Alert archive / Tennessee / Flash Flood Watches in 2021

Flash Flood Watch 8, NWS Nashville, TN

September 15, 202125 counties in Tennessee

NWS Nashville, TN issued this flash flood watch at Sep 15, 2021, 5:55 AM CDT for 25 counties in Tennessee. It took effect at Sep 15, 2021, 7:00 AM CDT. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Sep 15, 2021, 5:55 AM CDT (10:55 UTC)
In effect from
Sep 15, 2021, 7:00 AM CDT
Expired
Sep 15, 2021, 3:56 PM CDT
In force
9 hr
Issued by
NWS Nashville, TN
Flood severity
None
All 25 counties

Cheatham County, TN, Clay County, TN, Davidson County, TN, Dickson County, TN, Giles County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Jackson County, TN, Lawrence County, TN, Lewis County, TN, Macon County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Perry County, TN, Robertson County, TN, Rutherford County, TN, Smith County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Wayne County, TN, Williamson County, TN, Wilson County, TN

The radar

The Nashville radar (KOHX), 41 km from the middle of the area, began a volume at 10:57 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

Nashville Metro, TN (KBNA), launched 00:00Z, 10.9 hours before the alert went out and 31 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 2021-09-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1408 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 2021-09-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -61 square meters per square second.1939Sfc1 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
1408 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
1076 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-61 m²/s²
0-3 km storm-relative helicity
-40 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

114 
WGUS64 KOHX 151055
FFAOHX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Nashville TN
555 AM CDT Wed Sep 15 2021

TNZ005>010-023>031-056>062-093>095-152115-
/O.NEW.KOHX.FF.A.0008.210915T1200Z-210916T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Stewart-Montgomery-Robertson-Sumner-Macon-Clay-Houston-Humphreys-
Dickson-Cheatham-Davidson-Wilson-Trousdale-Smith-Jackson-Perry-
Hickman-Lewis-Williamson-Maury-Marshall-Rutherford-Wayne-Lawrence-
Giles-
Including the cities of Goodlettsville, Carthage, Smyrna, McEwen, 
Clarksville, Pulaski, La Vergne, Springfield, Linden, Waverly, 
Columbia, Brentwood, Nashville, Kingston Springs, Ashland City, 
Dickson, Waynesboro, Hendersonville, Murfreesboro, New Johnsonville, 
Lafayette, Franklin, Gainesboro, Hartsville, Lewisburg, Tennessee 
Ridge, Centerville, Dover, Lawrenceburg, Lobelville, Mount Juliet, 
Lebanon, Clifton, Celina, South Carthage, Hohenwald, Gordonsville, 
Erin, and Gallatin
555 AM CDT Wed Sep 15 2021

...FLASH FLOOD WATCH IN EFFECT THROUGH THIS EVENING...

The National Weather Service in Nashville has issued a

* Flash Flood Watch for a portion of Middle Tennessee, including the 
  following areas, Cheatham, Clay, Davidson, Dickson, Giles, 
  Hickman, Houston, Humphreys, Jackson, Lawrence, Lewis, Macon, 
  Marshall, Maury, Montgomery, Perry, Robertson, Rutherford, Smith, 
  Stewart, Sumner, Trousdale, Wayne, Williamson and Wilson.

* Through this evening.

* 1 To 2 inches will be common, but a quick 3 to 4 inches will be 
  possible in a few places which could lead to Flash Flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

27
1 follow-up statement
924 
WGUS64 KOHX 152056
FFAOHX

Flood Watch
National Weather Service Nashville TN
356 PM CDT Wed Sep 15 2021

TNZ005>010-023>031-056>062-093>095-152200-
/O.CAN.KOHX.FF.A.0008.000000T0000Z-210916T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Stewart-Montgomery-Robertson-Sumner-Macon-Clay-Houston-Humphreys-
Dickson-Cheatham-Davidson-Wilson-Trousdale-Smith-Jackson-Perry-
Hickman-Lewis-Williamson-Maury-Marshall-Rutherford-Wayne-Lawrence-
Giles-
Including the cities of Goodlettsville, Carthage, Smyrna, McEwen, 
Clarksville, Pulaski, La Vergne, Springfield, Linden, Waverly, 
Columbia, Brentwood, Nashville, Kingston Springs, Ashland City, 
Dickson, Waynesboro, Hendersonville, Murfreesboro, New Johnsonville, 
Lafayette, Franklin, Gainesboro, Hartsville, Lewisburg, Tennessee 
Ridge, Centerville, Dover, Lawrenceburg, Lobelville, Mount Juliet, 
Lebanon, Clifton, Celina, South Carthage, Hohenwald, Gordonsville, 
Erin, and Gallatin
356 PM CDT Wed Sep 15 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for a portion of Middle Tennessee, including 
the following areas, Cheatham, Clay, Davidson, Dickson, Giles, 
Hickman, Houston, Humphreys, Jackson, Lawrence, Lewis, Macon, 
Marshall, Maury, Montgomery, Perry, Robertson, Rutherford, Smith, 
Stewart, Sumner, Trousdale, Wayne, Williamson and Wilson has been 
cancelled.

The Flood Watch is cancelled. Flooding is no longer expected to pose 
a threat.

$$

10

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 15, 8:23 AM CDTAreal Flood AdvisoryOHXDickson, Hickman, Lewis, Maury, Perry, Williamson4 hr
Sep 15, 9:33 AM CDTFlash Flood WarningOHXDickson, Hickman, Lewis, Maury, Perry, Williamson117 min
Sep 15, 10:08 AM CDTAreal Flood AdvisoryOHXCheatham, Davidson, Dickson, Robertson, Sumner3 hr
Sep 15, 2:20 PM CDTAreal Flood AdvisoryOHXClay, Jackson, Macon, Overton, Pickett, Putnam and 2 more3 hr
Sep 15, 2:57 PM CDTAreal Flood AdvisoryOHXDeKalb, Jackson, Putnam, Smith, White2 hr

Nearby

Flash Flood Watches in Tennessee, 2021Every flash flood watch 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.