Alert archive / Maryland / Flash Flood Warnings in 2021

Flash Flood Warning 65, NWS Baltimore/Washington

September 1, 2021Carroll County, Frederick County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Sep 1, 2021, 2:26 PM EDT for Carroll County, Frederick County, Maryland. It was in force for 6 hr. 9 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: Sep 1, 2021, 2:26 PM EDT (18:26 UTC)
Expired: Sep 1, 2021, 7:59 PM EDT
In force: 6 hr
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Carroll County, MD, Frederick County, MD

The radar

The Sterling radar (KLWX), 71 km from the middle of the area, began a volume at 18:28 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

Time	Report	Where	Remark
Sep 1, 2:59 PM EDT	FLASH FLOOD	3 Nnw Utica, MD	WATER RESCUE NEAR INTERSECTION OF HESSONG BRIDGE ROAD NEAR AND BLACKS MILL ROAD.
Sep 1, 3:10 PM EDT	FLOOD	Thurmont, MD	AT LEAST 20 ROADS CLOSED IN THE NORTHERN PORTION OF FREDERICK COUNTY.
Sep 1, 3:11 PM EDT	FLASH FLOOD	3 Nne Woodsboro, MD	WATER RESCUE NEAR INTERSECTION OF HINEY ROAD AND LEGORE ROAD.
Sep 1, 3:24 PM EDT	FLASH FLOOD	Frederick, MD	AT LEAST SIX SWIFT WATER RESCUES IN FREDERICK COUNTY.
Sep 1, 3:45 PM EDT	FLASH FLOOD	Thurmont, MD	HIGH WATER RESCUE INVOLVING A SCHOOL BUS. TEN STUDENTS AND A DRIVER WERE RESCUED.
Sep 1, 3:47 PM EDT	FLOOD	2 Se Bloomfield, MD	THE RIGHT SIDE OF US-15 SOUTH OF MONOCACY BOULEVARD WAS BLOCKED BY HIGH WATER.
Sep 1, 4:54 PM EDT	FLOOD	2 Nne Woodsboro, MD	MD-194 WOODSBORO PIKE WAS CLOSED IN BOTH DIRECTIONS DUE TO FLOODING NEAR CASH SMITH ROAD.
Sep 1, 5:13 PM EDT	FLOOD	2 Ne Frederick, MD	MD-355 NORTH MARKET STREET WAS CLOSED IN BOTH DIRECTIONS DUE TO FLOODING SOUTH OF MD-26 LIBERTY ROAD (NEAR THE MONOCACY RIVER)
Sep 1, 5:30 PM EDT	FLOOD	2 Ssw Keysville, MD	MD-77 ROCKY BRIDGE ROAD WAS CLOSED IN BOTH DIRECTIONS DUE TO FLOODING NEAR CIRCLE DRIVE (NEAR BIG PIPE CREEK).

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.4 hours before the alert went out and 73 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 558 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 575 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 122 m²/s²
0-3 km storm-relative helicity: 223 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.6

Open this sounding in Storm Lab

The text

As transmitted.

856 
WGUS51 KLWX 011826
FFWLWX
MDC013-021-012130-
/O.NEW.KLWX.FF.W.0065.210901T1826Z-210901T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Baltimore MD/Washington DC
226 PM EDT Wed Sep 1 2021

The National Weather Service in Sterling Virginia has issued a

* Flash Flood Warning for...
  Northwestern Carroll County in north central Maryland...
  Northeastern Frederick County in north central Maryland...

* Until 530 PM EDT.

* At 226 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Frederick...                       Thurmont...
  Emmitsburg...                      Taneytown...
  Walkersville...                    Braddock Heights...
  Discovery-Spring Garden...         Clover Hill...
  Linganore-Bartonsville...          Woodsboro...
  Libertytown...                     Sabillasville...
  Graceham...                        Rocky Ridge...
  Utica...                           Lewistown...
  New Midway...                      Ladiesburg...
  Detour...                          Bloomfield...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3940 7731 3942 7752 3959 7751 3971 7748
      3971 7747 3972 7747 3972 7731 3972 7722
      3972 7716 3960 7720

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

BKF

3 follow-up statements

323 
WGUS71 KLWX 011915
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
315 PM EDT Wed Sep 1 2021

MDC013-021-012130-
/O.CON.KLWX.FF.W.0065.000000T0000Z-210901T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Carroll MD-Frederick MD-
315 PM EDT Wed Sep 1 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM EDT THIS 
AFTERNOON FOR NORTHWESTERN CARROLL AND NORTHEASTERN FREDERICK 
COUNTIES IN NORTH CENTRAL MARYLAND...

At 315 PM EDT, emergency management reported numerous roads closed 
due to high water and several water rescues underway in northern 
Frederick County. Between 3 and 5 inches of rain have fallen. 
Additional rainfall amounts of 1 to 3 inches are possible in the 
warned area. Flash flooding is already occurring.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Emergency management reported.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Frederick...                       Thurmont...
Emmitsburg...                      Taneytown...
Walkersville...                    Braddock Heights...
Discovery-Spring Garden...         Clover Hill...
Linganore-Bartonsville...          Woodsboro...
Libertytown...                     Sabillasville...
Graceham...                        Rocky Ridge...
Utica...                           Lewistown...
New Midway...                      Ladiesburg...
Detour...                          Bloomfield...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3940 7731 3942 7752 3959 7751 3971 7748
      3971 7747 3972 7747 3972 7731 3972 7722
      3972 7716 3960 7720

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

BKF

957 
WGUS51 KLWX 012113
FFWLWX
MDC013-021-020030-
/O.EXT.KLWX.FF.W.0065.000000T0000Z-210902T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Baltimore MD/Washington DC
513 PM EDT Wed Sep 1 2021

The National Weather Service in Sterling Virginia has extended the

* Flash Flood Warning for...
  Northwestern Carroll County in north central Maryland...
  Northeastern Frederick County in north central Maryland...

* Until 830 PM EDT.

* At 513 PM EDT, Flash flooding is already occurring across a large 
  portion of Frederick County. Additional rainfall one to two inches 
  is expected through 7 PM. This will exacerbate the flooding 
  already occurring across the county.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Emergency management reported.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Frederick...                       Thurmont...
  Emmitsburg...                      Taneytown...
  Walkersville...                    Braddock Heights...
  Discovery-Spring Garden...         Clover Hill...
  Linganore-Bartonsville...          Woodsboro...
  Libertytown...                     Sabillasville...
  Graceham...                        Rocky Ridge...
  Utica...                           Lewistown...
  New Midway...                      Ladiesburg...
  Detour...                          Bloomfield...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3940 7731 3942 7752 3959 7751 3971 7748
      3971 7747 3972 7747 3972 7731 3972 7722
      3972 7716 3960 7720

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 3 HOURS

$$

LFR

324 
WGUS71 KLWX 012359
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
759 PM EDT Wed Sep 1 2021

MDC013-021-020009-
/O.CAN.KLWX.FF.W.0065.000000T0000Z-210902T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Carroll MD-Frederick MD-
759 PM EDT Wed Sep 1 2021

...FLASH FLOOD WARNING FOR NORTHWESTERN CARROLL AND NORTHEASTERN 
FREDERICK COUNTIES IN NORTH CENTRAL MARYLAND HAS BEEN REPLACED WITH 
A FLOOD WARNING...

LAT...LON 3940 7731 3942 7752 3959 7751 3971 7748
      3971 7747 3972 7747 3972 7731 3972 7722
      3972 7716 3960 7720

$$

JMG

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 31, 9:06 PM EDT	Coastal Flood Watch	LWX	Anne Arundel	22 hr
Aug 31, 9:36 PM EDT	River Flood Warning	LWX	Washington	68 hr
Aug 31, 9:44 PM EDT	River Flood Watch	LWX	Frederick	25 hr
Aug 31, 9:44 PM EDT	River Flood Watch	LWX	Montgomery	48 hr
Aug 31, 9:44 PM EDT	River Flood Watch	LWX	Washington	25 hr
Aug 31, 9:44 PM EDT	River Flood Watch	LWX	Montgomery	25 hr
Sep 1, 3:23 AM EDT	Areal Flood Warning	LWX	Montgomery	8 hr
Sep 1, 3:24 AM EDT	Severe Thunderstorm Warning	LWX	Montgomery, Prince George's	51 min
Sep 1, 3:50 AM EDT	Areal Flood Warning	LWX	Montgomery, Prince George's	6 hr
Sep 1, 4:00 AM EDT	Severe Thunderstorm Warning	LWX	Anne Arundel, Prince George's	60 min
Sep 1, 4:10 AM EDT	Areal Flood Warning	LWX	Anne Arundel, Baltimore, Howard, City of Baltimore	6 hr
Sep 1, 4:34 AM EDT	Areal Flood Warning	LWX	Montgomery	6 hr
Sep 1, 4:39 AM EDT	Areal Flood Warning	LWX	Anne Arundel, Baltimore, Howard, City of Baltimore	5 hr
Sep 1, 4:50 AM EDT	Severe Thunderstorm Warning	LWX	Anne Arundel, Baltimore, City of Baltimore	40 min
Sep 1, 5:41 AM EDT	Areal Flood Warning	LWX	Cecil, Harford	5 hr
Sep 1, 6:15 AM EDT	Areal Flood Warning	LWX	Cecil	5 hr
Sep 1, 8:39 AM EDT	Flash Flood Warning	LWX	Allegany, Garrett	5 hr
Sep 1, 10:14 AM EDT	Coastal Flood Advisory	LWX	Anne Arundel, Baltimore, Calvert, Cecil, Harford, Saint Mary's and 1 more	19 hr
Sep 1, 12:52 PM EDT	Areal Flood Warning	LWX	Allegany	22 hr
Sep 1, 1:11 PM EDT	Tornado Warning	LWX	Charles, Prince George's	34 min
Sep 1, 1:23 PM EDT	Tornado Warning	LWX	Charles	17 min
Sep 1, 1:30 PM EDT	Areal Flood Warning	LWX	Carroll, Frederick, Washington	27 hr
Sep 1, 1:31 PM EDT	Tornado Warning	LWX	Charles, Saint Mary's	29 min
Sep 1, 1:46 PM EDT	Areal Flood Warning	LWX	Allegany, Garrett	16 hr
Sep 1, 1:56 PM EDT	Tornado Warning	LWX	Anne Arundel, Prince George's	34 min
Sep 1, 2:12 PM EDT	Tornado Warning	LWX	Baltimore	33 min
Sep 1, 2:23 PM EDT	Tornado Warning	LWX	Baltimore	15 min
Sep 1, 2:26 PM EDT	Tornado Warning	LWX	Baltimore, Harford	14 min
Sep 1, 2:27 PM EDT	Tornado Warning Tornado observed	LWX	Anne Arundel	15 min
Sep 1, 2:48 PM EDT	Tornado Warning Tornado observed	LWX	Baltimore, Harford	27 min
Sep 1, 3:10 PM EDT	Tornado Warning	LWX	Baltimore	16 min
Sep 1, 3:17 PM EDT	Tornado Warning	LWX	Harford	28 min
Sep 1, 3:25 PM EDT	Flash Flood Warning Considerable damage threat	LWX	Carroll, Frederick	5 hr
Sep 1, 3:34 PM EDT	Flash Flood Warning Considerable damage threat	LWX	Cecil, Harford	3 hr
Sep 1, 3:36 PM EDT	Wind Advisory	LWX	Allegany, Carroll, Frederick, Washington	7 hr
Sep 1, 3:49 PM EDT	Tornado Warning	LWX	Cecil, Harford	26 min
Sep 1, 4:13 PM EDT	River Flood Watch	LWX	Cecil	7 hr
Sep 1, 4:13 PM EDT	River Flood Warning	LWX	Allegany	7 hr
Sep 1, 4:14 PM EDT	River Flood Warning	LWX	Allegany	9 hr
Sep 1, 4:37 PM EDT	Areal Flood Warning	LWX	Baltimore, Carroll, Harford	13 hr
Sep 1, 5:46 PM EDT	Tornado Warning	LWX	Cecil	29 min
Sep 1, 6:08 PM EDT	Areal Flood Warning	LWX	Cecil, Harford	17 hr
Sep 1, 6:12 PM EDT	Tornado Warning	LWX	Cecil	19 min
Sep 1, 7:03 PM EDT	Coastal Flood Warning	LWX	Anne Arundel	8 hr
Sep 1, 7:27 PM EDT	Areal Flood Warning	LWX	Allegany, Washington	15 hr
Sep 1, 7:59 PM EDT	Areal Flood Warning	LWX	Carroll, Frederick	2 hr

Nearby

Flash Flood Warnings in Maryland, 2021 Every flash flood 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.