Alert archive / Virginia / Flash Flood Warnings in 2021

Flash Flood Warning 53, NWS Baltimore/Washington

August 21, 2021Greene County, Virginia

NWS Baltimore/Washington issued this flash flood warning at Aug 21, 2021, 11:15 PM EDT for Greene County, Virginia. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 21, 2021, 11:15 PM EDT (03:15 UTC)
Expired
Aug 22, 2021, 1:22 AM EDT
In force
2 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Greene County, VA

The radar

The Sterling radar (KLWX), 116 km from the middle of the area, began a volume at 03:18 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.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 3.3 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 00:00Z on 2021-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 00:00Z on 2021-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
0 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
23 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

581 
WGUS51 KLWX 220315
FFWLWX
VAC079-220615-
/O.NEW.KLWX.FF.W.0053.210822T0315Z-210822T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Baltimore MD/Washington DC
1115 PM EDT Sat Aug 21 2021

The National Weather Service in Sterling Virginia has issued a

* Flash Flood Warning for...
  Central Greene County in central Virginia...

* Until 215 AM EDT.

* At 1115 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. The expected rainfall rate is 1 to 2 inches in 1 
  hour. 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...
  Stanardsville...                   Lydia...
  Haneytown...                       Amicus...

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.

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

&&

LAT...LON 3839 7852 3838 7850 3836 7848 3834 7846
      3830 7844 3826 7843 3824 7845 3823 7848
      3823 7851 3823 7852 3824 7853 3828 7856
      3831 7859 3832 7859 3833 7857 3834 7855
      3835 7855 3836 7854 3837 7853

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

CJL
1 follow-up statement
086 
WGUS71 KLWX 220522
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
122 AM EDT Sun Aug 22 2021

VAC079-220532-
/O.CAN.KLWX.FF.W.0053.000000T0000Z-210822T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Greene VA-
122 AM EDT Sun Aug 22 2021

...FLASH FLOOD WARNING IS CANCELLED FOR CENTRAL GREENE COUNTY...

The heavy rain has ended. A Flood Warning has replaced the previous 
Flash Flood Warning. Please report observed flooding to local 
emergency services or law enforcement and request they pass this 
information to the National Weather Service when you can do so 
safely.

LAT...LON 3839 7852 3838 7850 3836 7848 3834 7846
      3830 7844 3826 7843 3824 7845 3823 7848
      3823 7851 3823 7852 3824 7853 3828 7856
      3831 7859 3832 7859 3833 7857 3834 7855
      3835 7855 3836 7854 3837 7853

$$

BRO

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 10:20 PM EDTAreal Flood WarningLWXPage2 hr
Aug 21, 10:53 PM EDTAreal Flood WarningLWXAlbemarle, Greene, Page, Rockingham5 hr
Aug 22, 8:36 AM EDTSpecial Marine WarningLWX23 min
Aug 22, 10:55 AM EDTSpecial Marine WarningLWX23 min
Aug 22, 1:08 PM EDTSpecial Marine WarningLWX97 min
Aug 22, 1:52 PM EDTSpecial Marine WarningLWX98 min
Aug 22, 4:10 PM EDTSpecial Marine WarningLWX71 min
Aug 22, 4:37 PM EDTSpecial Marine WarningLWX68 min
Aug 22, 4:41 PM EDTSevere Thunderstorm WarningLWXFairfax49 min
Aug 22, 5:20 PM EDTSpecial Marine WarningLWX32 min

Nearby

Flash Flood Warnings in Virginia, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.