Alert archive / Tennessee / Flash Flood Warnings in 2021

Flash Flood Warning 55, NWS Nashville, TN

August 21, 20214 counties in Tennessee

NWS Nashville, TN issued this flash flood warning at Aug 21, 2021, 5:58 PM CDT for 4 counties in Tennessee. It was in force for 3 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 21, 2021, 5:58 PM CDT (22:58 UTC)
Expired: Aug 21, 2021, 9:00 PM CDT
In force: 3 hr
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Flood severity: None

Counties Cheatham County, TN, Dickson County, TN, Houston County, TN, Montgomery County, TN

The radar

The Ft Campbell radar (KHPX), 52 km from the middle of the area, began a volume at 22:58 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 21, 6:00 PM CDT	FLASH FLOOD	5 Nnw Slayden, TN	REPORT OF SWIFT WATER RESCUSES ONGOING AND MULTIPLE ROADS UNDERWATER IN SOUTHERN MONTGOMERY COUNTY.
Aug 21, 8:00 PM CDT	HEAVY RAIN 11.6	Dickson, TN

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

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 11.0 hours before the alert went out and 76 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: 1243 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 488 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: -5 m²/s²
0-3 km storm-relative helicity: 41 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

As transmitted.

403 
WGUS54 KOHX 212258
FFWOHX
TNC021-043-083-125-220200-
/O.NEW.KOHX.FF.W.0055.210821T2258Z-210822T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
558 PM CDT Sat Aug 21 2021

The National Weather Service in Nashville has issued a

* Flash Flood Warning for...
  Northwestern Cheatham County in middle Tennessee...
  Dickson County in middle Tennessee...
  Northeastern Houston County in middle Tennessee...
  Southern Montgomery County in middle Tennessee...

* Until 900 PM CDT.

* At 558 PM CDT, Doppler radar indicated thunderstorms moving back 
  into the area producing heavy rain. Between 3 and 6 inches of rain 
  have fallen so far today. Flash flooding is already occurring.

  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...
  Dickson, Erin, White Bluff, Burns, Charlotte, Vanleer, Slayden, 
  Cunningham and Cheatham Dam.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3637 8759 3638 8759 3644 8725 3642 8717
      3596 8721 3596 8726 3635 8774

FLASH FLOOD...RADAR INDICATED

$$

Shamburger

1 follow-up statement

040 
WGUS74 KOHX 212326
FFSOHX

Flash Flood Statement
National Weather Service Nashville TN
626 PM CDT Sat Aug 21 2021

TNC021-043-083-125-220200-
/O.CON.KOHX.FF.W.0055.000000T0000Z-210822T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cheatham TN-Dickson TN-Houston TN-Montgomery TN-
626 PM CDT Sat Aug 21 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 9 PM CDT THIS EVENING 
FOR NORTHWESTERN CHEATHAM, DICKSON, NORTHEASTERN HOUSTON AND 
SOUTHERN MONTGOMERY COUNTIES...

At 626 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain continue across the warned area. Between 3 and 9 inches of rain 
have fallen and flash flooding is ongoing.

HAZARD...Life threatening 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...
  Dickson, Erin, White Bluff, Burns, Charlotte, Vanleer, Slayden, 
  Cunningham and Cheatham Dam.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3637 8759 3638 8759 3644 8725 3642 8717
      3596 8721 3596 8726 3635 8774

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

$$

Shamburger

The office that day

Everything else NWS Nashville, TN issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 21, 2:48 AM CDT	Areal Flood Advisory	OHX	Dickson, Hickman, Humphreys, Lewis	2 hr
Aug 21, 3:29 AM CDT	Flash Flood Warning	OHX	Dickson, Hickman, Humphreys	5 hr
Aug 21, 4:10 AM CDT	Areal Flood Advisory	OHX	Giles, Lawrence, Lewis, Maury	3 hr
Aug 21, 4:29 AM CDT	Areal Flood Advisory	OHX	Montgomery, Stewart	3 hr
Aug 21, 4:49 AM CDT	Flash Flood Warning	OHX	Dickson, Hickman, Houston, Humphreys	3 hr
Aug 21, 6:24 AM CDT	Flash Flood Warning	OHX	Houston, Humphreys, Stewart	5 hr
Aug 21, 7:47 AM CDT	Flash Flood Warning EmergencyCatastrophic damage threat	OHX	Dickson, Hickman, Houston, Humphreys	9 hr
Aug 21, 8:39 AM CDT	River Flood Warning	OHX	Hickman	13 hr
Aug 21, 9:41 AM CDT	Areal Flood Advisory	OHX	Hickman, Lewis, Maury	3 hr
Aug 21, 10:12 AM CDT	Flash Flood Warning	OHX	Hickman, Humphreys, Lewis, Maury, Perry	3 hr
Aug 21, 10:17 AM CDT	River Flood Advisory	OHX	Hickman	52 hr
Aug 21, 11:39 AM CDT	Areal Flood Advisory	OHX	Giles, Lawrence, Marshall	3 hr
Aug 21, 12:33 PM CDT	River Flood Warning	OHX	Humphreys	44 hr
Aug 21, 4:40 PM CDT	Areal Flood Advisory	OHX	Houston, Stewart	3 hr
Aug 21, 4:55 PM CDT	Flash Flood Warning	OHX	Dickson, Hickman, Houston, Humphreys	6 hr
Aug 21, 5:07 PM CDT	Flash Flood Warning	OHX	Dickson, Houston, Montgomery, Stewart	4 hr
Aug 21, 5:10 PM CDT	Special Weather Statement	OHX	Houston, Stewart	50 min
Aug 21, 5:30 PM CDT	Special Weather Statement	OHX	Dickson, Houston	45 min
Aug 21, 5:43 PM CDT	Special Weather Statement	OHX	Lawrence	47 min
Aug 21, 5:57 PM CDT	Tornado Warning	OHX	Dickson	16 min
Aug 21, 6:17 PM CDT	Special Weather Statement	OHX	Dickson	43 min
Aug 21, 6:29 PM CDT	Special Weather Statement	OHX	Hickman	31 min
Aug 21, 6:53 PM CDT	Special Weather Statement	OHX	Williamson	37 min

Nearby

Flash Flood Warnings in Tennessee, 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.