Scattered thunderstorms produced several instances of localized wind damage.
Every event with a place to put it. Tap one for its entry below.
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.
Scattered thunderstorms produced several instances of localized wind damage.
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 25, 8:36 PM EST, 19 minutes earlier.
Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 936 PM EDT Wed Aug 25 2021 .SYNOPSIS... High pressure will remain situated near our region through the end of the week. A front will drop down into the region from the Great Lakes late Friday into Saturday and stall nearby through early next week. Another front may impact our region midway through next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Most convection has weakened into remnant showers this evening. One exception is over western Maryland where outflow from early storms in the Ohio Valley is intersecting an environment that hasn't seen storms already. Would expect this activity to gradually weaken as well as boundary layer stabilization continues to increase. Convective debris clouds should clear out enough later tonight to allow some patchy fog to develop, especially in the valley locations that have seen rain. Locally dense fog is possible. Otherwise mild and muggy conditions will continue with lows ranging from the mid 60s to mid 70s. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... A surface trough will remain situated over our region on Thursday with broad ridging to the north and a Bermuda high to the south of our region. The position of the trough seems to be more southwest to northeast on Thursday which become the focus for shower and thunderstorms to form. Dewpoints will increase tomorrow due to continued warm air advection from the high pressure to the south of our region. Dewpoints increasing into the low to mid 70s will allow CAPE to increase above 2000 once again with a continued light mean flow. Showers and thunderstorms will again be a threat during the afternoon period with the main focus west of the Blue Ridge. Storms will initially form off of the terrain and then feed off of the generous amounts of CAPE in place over our region. Shear will be lacking but pulse strong to severe thunderstorms will be possible once again with damaging winds and isolated flooding being the main hazards. Afternoon temperatures will have similar highs in the low to mid 90s but higher dewpoints may lead to heat indices reaching potentially up to 100/105 threshold which may require a heat advisory for portions of our region on Thursday. Overnight lows will continue to be in the mid 70s Thursday evening. The best chance for widespread thunderstorms over the next three days will likely occur on Friday as an approaching front becomes the focus for the development of showers and thunderstorms. There remains some uncertainty on the timing of the frontal passage and threat could be pushed to the weekend if the front moves through slower. Ahead of the boundary, continuing warm air advection will lead to dewpoint temps peaking in the low to mid 70s during the afternoon with high temps in the mid 90s. Heat Indices may approach the 105 degree mark once again on Friday but confidence is much lower on this threat. The rising dewpoints will lead to another day of 2000 + CAPE with relatively weak shear. Pulse storms possibly driven by the approaching front could become strong to severe and produce some locally damaging winds. At this time, the main threat area seems to be north and west of the I-95 corridor. If the front moves into our region earlier, the threat for widespread thunderstorms will increase while a slower trend will mean less coverage of storms. The pulse nature of the storms along with a slow mean layer wind flow mean that isolated flooding could also be a threat if a storm remains over the same area for an extended period. The threat for showers and thunderstorms should diminish after daybreak with only a slight chance for showers overnight and into Saturday morning. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... A weak boundary across the region and a series of low pressure systems will bring the chance for showers and isolated severe thunderstorms each day Saturday through Monday. These severe thunderstorms could also lead to isolated instances of flash flooding considering the humidity and warmth during each day. Temperatures will top out near 90 each afternoon. The aforementioned boundary will get some upper level cool air assistance and should push farther south over our southern zones or perhaps as far south as the Virginia and North Carolina border Monday night. The threat for isolated severe thunderstorms and isolated flash flooding will linger and could become more widespread during the late afternoon and early evening hours on Tuesday. High temperatures will reach the middle 80s. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... VFR conditions generally expected through Friday with winds generally out of the south. Some showers and convective debris remain in the region this evening, but radar trends suggest significant impacts to ceilings or visibility remain unlikely. Late tonight, patchy fog is possible. Included BR at MRB at CHO since both had rain in the vicinity today along with climatology. While IAD also saw heavy rain, fog formation is less certain...perhaps shallow ground fog. Terminals near and west of the Blue Ridge Mtns (MRB,CHO,IAD) will have the best chance of experiencing periods of showers and thunderstorms once again Thursday and Friday. For now, have included VCTS at CHO/MRB in the TAF for Thursday afternoon given some consistency in model guidance. These showers and storms will have the potential to produce brief restrictions down into the MVFR/IFR range. Strong winds gusts of 20 to 30 knots will be possible within thunderstorms, potentially higher with a direct impact. Afternoon Temperatures over the tarmac will be in the mid 90s with heat indices above 100 possible. For the extended forecast, showers and thunderstorms will continue to be possible each afternoon and evening. Otherwise, VFR conditions expected at the terminals. The terminals that receive a good dose of rainfall could encounter some fog at night that could in turn drop visibility to IFR. Winds light and variable Saturday through Sunday morning, except for higher gusts in strong to severe thunderstorms. Winds becoming southeast 5 to 10 knots Sunday afternoon and night. && .MARINE... High pressure will remain situated near our region through the end of the week. A front will slowly approach our waters late Friday and into this weekend. No SCA level winds are expected but a few gusty thunderstorms are possible each afternoon and evening, with the highest chance near DC/Baltimore. No marine hazards expected Saturday through Sunday night. Any strong thunderstorms that develop and move over the waters could prompt a Special Marine Warning or two Saturday through Sunday evening. Winds variable Saturday through Sunday midday, then southeast around 10 knots Sunday afternoon and evening. && .TIDES/COASTAL FLOODING... Tide levels are forecast to remain slightly elevated over the next several days. Although flooding is not explicitly forecast, caution (or near minor) stages are possible at more vulnerable tidal locations such as DC SW Waterfront and Annapolis through the end of the week. && .EQUIPMENT... There was no KIAD upper air observation this evening due to lightning throughout the entire launch window. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && SYNOPSIS...JMG NEAR TERM...ADS SHORT TERM...JMG LONG TERM...KLW AVIATION...ADS/KLW/JMG MARINE...ADS/KLW/JMG TIDES/COASTAL FLOODING...LWX
Hazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 402 PM EDT Wed Aug 25 2021 ANZ530>543-DCZ001-MDZ008-011-013-014-016>018-504-506-508- VAZ052>057-261000- 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- 402 PM EDT Wed Aug 25 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 A severe thunderstorm capable of producing damaging wind gusts is possible this afternoon and evening, especially near and west of Interstate 95. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Isolated severe thunderstorms or instances of flash flooding are possible during the afternoon and evening hours each day. Heat indices up to 105 degrees are possible Thursday afternoon. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed later this week. MDZ003>006-503-505-507-VAZ025>031-036>040-050-051-501-502-505>508- WVZ050>053-055-261000- 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- 402 PM EDT Wed Aug 25 2021 This Hazardous Weather Outlook is for portions of eastern West Virginia, northern and central Virginia, and central and western Maryland. .DAY ONE...Tonight A few severe storms capable of producing damaging wind gusts are possible this afternoon and evening. Isolated instances of flash flooding are possible as well. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Isolated severe thunderstorms or instances of flash flooding are possible during the afternoon and evening hours each day. Heat indices may approach 100 degrees Thursday afternoon. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon, and again later this week. MDZ001-501-502-VAZ503-504-WVZ501>506-261000- Garrett-Extreme Western Allegany-Central and Eastern Allegany- Western Highland-Eastern Highland-Western Grant-Eastern Grant- Western Mineral-Eastern Mineral-Western Pendleton- Eastern Pendleton- 402 PM EDT Wed Aug 25 2021 This Hazardous Weather Outlook is for the Allegheny Front counties in western Maryland, eastern West Virginia, and Highland County Virginia. .DAY ONE...Tonight A few severe storms capable of producing damaging wind gusts are possible this afternoon and evening. Isolated instances of flash flooding are possible as well. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Isolated severe thunderstorms or instances of flash flooding are possible during the afternoon and evening hours each day. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed later this week.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
847 PM EDT WED AUG 25 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0555 PM TSTM WND DMG 1 ENE BROADWAY 38.62N 78.78W
08/25/2021 ROCKINGHAM VA 911 CALL CENTER
TREES DOWN NEAR BROADWAY, INCLUDING NEAR THE
INTERSECTION OF VA-801 HOLSINGER ROAD AND DOVE LANE.
&&
EVENT NUMBER LWX2105598
DHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
848 PM EDT WED AUG 25 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0840 PM FLOOD 3 NE LINVILLE 38.55N 78.79W
08/25/2021 ROCKINGHAM VA 911 CALL CENTER
VA-619 PHILLIPS STORE ROAD PARTIALLY BLOCKED BY HIGH
WATER NEAR VA-806 LACEY SPRING ROAD.
&&
EVENT NUMBER LWX2105599
DHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
855 PM EDT WED AUG 25 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0555 PM TSTM WND DMG 4 NNE VERONA 38.26N 78.98W
08/25/2021 AUGUSTA VA 911 CALL CENTER
SEVERAL TREES AND WIRES DOWN NEAR MOUNT SIDNEY.
&&
EVENT NUMBER LWX2105600
DHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
856 PM EDT WED AUG 25 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0540 PM TSTM WND DMG 2 N MOSCOW 38.34N 79.09W
08/25/2021 AUGUSTA VA 911 CALL CENTER
SEVERAL TREES AND WIRES DOWN IN THE MOUNT SOLON AREA.
&&
EVENT NUMBER LWX2105601
DHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
858 PM EDT WED AUG 25 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0615 PM TSTM WND DMG 1 N GREENVILLE 38.02N 79.15W
08/25/2021 AUGUSTA VA 911 CALL CENTER
TREE DOWN IN THE RIVERHEADS AREA.
&&
EVENT NUMBER LWX2105602
DHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
955 PM EDT WED AUG 25 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0603 PM TSTM WND DMG 1 ESE LEAKSVILLE 38.62N 78.50W
08/25/2021 PAGE VA EMERGENCY MNGR
TREE DOWN ON MILLS CREEK CROSSROADS NEAR THE
INTERSECTION OF RTE 638
&&
EVENT NUMBER LWX2105603
ADMThe Sterling radar (KLWX), 113 km away, was scanning. The volume nearest the first event began at 01:56 UTC.
1 thunderstorm wind. Local standard time, as filed.
Trees blew down near the intersection of National Pike Northeast and Mountain Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maryland in 2021Every state in 2021This day in weather historyWarnings in Maryland, 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: 969195.