Alert archive / Maryland / Flash Flood Warnings in 2021

Flash Flood Warning 67, NWS Baltimore/Washington

September 1, 2021Cecil County, Harford County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Sep 1, 2021, 3:34 PM EDT for Cecil County, Harford County, Maryland. It was in force for 3 hr. 3 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, 3:34 PM EDT (19:34 UTC)
Expired
Sep 1, 2021, 6:08 PM EDT
In force
3 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Cecil County, MD, Harford County, MD

The radar

The Dover AFB radar (KDOX), 98 km from the middle of the area, began a volume at 19:35 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
Sep 1, 4:58 PM EDTFLOOD2 E North East, MDSEVERAL ROADS CLOSED DUE TO HIGH WATER NEAR NORTH EAST.
Sep 1, 5:24 PM EDTFLOOD1 Ene Aberdeen, MDTHE RAMPS FROM MD-22 ABERDEEN THRUWAY TO US-40 PULASKI HIGHWAY WERE BLOCKED BY HIGH WATER. US-40 PULASKI HIGHWAY WAS CLOSED DUE TO FLOODING JUST TO THE EAST OF MD-22 ABERDEEN THRUWAY TO NEAR ROBIN HOOD ROAD.
Sep 1, 5:38 PM EDTFLOOD1 N Charlestown, MDUS-40 PULASKI HIGHWAY WAS CLOSED IN BOTH DIRECTIONS DUE TO FLOODING BETWEEN PRINCIPIO PARKWAY EAST AND CHARLESTOWN CROSSING BOULEVARD.

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, 7.6 hours before the alert went out and 120 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 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 558 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 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 122 square meters per square second.19395878Sfc1 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
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.

194 
WGUS51 KLWX 011934
FFWLWX
MDC015-025-012230-
/O.NEW.KLWX.FF.W.0067.210901T1934Z-210901T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Sterling Virginia has issued a

* Flash Flood Warning for...
  Cecil County in northeastern Maryland...
  Harford County in northern Maryland...

* Until 630 PM EDT.

* At 334 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2.5 inches of 
  rain have fallen. Additional rainfall amounts of 1 to 3 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...
  Elkton...                          Aberdeen...
  Havre De Grace...                  Aberdeen Proving Ground...
  Calvert...                         Bel Air South...
  Bel Air North...                   Fallston...
  Riverside...                       Kingsville...
  North East...                      Pleasant Hills...
  Jarrettsville...                   Rising Sun...
  Perryman...                        Charlestown...
  Octoraro...                        Conowingo...
  Richardsmere...                    West Nottingham...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3972 7652 3972 7579 3957 7578 3949 7589
      3948 7595 3944 7601 3951 7600 3952 7609
      3949 7611 3946 7605 3944 7604 3934 7624
      3930 7626 3929 7629 3937 7632 3939 7636
      3946 7639 3949 7643 3951 7643 3951 7647

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

$$

BKF
1 follow-up statement
499 
WGUS71 KLWX 012208
FFSLWX

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

MDC015-025-012218-
/O.CAN.KLWX.FF.W.0067.000000T0000Z-210901T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cecil MD-Harford MD-
608 PM EDT Wed Sep 1 2021

...FLASH FLOOD WARNING FOR CECIL AND HARFORD COUNTIES HAS BEEN 
REPLACED WITH A FLOOD WARNING...

LAT...LON 3972 7652 3972 7579 3957 7578 3949 7589
      3948 7595 3944 7601 3951 7600 3952 7609
      3949 7611 3946 7605 3944 7604 3934 7624
      3930 7626 3929 7629 3937 7632 3939 7636
      3946 7639 3949 7643 3951 7643 3951 7647

$$

RCM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 31, 9:06 PM EDTCoastal Flood WatchLWXAnne Arundel22 hr
Aug 31, 9:36 PM EDTRiver Flood WarningLWXWashington68 hr
Aug 31, 9:44 PM EDTRiver Flood WatchLWXFrederick25 hr
Aug 31, 9:44 PM EDTRiver Flood WatchLWXMontgomery48 hr
Aug 31, 9:44 PM EDTRiver Flood WatchLWXWashington25 hr
Aug 31, 9:44 PM EDTRiver Flood WatchLWXMontgomery25 hr
Sep 1, 3:23 AM EDTAreal Flood WarningLWXMontgomery8 hr
Sep 1, 3:24 AM EDTSevere Thunderstorm WarningLWXMontgomery, Prince George's51 min
Sep 1, 3:50 AM EDTAreal Flood WarningLWXMontgomery, Prince George's6 hr
Sep 1, 4:00 AM EDTSevere Thunderstorm WarningLWXAnne Arundel, Prince George's60 min
Sep 1, 4:10 AM EDTAreal Flood WarningLWXAnne Arundel, Baltimore, Howard, City of Baltimore6 hr
Sep 1, 4:34 AM EDTAreal Flood WarningLWXMontgomery6 hr
Sep 1, 4:39 AM EDTAreal Flood WarningLWXAnne Arundel, Baltimore, Howard, City of Baltimore5 hr
Sep 1, 4:50 AM EDTSevere Thunderstorm WarningLWXAnne Arundel, Baltimore, City of Baltimore40 min
Sep 1, 5:41 AM EDTAreal Flood WarningLWXCecil, Harford5 hr
Sep 1, 6:15 AM EDTAreal Flood WarningLWXCecil5 hr
Sep 1, 8:39 AM EDTFlash Flood WarningLWXAllegany, Garrett5 hr
Sep 1, 10:14 AM EDTCoastal Flood AdvisoryLWXAnne Arundel, Baltimore, Calvert, Cecil, Harford, Saint Mary's and 1 more19 hr
Sep 1, 12:52 PM EDTAreal Flood WarningLWXAllegany22 hr
Sep 1, 1:11 PM EDTTornado WarningLWXCharles, Prince George's34 min
Sep 1, 1:23 PM EDTTornado WarningLWXCharles17 min
Sep 1, 1:30 PM EDTAreal Flood WarningLWXCarroll, Frederick, Washington27 hr
Sep 1, 1:31 PM EDTTornado WarningLWXCharles, Saint Mary's29 min
Sep 1, 1:46 PM EDTAreal Flood WarningLWXAllegany, Garrett16 hr
Sep 1, 1:56 PM EDTTornado WarningLWXAnne Arundel, Prince George's34 min
Sep 1, 2:12 PM EDTTornado WarningLWXBaltimore33 min
Sep 1, 2:23 PM EDTTornado WarningLWXBaltimore15 min
Sep 1, 2:26 PM EDTFlash Flood Warning Considerable damage threatLWXCarroll, Frederick6 hr
Sep 1, 2:26 PM EDTTornado WarningLWXBaltimore, Harford14 min
Sep 1, 2:27 PM EDTTornado Warning Tornado observedLWXAnne Arundel15 min
Sep 1, 2:48 PM EDTTornado Warning Tornado observedLWXBaltimore, Harford27 min
Sep 1, 3:10 PM EDTTornado WarningLWXBaltimore16 min
Sep 1, 3:17 PM EDTTornado WarningLWXHarford28 min
Sep 1, 3:25 PM EDTFlash Flood Warning Considerable damage threatLWXCarroll, Frederick5 hr
Sep 1, 3:36 PM EDTWind AdvisoryLWXAllegany, Carroll, Frederick, Washington7 hr
Sep 1, 3:49 PM EDTTornado WarningLWXCecil, Harford26 min
Sep 1, 4:13 PM EDTRiver Flood WatchLWXCecil7 hr
Sep 1, 4:13 PM EDTRiver Flood WarningLWXAllegany7 hr
Sep 1, 4:14 PM EDTRiver Flood WarningLWXAllegany9 hr
Sep 1, 4:37 PM EDTAreal Flood WarningLWXBaltimore, Carroll, Harford13 hr
Sep 1, 5:46 PM EDTTornado WarningLWXCecil29 min
Sep 1, 6:08 PM EDTAreal Flood WarningLWXCecil, Harford17 hr
Sep 1, 6:12 PM EDTTornado WarningLWXCecil19 min
Sep 1, 7:03 PM EDTCoastal Flood WarningLWXAnne Arundel8 hr
Sep 1, 7:27 PM EDTAreal Flood WarningLWXAllegany, Washington15 hr
Sep 1, 7:59 PM EDTAreal Flood WarningLWXCarroll, Frederick2 hr

Nearby

Flash Flood Warnings in Maryland, 2021Every 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.