Alert archive / Tennessee / Flash Flood Warnings in 2021

Flash Flood Warning 56, NWS Nashville, TN

August 21, 2021Marshall County, Maury County, Williamson County, Tennessee

NWS Nashville, TN issued this flash flood warning at Aug 21, 2021, 7:24 PM CDT for Marshall County, Maury County, Williamson County, Tennessee. It was in force for 4 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, 7:24 PM CDT (00:24 UTC)
Expired
Aug 21, 2021, 11:00 PM CDT
In force
4 hr
Issued by
NWS Nashville, TN
Area
Storm-based polygon
Flood severity
None

Counties Marshall County, TN, Maury County, TN, Williamson County, TN

The radar

The Nashville radar (KOHX), 69 km from the middle of the area, began a volume at 00:24 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 21, 7:52 PM CDTFLASH FLOODSanta Fe, TNSANTE FE PIKE IS FLOODED AND IMPASSABLE
Aug 21, 9:05 PM CDTFLASH FLOOD4 Se Santa Fe, TNKNOB CREEK ROAD AT HIGHWAY 7 AND POLK LANE AT REESE CHURCH ROAD BOTH FLOODED AND IMPASSABLE

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 00:00Z, 0.4 hours before the alert went out and 57 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, Nashville Metro, TN at 00:00Z on 2021-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 239 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, Nashville Metro, TN at 00:00Z on 2021-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 69 square meters per square second.193958Sfc1 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
239 J/kg
Mixed-layer CIN
-69 J/kg
Mixed-layer LCL
947 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
69 m²/s²
0-3 km storm-relative helicity
60 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

As transmitted.

098 
WGUS54 KOHX 220024
FFWOHX
TNC117-119-187-220330-
/O.NEW.KOHX.FF.W.0056.210822T0024Z-210822T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Nashville has issued a

* Flash Flood Warning for...
  North Central Marshall County in middle Tennessee...
  Northern Maury County in middle Tennessee...
  Southwestern Williamson County in middle Tennessee...

* Until 1030 PM CDT.

* At 724 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 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...
  Carters Creek including areas near Spring Hill and Neapolis, Snow 
  Creek including Santa Fe, Leipers Creek including McKnight and 
  fly, Columbia, Thompson's Station, I-65 East Of Columbia, and 
  Williamsport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3583 8708 3574 8671 3559 8681 3569 8724
      3581 8719

FLASH FLOOD...RADAR INDICATED

$$

LaRosa
1 follow-up statement
921 
WGUS54 KOHX 220232
FFWOHX
TNC117-119-187-220400-
/O.EXT.KOHX.FF.W.0056.000000T0000Z-210822T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Nashville has extended the

* Flash Flood Warning for...
  North Central Marshall County in middle Tennessee...
  Northern Maury County in middle Tennessee...
  Southwestern Williamson County in middle Tennessee...

* Until 1100 PM CDT.

* At 932 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 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...
  Columbia, Spring Hill, Thompson's Station, I-65 East Of Columbia, 
  Santa Fe and Williamsport.

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 3583 8708 3574 8671 3559 8681 3569 8724
      3581 8719

FLASH FLOOD...RADAR INDICATED

$$

Barnwell

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 7:03 PM CDTAreal Flood AdvisoryOHXGiles, Hickman, Lawrence, Lewis, Marshall, Maury and 1 more4 hr
Aug 21, 7:22 PM CDTSpecial Weather StatementOHXMaury38 min
Aug 21, 7:43 PM CDTFlash Flood WarningOHXLewis, Marshall, Maury3 hr
Aug 21, 9:11 PM CDTAreal Flood AdvisoryOHXBedford, Cannon, Coffee, Marshall, Rutherford, Warren3 hr
Aug 21, 9:59 PM CDTRiver Flood AdvisoryOHXHickman14 hr
Aug 21, 10:34 PM CDTAreal Flood AdvisoryOHXDickson, Hickman, Houston, Humphreys10 hr
Aug 22, 12:33 AM CDTRiver Flood AdvisoryOHXLawrence6 hr

Nearby

Flash Flood Warnings in Tennessee, 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.