Alert archive / Maryland / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 464, NWS Baltimore/Washington

August 27, 2021Carroll County, Frederick County, Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at Aug 27, 2021, 4:14 PM EDT for Carroll County, Frederick County, Maryland. It was in force for 46 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 27, 2021, 4:14 PM EDT (20:14 UTC)
Expired
Aug 27, 2021, 5:00 PM EDT
In force
46 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Carroll County, MD, Frederick County, MD

The radar

The Sterling radar (KLWX), 83 km from the middle of the area, began a volume at 20:17 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Aug 27, 4:14 PM EDTTSTM WND DMG1 Ese Emmitsburg, MDTREES BLEW DOWN ON US-15 NEAR EMMITSBURG.
Aug 27, 4:17 PM EDTTSTM WND DMG1 Ese Emmitsburg, MDTREE DOWN ON US-15

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 2 storm reports to this severe thunderstorm warning; the first came 0 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.2 hours before the alert went out and 82 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2021-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 780 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2021-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
780 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
983 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
41 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

271 
WUUS51 KLWX 272014
SVRLWX
MDC013-021-272100-
/O.NEW.KLWX.SV.W.0464.210827T2014Z-210827T2100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Baltimore MD/Washington DC
414 PM EDT Fri Aug 27 2021

The National Weather Service in Sterling Virginia has issued a

* Severe Thunderstorm Warning for...
  Northern Carroll County in north central Maryland...
  Northeastern Frederick County in north central Maryland...

* Until 500 PM EDT.

* At 414 PM EDT, a severe thunderstorm was located near Taneytown, or
  9 miles west of Westminster, moving northeast at 15 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damaging winds will cause some trees and large branches 
           to fall. This could injure those outdoors, as well as 
           damage homes and vehicles. Roadways may become blocked by 
           downed trees. Localized power outages are possible. 
           Unsecured light objects may become projectiles.

* Locations impacted include...
  Westminster, Emmitsburg, Taneytown, Hampstead, Manchester, New
  Windsor, Union Bridge, Harney, Linwood, Uniontown, Wagners Mill,
  Greenmount, Keysville and Keymar.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3961 7683 3958 7684 3949 7717 3971 7734
      3972 7731 3972 7691
TIME...MOT...LOC 2014Z 237DEG 13KT 3957 7719 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

LFR
3 follow-up statements
534 
WWUS51 KLWX 272030
SVSLWX

Severe Weather Statement
National Weather Service Baltimore MD/Washington DC
430 PM EDT Fri Aug 27 2021

MDC021-272040-
/O.CAN.KLWX.SV.W.0464.000000T0000Z-210827T2100Z/
Frederick MD-
430 PM EDT Fri Aug 27 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN FREDERICK COUNTY
IN NORTH CENTRAL MARYLAND IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been
cancelled.

LAT...LON 3961 7683 3958 7684 3951 7713 3956 7717
      3964 7727 3972 7719 3972 7691
TIME...MOT...LOC 2030Z 237DEG 13KT 3960 7713 

$$

MDC013-272100-
/O.CON.KLWX.SV.W.0464.000000T0000Z-210827T2100Z/
Carroll MD-
430 PM EDT Fri Aug 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM EDT
FOR NORTHERN CARROLL COUNTY...

At 430 PM EDT, a severe thunderstorm was located near Taneytown, or
near Westminster, moving northeast at 15 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damaging winds will cause some trees and large branches to 
         fall. This could injure those outdoors, as well as damage 
         homes and vehicles. Roadways may become blocked by downed 
         trees. Localized power outages are possible. Unsecured 
         light objects may become projectiles.

Locations impacted include...
Westminster, Taneytown, Hampstead, Manchester, New Windsor, Union
Bridge, Linwood, Uniontown, Wagners Mill, Greenmount and Keysville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3961 7683 3958 7684 3951 7713 3956 7717
      3964 7727 3972 7719 3972 7691
TIME...MOT...LOC 2030Z 237DEG 13KT 3960 7713 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

LFR
402 
WWUS51 KLWX 272046
SVSLWX

Severe Weather Statement
National Weather Service Baltimore MD/Washington DC
446 PM EDT Fri Aug 27 2021

MDC013-272100-
/O.CON.KLWX.SV.W.0464.000000T0000Z-210827T2100Z/
Carroll MD-
446 PM EDT Fri Aug 27 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM EDT
FOR NORTHEASTERN CARROLL COUNTY...

At 445 PM EDT, a severe thunderstorm was located near Taneytown, or
near Westminster, moving northeast at 15 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damaging winds will cause some trees and large branches to 
         fall. This could injure those outdoors, as well as damage 
         homes and vehicles. Roadways may become blocked by downed 
         trees. Localized power outages are possible. Unsecured 
         light objects may become projectiles.

Locations impacted include...
Westminster, Taneytown, Hampstead, Manchester and Greenmount. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3961 7683 3961 7706 3962 7718 3965 7718
      3972 7719 3972 7691
TIME...MOT...LOC 2045Z 237DEG 13KT 3962 7709 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

RCM
577 
WWUS51 KLWX 272050
SVSLWX

Severe Weather Statement
National Weather Service Baltimore MD/Washington DC
450 PM EDT Fri Aug 27 2021

MDC013-272100-
/O.EXP.KLWX.SV.W.0464.000000T0000Z-210827T2100Z/
Carroll MD-
450 PM EDT Fri Aug 27 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CARROLL COUNTY
WILL EXPIRE AT 500 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However heavy rain
is still possible with this thunderstorm.

LAT...LON 3961 7683 3961 7706 3962 7718 3965 7718
      3972 7719 3972 7691
TIME...MOT...LOC 2050Z 237DEG 13KT 3963 7707 

$$

LFR

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Aug 27, 2:55 PM EDT, 1 hour 19 minutes earlier.

Area forecast discussion, Aug 27, 2:55 PM EDT, 1 hour 19 minutes before
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
255 PM EDT Fri Aug 27 2021

.SYNOPSIS...
A weak cold front will move into the area tonight into
Saturday. The boundary will stall over our area through early
next week. Another boundary may impact our region midway through
next week. A tropical influence of moisture from a tropical
system moving into the Gulf of Mexico this week could enhance
showers and thunderstorms during the middle to later part of
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A shortwave will move east along the Mason-Dixon and bring a
threat of heavy showers and strong to severe thunderstorms to
the northern half of our region. At the same time, a pressure
trough will be over our area. A light flow that means more
boundaries from terrain circulation and the Bay/Potomac breezes
are expected as well.

Showers and a couple of thunderstorms, producing heavy rainfall,
are occurring and will continue to develop across the northern
half of our region the remainder of this afternoon into mid-
evening. The strongest thunderstorms have not only produced
small hail and occasional lightning but rainfall rates of 2 to 3
inches per hour. Additional showers and thunderstorms will
produce similar threats during the next 4 to 6 hours from
central Maryland and eastern West Virginia to northeast Maryland
and into southern Maryland. Places that do encounter one of
these heavier downpours will experience temperatures dropping 7
to 10 degrees in 1 hour. This would add some relief. However,
areas that remain dry with some sunshine can expect temperatures
in the lower to middle 90s with high indice values near 100.

Strong to extreme instability this afternoon and evening with
1500-2500 J/kg MLCAPE. Mid- level lapse rates are 6 C/km and
should be steepening slightly late this afternoon. Dew points
near or in excess of 70 degrees and PWs exceeding 2 inches
should result in ample MLCAPE of 2500-3500 J/kg east of I-81.
Despite weak flow of 15 kts in the mid-levels, the combination
of strong convergence along the lee trough couple with added
convergence, lift and modest low level directional shear across
bay/river breeze circulations should be enough to maintain a
volatile structure to thunderstorm clusters capable of
producing scattered wind damage; a couple of considerable
microbursts can't be completely ruled out give a slight
enhancement of about 20 kts at 700 mb around the northern
periphery of ridging off the Carolinas and DCAPE around 1000
J/kg. Large hail cannot be ruled out either given the strong to
extreme instability. HREF probabilities of updrafts speeds >20
m/s of 50-70% support the notion of scattered severe
thunderstorm coverage this afternoon and evening.

A Flash Flood Watch remains in effect for northeastern MD as
well as the Baltimore and Washington Metro areas. Thunderstorms
are most likely to produce flash flooding across these areas,
where the best moisture is. Also, as the shortwave passes
through, it does appear that it will be strong enough for low
pressure to develop. Training convection expected across the
Baltimore metro area into northeastern MD. Farther southwest,
convection may be a little more progressive across the DC area,
but there may be a couple rounds, and very heavy rainfall rates
may still cause issues with flash flooding in urban areas even
if it is somewhat progressive. That's why the watch was issued
for this area. An expansion of the watch may be needed in area
to the northwest into north-central MD, or even across portions
of southern MD. Will continue to monitor this possibility
throughout the day.

The shortwave will move off to the east later this evening and
overnight. Convection should dissipate this evening for most
areas, but it may hang around for a bit across northeastern MD
before dissipating overnight. Areas of fog and low clouds are
possible overnight.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Previous discussion...
High pressure will build to our north and east Saturday behind a
shortwave, and this will cause a weak cold front to advance
farther southwest, most likely stalling out near the Potomac
River. More showers and thunderstorms are possible Saturday
across anywhere, but the best chance for stronger to perhaps
even severe storms as well as an isolated flash flood threat
will be near and southwest of the boundary (most likely
southwest of the Potomac River into the Potomac Highlands and
central VA).

Convection will likely dissipate later Saturday night, but more
low clouds and fog area possible Fog may be locally dense as
well.

The boundary will remain nearly stationary for Sunday, but it
should weaken as upper-level high builds closer. Therefore, it
will likely turn out warm and humid. More showers and
thunderstorms are possible, with the best chance for a stronger
storm being south and west of the Potomac River. Coverage may be
more isolated or widely scattered since there will be height
rises from the building upper-level high.

More warm and humid conditions are expected Sunday night as
convection wanes, and there may be areas of low clouds and fog.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
The upper-level ridge will start to break down on Monday across the
southeast US, while a trough moves east out of the Midwest. The
stalled frontal boundary will still be close to the CWA Monday into
Tuesday. Several disturbances will ride along the front through
Midweek providing the forcing for greater coverage of showers and
thunderstorms at times. There will be weak flow and ample moisture,
so isolated flash flooding appears to be the primary threat. The
potential for at least isolated severe thunderstorms is also
possible, though confidence remains low due to subtle mesoscale
features not yet resolved.

By midweek, attention will be turned to the remnants of what is now
Hurricane Ida (please consult hurricanes.gov for the latest forecast
from NHC). The current NHC forecast has Hurricane Ida making
landfall along the Gulf Coast region and then being steered
northeast by the trough that will be moving through the Ohio Valley.
This brings the remnants of Ida in the vicinity of the Mid Atlantic
by the middle of next week. With a stalled frontal boundary nearby,
an influx of tropical moisture to an airmass with preceding
anomalous moisture, and the trough providing additional ascent for
precipitation, there could be an elevated flood/flash flood risk
across parts of the Mid Atlantic, including parts of the local
region. The exact track of the remnants of Ida and other
aforementioned features will determine the exact timing, amounts,
and locations of the associated rainfall, so please monitor the
latest forecast for updates.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
Thunderstorms late this afternoon into this evening along the
Bay/Potomac breezes near KDCA, KBWI, and KMTN, as well as near
KIAD late this afternoon, may produce gusty winds and subVFR
cigs/vsbys.

Convection will wane overnight, but patchy fog is possible
toward morning. Fog may be a little more widespread compared to
recent days due to more rainfall expected this afternoon/evening.
IFR vsbys are possible. Low clouds may impact the northeastern
terminals Saturday morning, especially KBWI, KMTN and possibly
KDCA and KIAD. MVFR cigs are most likely.

More showers and thunderstorms are possible Saturday
afternoon/evening as well as Sunday afternoon/evening. The best
chance for a stronger storm will be across KMRB and KCHO. Areas
of low clouds and fog are likely Saturday night into Sunday
morning, and possible Sunday night.

Flight restrictions are possible at times Monday and Tuesday due to
showers and thunderstorms in the area due to a stalled frontal
boundary over the Mid Atlantic.

&&

.MARINE...
A weak cold front will approach tonight before passing through
Saturday. Light southerly winds this evening will likely turn
to the north and northeast later tonight through Saturday. Winds
should remain below SCA criteria, but gusts may be close for a
period later Saturday into Saturday night due to a weak pressure
surge.

Light onshore winds are expected Sunday through Sunday night.

Thunderstorms are likely over the water this afternoon and
evening, and some may cause gusty to damaging wind gusts. More
thunderstorms are possible Saturday afternoon and evening, and
again Sunday afternoon and evening, but coverage may be more
isolated or scattered.

Winds will remain below SCA criteria for the majority of Monday and
Tuesday. However, showers and thunderstorms could result in gusty
winds prompting SMWs or MWSs during the afternoon and evening both
days.

&&

.TIDES/COASTAL FLOODING...
A light southerly flow may increase as it turns north and
northeast Saturday into Saturday night, before turning light
again but remaining onshore Sunday. This will cause elevated
water levels. Confidence for minor flooding is low at this time
since the flow will be light, but it may be close for sensitive
areas.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Flash Flood Watch until 11 PM EDT this evening for DCZ001.
MD...Flash Flood Watch until 1 AM EDT Saturday for MDZ006-008-011-
     014-507-508.
     Flash Flood Watch until 11 PM EDT this evening for MDZ013-504-
     506.
VA...Flash Flood Watch until 11 PM EDT this evening for VAZ053-054.
WV...None.
MARINE...Flash Flood Watch until 11 PM EDT this evening for ANZ535.

&&

SYNOPSIS...BJL
NEAR TERM...BJL/KLW
SHORT TERM...BJL
LONG TERM...CPB
AVIATION...KLW/CPB
MARINE...KLW/CPB
TIDES/COASTAL FLOODING...
Hazardous weather outlook, Aug 27, 5:45 AM EDT, 10 hours 29 minutes before
Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
545 AM EDT Fri Aug 27 2021

ANZ530>543-DCZ001-MDZ008-011-013-014-016>018-504-506-508-
VAZ052>057-281000-
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-
545 AM EDT Fri Aug 27 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...Today and Tonight

Severe storms are possible this afternoon and evening, with
damaging winds being the primary threat.

A Flash Flood Watch is in effect for the Baltimore and Washington
Metropolitan areas as well as northeastern Maryland for this
afternoon into tonight. Scattered instances of flash flooding are
possible due to heavy rain from thunderstorms. Elsewhere, isolated
instances of flash flooding are possible.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Isolated severe thunderstorms are possible during the afternoon
and evening hours Saturday and Sunday, and again for Tuesday.
Scattered severe storms are possible Monday.

Isolated instances of flash flooding are possible Saturday through
Tuesday, and scattered instances of flash flooding are possible
Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.

MDZ003>006-503-505-507-VAZ025>031-036>040-050-051-501-502-505>508-
WVZ050>053-055-281000-
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-
545 AM EDT Fri Aug 27 2021

This Hazardous Weather Outlook is for portions of eastern West
Virginia, northern and central Virginia, and central and western
Maryland.

.DAY ONE...Today and Tonight

Severe storms are possible this afternoon and evening, with
damaging winds being the primary threat. The best chance for
severe storms will be near and east of the Interstate 81 corridor
across eastern West Virginia, northern Virginia, and into central
Maryland.

A Flash Flood Watch is in effect for portions of central Maryland
near Washington and Baltimore. Scattered instances of flash
flooding are possible due to heavy rain from thunderstorms.
Elsewhere, isolated instances of flash flooding are possible.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Isolated severe thunderstorms are possible during the afternoon
and evening hours Saturday and Sunday, and again for Tuesday.
Scattered severe storms are possible Monday.

Isolated instances of flash flooding are possible Saturday through
Tuesday, and scattered instances of flash flooding are possible
Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.

MDZ001-501-502-VAZ503-504-WVZ501>506-281000-
Garrett-Extreme Western Allegany-Central and Eastern Allegany-
Western Highland-Eastern Highland-Western Grant-Eastern Grant-
Western Mineral-Eastern Mineral-Western Pendleton-
Eastern Pendleton-
545 AM EDT Fri Aug 27 2021

This Hazardous Weather Outlook is for the Allegheny Front
counties in western Maryland, eastern West Virginia, and Highland
County Virginia.

.DAY ONE...Today and Tonight

Isolated instances of flash flooding and severe storms are
possible this afternoon and evening.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Isolated severe thunderstorms are possible during the afternoon
and evening hours Saturday and Sunday, and again for Tuesday.
Scattered severe storms are possible Monday.

Isolated instances of flash flooding are possible Saturday through
Tuesday, and scattered instances of flash flooding are possible
Wednesday.

.SPOTTER INFORMATION STATEMENT...

Limited spotter activation may be needed this afternoon and
evening.

In the hours before

Local storm report, Aug 27, 11:11 AM EDT, 5 hours 3 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1111 AM EDT FRI AUG 27 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0135 PM     MARINE TSTM WIND QUANTICO MARINE CORP    38.51N  77.30W
08/26/2021  E39 MPH          PRINCE WILLIAM     VA   AWOS

0143 PM     TSTM WND DMG     1 WSW TRIANGLE          38.54N  77.34W
08/26/2021                   PRINCE WILLIAM     VA   EMERGENCY MNGR

            TREE DOWN ON ROUTE 1 NEAR THE INTERSECTION WITH JOPLIN
            ROAD

0148 PM     TSTM WND DMG     3 ENE GARRISONVILLE     38.51N  77.37W
08/26/2021                   STAFFORD           VA   DEPT OF HIGHWAYS

            TREE DOWN ON NORTHBOUND US-1 JEFFERSON DAVIS HIGHWAY
            NEAR VA-637 TELEGRAPH ROAD.

0150 PM     TSTM WND DMG     1 W WIDEWATER           38.46N  77.34W
08/26/2021                   STAFFORD           VA   911 CALL CENTER

            TREE DOWN ON POWER LINES IN THE 100 BLOCK OF VA-635
            DECATUR ROAD.

0230 PM     TSTM WND DMG     2 SW STAFFORD           38.40N  77.43W
08/26/2021                   STAFFORD           VA   911 CALL CENTER

            TREES DOWN NEAR THE INTERSECTION OF US-1 JEFFERSON
            DAVIS HIGHWAY AND SHADY HILL LANE.

0240 PM     TSTM WND DMG     3 NW LEELAND            38.38N  77.47W
08/26/2021                   STAFFORD           VA   911 CALL CENTER

            TREE DOWN IN THE 100 BLOCK OF PINE VIEW DRIVE.

0240 PM     TSTM WND DMG     4 SE STAFFORD           38.38N  77.36W
08/26/2021                   STAFFORD           VA   911 CALL CENTER

            TREES DOWN IN THE 2100 BLOCK OF VA-608 BROOKE ROAD, AND
            NEAR THE INTERSECTION OF VA-608 BROOKE ROAD AND VA-628
            ESKIMO HILL ROAD.

0240 PM     TSTM WND DMG     1 NE FALMOUTH           38.34N  77.45W
08/26/2021                   STAFFORD           VA   DEPT OF HIGHWAYS

            TREE DOWN ON NORTHBOUND VA-627 FORBES STREET NEAR
            THOMAS JEFFERSON PLACE.

0240 PM     TSTM WND DMG     3 WNW LOWER MARLBORO    38.68N  76.72W
08/26/2021                   PRINCE GEORGES     MD   DEPT OF HIGHWAYS

            TREE DOWN ON NORTHBOUND MD-382 CROOM ROAD AT RIVER
            AIRPORT ROAD.

0334 PM     TSTM WND DMG     1 W ALEXANDRIA          38.82N  77.10W
08/26/2021                   CITY OF ALEXANDRIA VA   EMERGENCY MNGR

            TREE DOWN ON THE 1900 BLOCK OF SOUTH HOWARD STREET

0335 PM     FLOOD            1 NE FALMOUTH           38.35N  77.45W
08/26/2021                   STAFFORD           VA   DEPT OF HIGHWAYS

            VA-627 FORBES STREET BLOCKED DUE TO STANDING WATER.

0343 PM     HAIL             1 SW ROSSLYN            38.89N  77.08W
08/26/2021  M0.75 INCH       ARLINGTON          VA   BROADCAST MEDIA

0343 PM     TSTM WND DMG     BARCROFT                38.86N  77.10W
08/26/2021                   ARLINGTON          VA   EMERGENCY MNGR

            MULTIPLE TREES DOWN NEAR THE INTERSECTION OF 14TH
            STREET AND SOUTH POLLARD STREET

0357 PM     TSTM WND DMG     2 ESE KLINE GAP         39.07N  79.16W
08/26/2021                   GRANT              WV   TRAINED SPOTTER

            TREE DOWN ON HOUSE ON THE 100 BLOCK OF BEAGLE BOOT LANE

0357 PM     TSTM WND DMG     1 NE NATIONAL ZOO       38.94N  77.04W
08/26/2021                   DISTRICT OF COLUMB DC   BROADCAST MEDIA

            LARGE TREES DOWN WITH AT LEAST ONE SNAPPED ON 16TH
            STREET NORTHWEST NEAR PINEY BRANCH.

0358 PM     TSTM WND DMG     1 SE MAYSVILLE          39.10N  79.15W
08/26/2021                   GRANT              WV   EMERGENCY MNGR

            2 TREES DOWN ALONG LUNICE CREEK HIGHWAY JUST SE OF
            MAYSVILLE.

0400 PM     TSTM WND DMG     2 NW CATHOLIC UNIVERSIT 38.96N  77.03W
08/26/2021                   DISTRICT OF COLUMB DC   BROADCAST MEDIA

            TREES DOWN ON NORTHBOUND US-29 GEORGIA AVENUE NORTHWEST
            NEAR JEFFERSON STREET NORTHWEST.

0405 PM     TSTM WND DMG     1 E CHERRYDALE          38.90N  77.09W
08/26/2021                   ARLINGTON          VA   DEPT OF HIGHWAYS

            TREES DOWN ON I-66 CUSTIS MEMORIAL PARKWAY NEAR MILE
            MARKER 73.

0405 PM     TSTM WND DMG     1 ENE CHERRYDALE        38.90N  77.10W
08/26/2021                   ARLINGTON          VA   911 CALL CENTER

            TWO TO THREE DOZEN REPORTS OF TREES AND WIRES DOWN IN
            ARLINGTON.

0405 PM     TSTM WND DMG     1 NE AMERICAN UNIVERSIT 38.95N  77.07W
08/26/2021                   DISTRICT OF COLUMB DC   911 CALL CENTER

            THERE WERE ABOUT TWO DOZEN REPORTS OF TREES AND WIRES
            BLOWN DOWN, MAINLY ACROSS NORTHWEST DC.

0410 PM     TSTM WND DMG     1 ENE HYATTSVILLE       38.96N  76.94W
08/26/2021                   PRINCE GEORGES     MD   DEPT OF HIGHWAYS

            TREE AND WIRES DOWN NEAR THE INTERSECTION OF US-1
            BALTIMORE AVENUE AND MD-410 EAST-WEST HIGHWAY.

0412 PM     TSTM WND DMG     1 WNW AMERICAN UNIVERSI 38.94N  77.10W
08/26/2021                   DISTRICT OF COLUMB DC   FIRE DEPT/RESCUE

            TREE ON A HOUSE IN THE 4100 BLOCK OF FORDHAM ROAD
            NORTHWEST.

0415 PM     FLOOD            2 ESE ARLINGTON         38.87N  77.07W
08/26/2021                   ARLINGTON          VA   911 CALL CENTER

            HIGH STANDING WATER PARTIALLY BLOCKING VA-244 COLUMBIA
            PIKE NEAR VA-27 SOUTH WASHINGTON BOULEVARD.

0417 PM     TSTM WND DMG     1 WNW LITTLE FALLS      38.94N  77.13W
08/26/2021                   FAIRFAX            VA   BROADCAST MEDIA

            TREES DOWN ON SOUTHBOUND GEORGE WASHINGTON PARKWAY AT
            VA-123 DOLLEY MADISON BOULEVARD/CHAIN BRIDGE ROAD.

0426 PM     TSTM WND DMG     1 ENE THE AMERICAN LEGI 38.97N  77.17W
08/26/2021                   MONTGOMERY         MD   BROADCAST MEDIA

            TREES DOWN ON WESTBOUND MACARTHUR BOULEVARD NEAR
            PERSIMMON TREE ROAD.

0457 PM     FLOOD            4 NE STONES CORNER      38.38N  77.34W
08/26/2021                   STAFFORD           VA   911 CALL CENTER

            VA-623 HARRELL ROAD AND VA-608 BROOKE ROAD BLOCKED BY
            HIGH WATER AT CRESTWOOD LANE.

0515 PM     TSTM WND DMG     KEYSER                  39.44N  78.98W
08/26/2021                   MINERAL            WV   911 CALL CENTER

            TWO TREES DOWN IN KEYSER, INCLUDING ONE ONTO A HOUSE.

0527 PM     FLOOD            1 ENE RIVERCREST        38.92N  77.11W
08/26/2021                   DISTRICT OF COLUMB DC   BROADCAST MEDIA

            CANAL ROAD NORTHWEST PARTIALLY BLOCKED BY HIGH WATER
            NEAR ARIZONA AVENUE NORTHWEST.

0530 PM     TSTM WND DMG     3 SSW RIO               39.09N  78.70W
08/26/2021                   HARDY              WV   911 CALL CENTER

            TREE DOWN ALONG WV-29 SPERRYS RUNS ROAD.

0532 PM     TSTM WND DMG     2 NW LONG GREEN         39.49N  76.54W
08/26/2021                   BALTIMORE          MD   TRAINED SPOTTER

            TREE DOWN AND LARGE BRANCHES DOWN ON BLENHEIM ROAD
            NORTH.

0610 PM     TSTM WND DMG     FLINTSTONE              39.70N  78.57W
08/26/2021                   ALLEGANY           MD   911 CALL CENTER

            NUMEROUS TREES DOWN IN THE FLINTSTONE AREA.

&&

EVENT NUMBER LWX2105606 LWX2105608 LWX2105607 LWX2105609 LWX2105610
LWX2105626 LWX2105627 LWX2105629 LWX2105632 LWX2105617 LWX2105611
LWX2105612 LWX2105615 LWX2105613 LWX2105620 LWX2105614 LWX2105624
LWX2105616 LWX2105622 LWX2105625 LWX2105618 LWX2105623 LWX2105621
LWX2105619 LWX2105631 LWX2105628 LWX2105635 LWX2105630 LWX2105636
LWX2105633 LWX2105634

DH
Local storm report, Aug 27, 2:51 PM EDT, 1 hour 23 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
251 PM EDT FRI AUG 27 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0744 PM     TSTM WND DMG     2 NNE CEDAR GROVE       39.29N  78.17W
08/26/2021                   FREDERICK          VA   EMERGENCY MNGR

            2 CHERRY TREES UPROOTED AND 2 TREES SNAPPED NEAR THE
            INTERSECTION OF HUNSPER LANE AND ENCHANTING DRIVE

&&

EVENT NUMBER LWX2105637

ADM
Local storm report, Aug 27, 3:33 PM EDT, 41 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
333 PM EDT FRI AUG 27 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0316 PM     TSTM WND GST     1 NW GAITHERSBURG       39.15N  77.24W
08/27/2021  M62 MPH          MONTGOMERY         MD   MESONET

&&

EVENT NUMBER LWX2105638

CPB
Local storm report, Aug 27, 3:58 PM EDT, 16 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
358 PM EDT FRI AUG 27 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0326 PM     TSTM WND DMG     THE AMERICAN LEGION MEM 38.96N  77.18W
08/27/2021                   FAIRFAX            VA   BROADCAST MEDIA

            TREE DOWN ON THE NORTHBOUND RAMP OF GEORGE WASHINGTON
            PARKWAY TO I-495.

&&

EVENT NUMBER LWX2105639

CPB

The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 27, 2:56 AM EDTFlash Flood WatchLWXAnne Arundel, Baltimore, Cecil, Harford, Howard, Montgomery and 2 more17 hr
Aug 27, 2:35 PM EDTSevere Thunderstorm WarningLWXMontgomery40 min
Aug 27, 3:05 PM EDTSevere Thunderstorm WarningLWXMontgomery40 min
Aug 27, 3:25 PM EDTSevere Thunderstorm WarningLWXFrederick30 min
Aug 27, 3:36 PM EDTSevere Thunderstorm Warning Considerable damage threatLWXMontgomery, Prince George's19 min
Aug 27, 4:11 PM EDTAreal Flood WarningLWXMontgomery, Prince George's3 hr
Aug 27, 4:44 PM EDTAreal Flood WarningLWXPrince George's3 hr
Aug 27, 4:59 PM EDTSevere Thunderstorm WarningLWXAnne Arundel33 min
Aug 27, 5:06 PM EDTSevere Thunderstorm WarningLWXBaltimore, Carroll20 min
Aug 27, 5:21 PM EDTSevere Thunderstorm WarningLWXCharles, Prince George's39 min
Aug 27, 5:52 PM EDTSevere Thunderstorm WarningLWXBaltimore, Harford53 min
Aug 27, 6:10 PM EDTSevere Thunderstorm WarningLWXCharles32 min
Aug 27, 6:11 PM EDTAreal Flood WarningLWXCharles, Prince George's3 hr
Aug 27, 6:13 PM EDTAreal Flood WarningLWXBaltimore, Harford3 hr
Aug 27, 6:17 PM EDTSevere Thunderstorm WarningLWXBaltimore, Harford29 min
Aug 27, 6:28 PM EDTSevere Thunderstorm WarningLWXCalvert, Charles, Prince George's, Saint Mary's47 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2021Every severe thunderstorm warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.