Alert archive / Virginia / Flash Flood Warnings in 2021

Flash Flood Warning 31, NWS Baltimore/Washington

July 27, 2021Augusta County, City of Staunton, Virginia

NWS Baltimore/Washington issued this flash flood warning at Jul 27, 2021, 10:40 PM EDT for Augusta County, City of Staunton, Virginia. It was in force for 52 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: Jul 27, 2021, 10:40 PM EDT (02:40 UTC)
Expired: Jul 27, 2021, 11:32 PM EDT
In force: 52 min
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Augusta County, VA, City of Staunton, VA

The radar

The Roanoke radar (KFCX), 160 km from the middle of the area, began a volume at 02:42 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
Jul 27, 10:43 PM EDT	FLASH FLOOD	2 Ssw Staunton, VA	GREENVILLE AVE NEAR RITCHIE BLVD CLOSED DUE TO HIGH WATER.
Jul 27, 10:45 PM EDT	FLASH FLOOD	1 Ssw Staunton, VA	GREENVILLE AVE AT RICHMOND AVE CLOSED DUE TO HIGH WATER.

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

The nearest sounding before it

Roanoke, VA (KRNK), launched 00:00Z, 2.7 hours before the alert went out and 110 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: 372 J/kg
Mixed-layer CIN: -12 J/kg
Mixed-layer LCL: 1853 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: -10 m²/s²
0-3 km storm-relative helicity: 46 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

224 
WGUS51 KLWX 280240
FFWLWX
VAC015-790-280545-
/O.NEW.KLWX.FF.W.0031.210728T0240Z-210728T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Baltimore MD/Washington DC
1040 PM EDT Tue Jul 27 2021

The National Weather Service in Sterling Virginia has issued a

* Flash Flood Warning for...
  Central Augusta County in western Virginia...
  The Western City of Staunton in western Virginia...

* Until 145 AM EDT.

* At 1040 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 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...
  Staunton...                        Swoope...
  Christian...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3820 7920 3821 7917 3819 7910 3819 7909
      3816 7906 3814 7904 3811 7903 3810 7904
      3810 7906 3810 7907 3810 7909 3810 7911
      3811 7913 3812 7915 3813 7918 3815 7920
      3816 7922 3818 7923 3819 7924

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

$$

LFR

1 follow-up statement

076 
WGUS71 KLWX 280332
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
1132 PM EDT Tue Jul 27 2021

VAC015-790-280342-
/O.CAN.KLWX.FF.W.0031.000000T0000Z-210728T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Augusta VA-City of Staunton VA-
1132 PM EDT Tue Jul 27 2021

...FLASH FLOOD WARNING CONVERTED TO FLOOD WARNING FOR CENTRAL 
AUGUSTA COUNTY AND THE WESTERN CITY OF STAUNTON...

The heavy rain has ended, but flooding continues. The flash flood 
warning has been converted to a flood warning.

LAT...LON 3820 7920 3821 7917 3819 7910 3819 7909
      3816 7906 3814 7904 3811 7903 3810 7904
      3810 7906 3810 7907 3810 7909 3810 7911
      3811 7913 3812 7915 3813 7918 3815 7920
      3816 7922 3818 7923 3819 7924

$$

RCM

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 10:08 PM EDT	Severe Thunderstorm Warning	LWX	Augusta, City of Staunton	37 min
Jul 27, 10:54 PM EDT	Severe Thunderstorm Warning	LWX	Albemarle, Augusta, Nelson, City of Waynesboro	36 min
Jul 27, 11:24 PM EDT	Severe Thunderstorm Warning	LWX	Albemarle, Nelson	51 min
Jul 27, 11:31 PM EDT	Areal Flood Warning	LWX	Augusta, City of Staunton	2 hr
Jul 27, 11:33 PM EDT	Severe Thunderstorm Warning	LWX	Nelson	42 min
Jul 28, 12:34 AM EDT	Severe Thunderstorm Warning	LWX	Nelson	41 min
Jul 28, 4:31 PM EDT	Special Marine Warning	LWX		65 min
Jul 28, 4:47 PM EDT	Special Marine Warning	LWX		38 min
Jul 28, 5:15 PM EDT	Special Marine Warning	LWX		47 min
Jul 28, 6:27 PM EDT	Severe Thunderstorm Warning	LWX	Clarke, Loudoun	14 min

Nearby

Flash Flood Warnings in Virginia, 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.