An isolated thunderstorm produced wind damage over southeastern Fairfax County.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LWX wrote it up.
An isolated thunderstorm produced wind damage over southeastern Fairfax County.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Baltimore/Washington wrote its last area forecast discussion before the first event at Aug 22, 2:11 PM EST, 1 hour 34 minutes earlier.
Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 311 PM EDT Sun Aug 22 2021 .SYNOPSIS... An upper-level low will remain overhead today as Henri tracks into New England. The upper low will move off to our east tomorrow, allowing high pressure to build in for the first half of the week. A cold front will approach the area from the north toward the end of the week. && .NEAR TERM /THROUGH TONIGHT/... An upper level low remains situated overhead today. Meanwhile, Henri has tracked into southern New England. An area of stratiform rain is ongoing across northern and northeastern MD, while thunderstorms are starting to fire beneath the upper low across other portions of the forecast area. The area of stratiform rain over northeast MD is expected to continue to spread southeastward through the remainder of the afternoon into tonight. Most of MD and DC will see on and off showers through the night. This area of stratiform rain is having somewhat of a stabilizing influence, thereby inhibiting thunderstorm development in those areas. Elsewhere, storms may develop through the afternoon, with southern MD experiencing the greatest chance for storms. Current SPC mesoanalysis shows that the area of 1000+ J/kg MLCAPE is now confined to south of DC and east of the Blue Ridge. This will continue to be the area to watch through the remainder of the afternoon. Virtually no flow is present below 500 hPa and DCAPE values on the low side, so storms shouldn't be big wind producers. However, the same environmental characteristics will make it so storms are slow movers. As a result, an instance or two of flash flooding can't be ruled out where thunderstorms form. Locations near the bay/south of DC stand the greatest chance of seeing a heavy rain producing thunderstorm, as precipitable water values gradually increase from around 1.25 inches along the Allegheny Front to around 1.9 inches along the bay. As mentioned before, the threat for showers will linger through much of the overnight hours across the northeastern half of the forecast area. Further to the southwest, any thunderstorm activity will wind down shortly after dark. Some patchy fog may form toward daybreak across southwestern portions of the forecast area as winds go light and at least some clearing of cloud cover occurs. Locations that receive rainfall during the day will be most favored for fog formation overnight. Lows tonight will be in the mid 60s to lower 70s for most. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... The upper low that has been parked overhead all weekend will finally lift off to our north and east tomorrow. This will lead to height rises aloft. Despite northwesterly flow through a deep layer, a very warm and humid airmass will remain in place at the surface. Scattered thunderstorms are expected to develop tomorrow afternoon in response to daytime heating. While a storm can't be ruled out anywhere, locations to the east of the Blue Ridge will be most favored for the development of storms, since downslope west-northwesterly flow will have less of an influence compared to the Shenandoah Valley. Model soundings show that around 1000-1500 J/kg of MLCAPE is expected to develop by peak heating. Around 20-25 knots of northwesterly flow will be present through a deep layer, and with drier air moving in aloft, DCAPE values will also be higher than preceding days. These two factors will help to move storms along toward the south and east. As a result, there shouldn't be any threat for flash flooding, but stronger storms may produce gusty winds. Any thunderstorm activity should quickly wind down after dark. Heights will continue to rise aloft on Tuesday as high pressure builds in at the surface. This will result in quiet weather conditions across the area, with mostly sunny skies for all. Conditions will remain hot and humid, with highs in the lower to middle 90s and dewpoints in the upper 60s to lower 70s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... High pressure returns to the region for the bulk of the week, with hot and humid conditions and spotty afternoon thunderstorms. Forecast progression overall looks a little slower (about a day) than it did yesterday. Hottest and driest day of the long term looks likely to be Wednesday in the wake of Henri with best compressional heating as the system moves away and high pressure builds in. This wanes Thursday and Friday as high pressure, initially just to our west, shifts east and we start to get a stronger flow of moist tropical air back northward across the region. By Saturday into Sunday, we'll be watching a front approaching from the north, which may start to focus the storm development Saturday, then may stall in the area Sunday. Still lots of uncertainty with this, but overall looks like a stormier and cooling trend as we head into next weekend. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Prevailing VFR conditions are expected through Tuesday. VCTS mentions have been removed from the terminals this afternoon, as an area of stratiform precipitation across northeastern MD will provide a stabilizing influence. There's still a very small chance that a thunderstorm could pop up near DCA in the next hour or so before that stabilizing influence reaches the terminal. On and off showers are expected through the night at DCA, BWI, MTN and IAD. A stray shower or brief thunderstorm can't be ruled out at MRB or CHO late this afternoon into this evening. Thunderstorms may be possible again tomorrow afternoon, with DCA, BWI and MTN having the greatest chance for a passing storm. Dry conditions are expected at the terminals on Tuesday. Winds will be light today into tonight, before picking up out of the west tomorrow. Winds may gust to around 15 knots tomorrow afternoon. Lighter northwesterly winds are in the forecast for Tuesday. Generally VFR Wednesday through Friday under high pressure. Main concern is for patchy early morning fog and isolated to scattered afternoon/early evening thunderstorms. Best risk of both will be at MRB and CHO. The risk likely is lowest on Wednesday with a gradual increase in chances through Friday. && .MARINE... Sub-SCA level winds are expected through Tuesday. Prevailing winds will be light out of the north today into tonight, before turning out of the west tomorrow. Winds may gust to around 15 knots in westerly flow tomorrow, but aren't expected to reach SCA criteria. Lighter northwesterly flow is expected on Tuesday. SMWs may be needed for locally higher winds in thunderstorms both this afternoon and tomorrow afternoon. No thunderstorms are forecast over the waters on Tuesday. Light winds likely prevail over Wednesday thru Friday under high pressure. Only concern would be for an isolated thunderstorm reaching the waters. The risk likely is lowest on Wednesday with a gradual increase in chances through Friday. && .TIDES/COASTAL FLOODING... Latest guidance has continued to keep tidal anomalies lower. Most sites with the exception of DC Waterfront and Annapolis will remain below action stage over the next few days. Otherwise, not anticipating any minor tidal flooding issues over the next few days. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && SYNOPSIS...KJP NEAR TERM...KJP SHORT TERM...KJP LONG TERM...RCM AVIATION...RCM/KJP MARINE...RCM/KJP TIDES/COASTAL FLOODING...LWX
Hazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 445 PM EDT Sun Aug 22 2021 ANZ530>543-DCZ001-MDZ008-011-013-014-016>018-504-506-508- VAZ052>057-232045- Chesapeake Bay north of Pooles Island MD- Chesapeake Bay from Pooles Island to Sandy Point MD- Chesapeake Bay from Sandy Point to North Beach MD- Chesapeake Bay from North Beach to Drum Point MD- Chesapeake Bay from Drum Point MD to Smith Point VA- Tidal Potomac from Key Bridge to Indian Head MD- Tidal Potomac from Indian Head to Cobb Island MD- Tidal Potomac from Cobb Island MD to Smith Point VA- Patapsco River including Baltimore Harbor- Chester River to Queenstown MD-Eastern Bay- Choptank River to Cambridge MD and the Little Choptank River- Patuxent River to Broomes Island MD- Tangier Sound and the inland waters surrounding Bloodsworth Island-District of Columbia-Cecil-Southern Baltimore- Prince Georges-Anne Arundel-Charles-St. Marys-Calvert- Central and Southeast Montgomery-Central and Southeast Howard- Southeast Harford-Prince William/Manassas/Manassas Park-Fairfax- Arlington/Falls Church/Alexandria-Stafford-Spotsylvania- King George- 445 PM EDT Sun Aug 22 2021 This Hazardous Weather Outlook is for the Maryland portion of the Chesapeake Bay, Tidal Potomac River, and I-95 corridor through central Maryland, northern Virginia, and District of Columbia. .DAY ONE...Tonight Isolated instances of flash flooding are possible today and tonight in association with Henri, particularly near and northeast of Baltimore. An isolated severe thunderstorm is possible this afternoon into the evening. Large hail and damaging winds are possible in the strongest storms. .DAYS TWO THROUGH SEVEN...Monday through Saturday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be necessary today. MDZ003>006-503-505-507-VAZ025>031-036>040-050-051-501-502-505>508- WVZ050>053-055-232045- Washington-Frederick MD-Carroll-Northern Baltimore- Northwest Montgomery-Northwest Howard-Northwest Harford-Augusta- Rockingham-Shenandoah-Frederick VA-Page-Warren-Clarke-Nelson- Albemarle-Greene-Madison-Rappahannock-Orange-Culpeper- Northern Fauquier-Southern Fauquier-Western Loudoun- Eastern Loudoun-Northern Virginia Blue Ridge- Central Virginia Blue Ridge-Hampshire-Morgan-Berkeley-Jefferson- Hardy- 445 PM EDT Sun Aug 22 2021 This Hazardous Weather Outlook is for portions of eastern West Virginia, northern and central Virginia, and central and western Maryland. .DAY ONE...Tonight Isolated instances of flash flooding are possible today and tonight in association with Henri, particularly near and northeast of Baltimore. .DAYS TWO THROUGH SEVEN...Monday through Saturday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be necessary today. MDZ001-501-502-VAZ503-504-WVZ501>506-232045- Garrett-Extreme Western Allegany-Central and Eastern Allegany- Western Highland-Eastern Highland-Western Grant-Eastern Grant- Western Mineral-Eastern Mineral-Western Pendleton- Eastern Pendleton- 445 PM EDT Sun Aug 22 2021 This Hazardous Weather Outlook is for the Allegheny Front counties in western Maryland, eastern West Virginia, and Highland County Virginia. .DAY ONE...Tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Monday through Saturday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation not expected at this time. CJL
The Sterling radar (KLWX), 39 km away, was scanning. The volume nearest the first event began at 20:44 UTC.
3 thunderstorm wind. Local standard time, as filed.
Wires blew down near the intersection of VA-611 Old Colchester Road and Stewart Road.
A tree blew down on the Pohick Bay Golf Course.
Seven trees blew down in Mason Neck State Park. Three to four inch in diameter tree limbs blew down along Harley Road next to the park.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Virginia in 2021Every state in 2021This day in weather historyWarnings in Virginia, August 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 967737, 967738, 967739.