts in this timing are possible.

“Today’s setup features a slowly approaching cold front and an unstable airmass,” wrote Jeff Halverson, Capital Weather Gang’s severe weather expert. “One to two rounds of storms are expected to fire this afternoon into evening. Storms will generally be short-lived but locally intense, with scattered instances of wind damage, torrential rain and significant lightning. The first batch will move off the mountains mid-afternoon with a possible second batch along the cold front this evening.”

Remember that a severe thunderstorm watch means conditions are favorable for severe storms, not a guarantee. However, if a severe thunderstorm warning is issued for your location, it means a severe storm is imminent and you should seek shelter immediately.

Stay weather-aware if you are outside into this evening, and head indoors if thunder roars.

We will post additional updates as storms develop and move into the area.

Original forecast from 6 a.m.

Today’s daily digit

A somewhat subjective rating of the day’s weather, on a scale of 0 to 10.

3/10: The air remains hot, humid and stagnant. Late-day storms are poised to sweep the heat and humidity away, but they could be strong to severe as they cut outdoor plans short.

Express forecast

  • Today: Hot and humid, p.m. showers and storms. Highs: Near 90 to low 90s.
  • Tonight: Lingering evening showers and storms. Lows: Low to mid-60s.
  • Tomorrow: Turning partly sunny, cooler, passing p.m. shower? Highs: Low 70s.

Forecast in detail

It’s still unseasonably hot and humid, despite increasing midafternoon clouds, with a heat index reaching the mid-90s making it uncomfortable to be outdoors for too long. A cold front probably triggers a round of storms late this afternoon into evening, followed by much cooler air Monday through Wednesday with some clouds and a few showers.

Today (Sunday): Skies are partly to mostly sunny, with maybe a spotty morning shower or sprinkle, as temperatures once again head for well above average, with afternoon highs near 90 to the low 90s and plenty of humidity (dew points in the mid- to upper 60s). Clouds increase by midafternoon as a cold front approaches, with a line of storms likely moving through from west to east around 4 to 9 p.m. A few storms could be severe with damaging winds, heavy rain and lightning. Confidence: Medium-High

Tonight: The strongest showers and storms should depart to the east by 9 p.m. or so, but a lingering weaker shower or thundershower remains possible through around midnight. Otherwise, cloudy skies remain as a breeze from the north brings in cooler and drier air with lows in the low to mid-60s. Confidence: Medium-High

Follow us on Facebook, Twitter, and Instagram for the latest weather updates. Keep reading for the forecast through the weekend …

Tomorrow (Monday): The cloud cover might be slow to leave, but we should end up partly sunny. We’re noticeably cooler with highs in the low 70s — much more seasonable for this time of year — and can’t rule out a passing afternoon shower. A bit of a breeze out of the north adds a refreshing coolness to the air, and it should feel a little easier to breathe thanks to the lower humidity (dew points near 50). Confidence: Medium-High

Tomorrow night: If you can manage the pollen levels, it’s a good night to open the windows, even with the chance of a few showers. Cooler lows in the mid-50s to near 60 make for a more tranquil night for restful sleep. Confidence: Medium

A look ahead

A stalled front lingers to our south Tuesday and Wednesday. That means partly to mostly cloudy skies and the chance of a few showers each day, though by no means a washout as of now, with daytime highs near 70 to the mid-70s. Confidence: Medium

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