Alert archive / Virginia / Flash Flood Warnings in 2023

Flash Flood Warning 21, NWS Blacksburg, VA

August 28, 20234 counties in Virginia

NWS Blacksburg, VA issued this flash flood warning at Aug 28, 2023, 12:44 AM EDT for 4 counties in Virginia. It was in force for 5 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 28, 2023, 12:44 AM EDT (04:44 UTC)
Expired: Aug 28, 2023, 5:52 AM EDT
In force: 5 hr
Issued by: NWS Blacksburg, VA
Area: Storm-based polygon
Flood severity: None

Counties City of Martinsville, VA, Franklin County, VA, Henry County, VA, Patrick County, VA

The radar

The Roanoke radar (KFCX), 44 km from the middle of the area, began a volume at 04:47 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

Time	Report	Where	Remark
Aug 28, 1:15 AM EDT	FLASH FLOOD	4 Ese Buffalo Ridge, VA	Pole Branch Creek has exceeded its banks and continues to rise.
Aug 28, 4:00 AM EDT	FLASH FLOOD	Ararat, VA	Several roads are flooded and impassible by creeks several feet out of their banks around the community of Ararat, including a portion of Raven Rock Road.

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, 4.7 hours before the alert went out and 69 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: 502 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 907 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -5 m²/s²
0-3 km storm-relative helicity: -13 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

025 
WGUS51 KRNK 280444
FFWRNK
VAC067-089-141-690-281045-
/O.NEW.KRNK.FF.W.0021.230828T0444Z-230828T1045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Blacksburg VA
1244 AM EDT Mon Aug 28 2023

The National Weather Service in Blacksburg has issued a

* Flash Flood Warning for...
  Henry County in south central Virginia...
  The City of Martinsville in south central Virginia...
  Patrick County in southwestern Virginia...
  Southwestern Franklin County in west central Virginia...

* Until 645 AM EDT Monday.

* At 1244 AM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. The expected rainfall rate is 3 to 5 inches in 1 
  hour. Flash flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Martinsville...                    Stuart...
  Bassett...                         Spencer...
  Ferrum...                          Sydnorsville...
  Axton...

This includes the following locations...
	The Martinsville Speedway and Martinsville Airport.

This includes the following streams and drainages...
  Birds Branch, Ararat River, Archies Creek, Bassett Branch, Beaver 
  Creek, Big Chestnut Creek and Anglin Branch.

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 3694 8007 3683 7968 3682 7965 3679 7966
      3669 7968 3666 7969 3662 7970 3655 8005
      3654 8009 3654 8012 3656 8060 3671 8035
      3672 8022

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...3-5 INCHES IN 1 HOUR

$$

RS

1 follow-up statement

999 
WGUS71 KRNK 280952
FFSRNK

Flash Flood Statement
National Weather Service Blacksburg VA
552 AM EDT Mon Aug 28 2023

VAC067-089-141-690-281002-
/O.CAN.KRNK.FF.W.0021.000000T0000Z-230828T1045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin VA-Henry VA-Patrick VA-City of Martinsville VA-
552 AM EDT Mon Aug 28 2023

...FLASH FLOOD WARNING FOR PATRICK COUNTY HAS BEEN REPLACED WITH A 
FLOOD ADVISORY...
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHWESTERN FRANKLIN AND 
HENRY COUNTIES AND THE CITY OF MARTINSVILLE...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3685 8012 3679 8005 3679 8006 3679 8008
      3678 8009 3675 8009 3674 8009 3672 8009
      3670 8008 3666 8007 3655 8005 3654 8008
      3654 8020 3656 8060 3671 8035 3672 8022
      3685 8013

$$

RS

The office that day

Everything else NWS Blacksburg, VA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 27, 9:50 PM EDT	Special Weather Statement	RNK	Halifax	55 min
Aug 27, 10:49 PM EDT	Flash Flood Warning	RNK	Floyd, Franklin, Patrick	7 hr
Aug 27, 11:57 PM EDT	Flash Flood Warning	RNK	Pittsylvania, City of Danville	6 hr
Aug 28, 2:24 AM EDT	Flash Flood Warning	RNK	Carroll, Patrick	4 hr
Aug 28, 2:58 AM EDT	Flash Flood Warning	RNK	Franklin, Pittsylvania	3 hr
Aug 28, 5:50 AM EDT	Areal Flood Advisory	RNK	Patrick	3 hr
Aug 28, 5:54 AM EDT	Areal Flood Advisory	RNK	Carroll, Patrick	3 hr
Aug 28, 5:59 AM EDT	Areal Flood Advisory	RNK	Franklin, Pittsylvania	3 hr
Aug 28, 8:52 AM EDT	Areal Flood Warning	RNK	Carroll, Floyd, Franklin, Henry, Patrick	6 hr
Aug 28, 4:30 PM EDT	Areal Flood Advisory	RNK	Grayson	3 hr
Aug 28, 4:52 PM EDT	Flash Flood Warning	RNK	Grayson	5 hr
Aug 28, 5:59 PM EDT	Flash Flood Warning	RNK	Smyth	2 hr

Nearby

Flash Flood Warnings in Virginia, 2023 Every flash flood warning in 2023

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.