Alert archive / West Virginia / Flash Flood Warnings in 2021

Flash Flood Warning 41, NWS Baltimore/Washington

August 16, 2021Berkeley County, Morgan County, West Virginia; Washington County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Aug 16, 2021, 8:47 PM EDT for Berkeley County, Morgan County, West Virginia; Washington County, Maryland. It was in force for 2 hr. 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 16, 2021, 8:47 PM EDT (00:47 UTC)
Expired
Aug 16, 2021, 11:15 PM EDT
In force
2 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Washington County, MD, Berkeley County, WV, Morgan County, WV

The radar

The Sterling radar (KLWX), 88 km from the middle of the area, began a volume at 00:47 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 16, 9:06 PM EDTFLASH FLOOD1 Nne Shady Grove, WVREPORT OF A WATER RESCUE AT 1416 JIM WEST RD. WATER LEVELS QUICKLY RISING, ROUGHLY 4 FEET HIGH, AND RESIDENTS CANNOT REACH THEIR VEHICLE.
Aug 16, 9:47 PM EDTFLOOD3 Ne Shady Grove, WVPOTOMAC RD CLOSED BETWEEN JIM WEST RD AND RIVER RD DUE TO DOWN TREES AND ROAD UNDER WATER.

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 00:00Z, 0.8 hours before the alert went out and 95 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 00:00Z on 2021-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 376 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 2021-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 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
376 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
504 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
34 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

620 
WGUS51 KLWX 170047
FFWLWX
MDC043-WVC003-065-170345-
/O.NEW.KLWX.FF.W.0041.210817T0047Z-210817T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Baltimore MD/Washington DC
847 PM EDT Mon Aug 16 2021

The National Weather Service in Sterling Virginia has issued a

* Flash Flood Warning for...
  North Central Washington County in north central Maryland...
  Northwestern Berkeley County in the panhandle of West Virginia...
  Northeastern Morgan County in the panhandle of West Virginia...

* Until 1145 PM EDT.

* At 847 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen. The expected rainfall rate is 1 to 3 inches in 1 
  hour. 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...
  Pecktonville...                    Big Pool...
  Spruce Pine Hollow...              Spohrs Crossroads...
  Shady Grove...                     New Hope...
  Sleepy Creek...                    Cherry Run...
  Johnsons Mill...                   Highland Ridge...
  Smith Crossroads...                Stotlers Crossroads...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3949 7819 3949 7820 3949 7824 3957 7823
      3966 7817 3972 7807 3972 7806 3972 7801
      3967 7798 3957 7805 3948 7812

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-3 INCHES IN 1 HOUR

$$

BJL
2 follow-up statements
109 
WGUS71 KLWX 170143
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
943 PM EDT Mon Aug 16 2021

MDC043-WVC003-065-170345-
/O.CON.KLWX.FF.W.0041.000000T0000Z-210817T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington MD-Berkeley WV-Morgan WV-
943 PM EDT Mon Aug 16 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 PM EDT THIS 
EVENING FOR NORTH CENTRAL WASHINGTON, NORTHWESTERN BERKELEY AND 
NORTHEASTERN MORGAN COUNTIES...

At 943 PM EDT, Doppler radar indicated that between 3 and 6 inches 
of rain have fallen across most of the warned area. The heaviest 
rain has ended, but streams and creeks will quickly rise due to 
excess runoff. The Morgan County 911 Center has reported high water 
across portions of northeastern Morgan County. 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...
  Pecktonville...                    Big Pool...
Spruce Pine Hollow...              Spohrs Crossroads...
Shady Grove...                     New Hope...
Sleepy Creek...                    Cherry Run...
Johnsons Mill...                   Highland Ridge...
Smith Crossroads...                Stotlers Crossroads...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3949 7819 3949 7820 3949 7824 3957 7823
      3966 7817 3972 7807 3972 7806 3972 7801
      3967 7798 3957 7805 3948 7812

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

$$

BJL
272 
WGUS71 KLWX 170315
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
1115 PM EDT Mon Aug 16 2021

MDC043-WVC003-065-170325-
/O.CAN.KLWX.FF.W.0041.000000T0000Z-210817T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington MD-Berkeley WV-Morgan WV-
1115 PM EDT Mon Aug 16 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTH CENTRAL WASHINGTON, 
NORTHWESTERN BERKELEY AND NORTHEASTERN MORGAN COUNTIES...

Flood waters have receded. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3949 7819 3949 7820 3949 7824 3957 7823
      3966 7817 3972 7807 3972 7806 3972 7801
      3967 7798 3957 7805 3948 7812

$$

BRO

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 1:54 PM EDTFlash Flood WatchLWXBerkeley, Grant, Hampshire, Hardy, Jefferson, Mineral and 2 more27 hr
Aug 16, 9:04 PM EDTFlash Flood Warning Considerable damage threatLWXAllegany2 hr
Aug 16, 11:32 PM EDTFlash Flood Warning Considerable damage threatLWXMontgomery3 hr
Aug 17, 12:39 AM EDTCoastal Flood AdvisoryLWXAnne Arundel100 min
Aug 17, 2:17 AM EDTAreal Flood WarningLWXMontgomery4 hr
Aug 17, 8:54 AM EDTFlash Flood WatchLWXAnne Arundel, Baltimore, Cecil, Harford, City of Baltimore9 hr
Aug 17, 6:40 PM EDTCoastal Flood AdvisoryLWXAnne Arundel, Baltimore, City of Baltimore11 hr

Nearby

Flash Flood Warnings in West Virginia, 2021Flash 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.