Alert archive / Tennessee / Flash Flood Warnings in 2020

Flash Flood Warning 29, NWS Nashville, TN

September 1, 2020Maury County, Williamson County, Tennessee

NWS Nashville, TN issued this flash flood warning at Sep 1, 2020, 5:27 PM CDT for Maury County, Williamson County, Tennessee. It was in force for 4 hr. 3 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: Sep 1, 2020, 5:27 PM CDT (22:27 UTC)
Expired: Sep 1, 2020, 9:45 PM CDT
In force: 4 hr
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Flood severity: None

Counties Maury County, TN, Williamson County, TN

The radar

The Nashville radar (KOHX), 58 km from the middle of the area, began a volume at 22:28 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
Sep 1, 5:45 PM CDT	FLASH FLOOD	Nolensville, TN	INTERSECTION OF NOLENSVILLE RD AND CLOVERCROFT RD IS IMPASSABLE.
Sep 1, 6:23 PM CDT	FLASH FLOOD	2 Wnw Nolensville, TN	TSPOTTER REPORT OF THE NOLENSVILLE REC CENTER PARKING LOT UNDER WATER.
Sep 1, 6:30 PM CDT	FLASH FLOOD	1 W Nolensville, TN	TSPOTTER REPORT OF BITTOCKS CREEK THAT FLOWS THROUGH BENT CREEK IN NOLENSVILLE WELL OUT OF ITS BANKS

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

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 3 storm reports to this flash flood warning; the first came 18 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 10.5 hours before the alert went out and 46 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: 69 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 570 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 62 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

591 
WGUS54 KOHX 012227
FFWOHX
TNC119-187-020030-
/O.NEW.KOHX.FF.W.0029.200901T2227Z-200902T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
527 PM CDT Tue Sep 1 2020

The National Weather Service in Nashville has issued a

* Flash Flood Warning for...
  Northeastern Maury County in middle Tennessee...
  Williamson County in middle Tennessee...

* Until 730 PM CDT.

* At 527 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Franklin, Columbia, Brentwood, Spring Hill, Nolensville, 
  Thompson's Station, Fairview, Leipers Fork, Natchez Trace At 
  Highway 96 and Santa Fe.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots.

A Flash Flood Warning means that flooding is imminent or occurring. 
If you are in the warned area move to higher ground immediately. 
Residents living along streams and creeks should take immediate 
precautions to protect life and property.

&&

LAT...LON 3600 8718 3597 8663 3572 8672 3566 8694
      3573 8723

FLASH FLOOD...RADAR INDICATED

$$

Barnwell

3 follow-up statements

084 
WGUS54 KOHX 020012
FFWOHX
TNC187-020200-
/O.EXT.KOHX.FF.W.0029.000000T0000Z-200902T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
712 PM CDT Tue Sep 1 2020

The National Weather Service in Nashville has extended the

* Flash Flood Warning for...
  Central Williamson County in middle Tennessee...

* Until 900 PM CDT.

* At 712 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Franklin, Brentwood, Spring Hill, Nolensville, Thompson's Station, 
  Leipers Fork and Natchez Trace At Highway 96.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots.

A Flash Flood Warning means that flooding is imminent or occurring. 
If you are in the warned area move to higher ground immediately. 
Residents living along streams and creeks should take immediate 
precautions to protect life and property.

&&

LAT...LON 3597 8663 3572 8672 3570 8678 3572 8682
      3573 8685 3576 8694 3578 8693 3578 8694
      3577 8695 3578 8695 3578 8696 3577 8697
      3578 8700 3580 8704 3581 8705 3599 8704

FLASH FLOOD...RADAR INDICATED

$$

Barnwell

085 
WGUS74 KOHX 020012
FFSOHX

Flash Flood Statement
National Weather Service Nashville TN
712 PM CDT Tue Sep 1 2020

TNC119-020022-
/O.CAN.KOHX.FF.W.0029.000000T0000Z-200902T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maury TN-
712 PM CDT Tue Sep 1 2020

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN MAURY COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

LAT...LON 3597 8663 3572 8672 3570 8678 3572 8682
      3573 8685 3576 8694 3578 8693 3578 8694
      3577 8695 3578 8695 3578 8696 3577 8697
      3578 8700 3580 8704 3581 8705 3599 8704

$$

Barnwell

318 
WGUS54 KOHX 020137
FFWOHX
TNC187-020245-
/O.EXT.KOHX.FF.W.0029.000000T0000Z-200902T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
837 PM CDT Tue Sep 1 2020

The National Weather Service in Nashville has extended the

* Flash Flood Warning for...
  Eastern Williamson County in middle Tennessee...

* Until 945 PM CDT.

* At 837 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen earlier this evening. Flash flooding is ongoing and 
  water should begin to recede over the next hour.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Franklin, Brentwood, Spring Hill, Nolensville and Thompson's 
  Station.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots.

A Flash Flood Warning means that flooding is imminent or occurring. 
If you are in the warned area move to higher ground immediately. 
Residents living along streams and creeks should take immediate 
precautions to protect life and property.

&&

LAT...LON 3597 8663 3572 8672 3571 8676 3571 8677
      3570 8677 3570 8678 3572 8682 3576 8694
      3578 8693 3598 8687

FLASH FLOOD...RADAR INDICATED

$$

Barnwell

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Nashville, TN wrote its last area forecast discussion before this flash flood warning went out at Sep 1, 2:42 PM CDT, 2 hours 45 minutes earlier.

Area forecast discussion, Sep 1, 2:42 PM CDT, 2 hours 45 minutes before

Area Forecast Discussion
National Weather Service Nashville TN
242 PM CDT Tue Sep 1 2020

.DISCUSSION...

Current radar trends indicate showers and thunderstorms will move
into the west and southwest portions of the mid-state this
afternoon and evening. Most of the activity is expected to
remain sub-severe with wind gusts to 40mph and heavy rain, but an
isolated severe storm may be possible especially west of the
plateau.

During the overnight hours, short-term models indicate a band of
heavy rain setting up for areas north of I-40. An axis of higher
precipitable water ranging from 2.0 to 2.5 inches, theta-e
advection, southwesterly 850mb winds of 30-35kts, and moisture
transport all peak between 06Z and 14Z. The best time for the
highest rainfall rates look to be between 08Z to 12Z. HRRR
depicts 1 hour rainfall amounts of an inch in some places, and
it's likely rainfall totals of 2 inches or more may be possible
for some localized areas by daybreak. The favored areas are north
of I-40 and west of I-65 between 06Z and 12Z, with areas east of
I-65 being impacted more towards daybreak and into the morning
hours.

GFS shows a repeat for Wednesday night with similar parameters as
above, and even similar time frames. It shows this boundary a
little further south, more along the I-40 corridor. So we'll see
how tonight pans out to get a better handle on the chances for
heavy rain and flash flooding tomorrow night. Having been in a wet
pattern the last several days, soil moisture is high and intense
rainfall will quickly runoff and overwhelm the smaller basins.

This boundary pushes through Friday, followed by cooler and drier
conditions for Saturday and Sunday. Expect highs in the low to mid
80s with overnight lows in the low 60s. Might even see some upper
50s Sunday morning. Enjoy the weekend because low shower and
thunderstorm chances return on Monday and increase for Tuesday.

&&

.AVIATION...
18Z TAF DISCUSSION.

MVFR/VFR CIGs continue this afternoon. A line of TSRA with gusty
winds will approach CKV in the next hour or so, reducing VIS/CIGs.
More TSRA are expected to develop and push toward BNA/MQY and
perhaps CSV this aft/eve. Activity may wane after 01z-02z, with
some CIG improvement at BNA/MQY/CSV. After 06z-09z Wed, more
SHRA/TSRA looks to develop and impact CKV/BNA/MQY. SW winds may
pick up toward the end of the TAF to around 10-15 kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      74  88  73  87  71 /  40  60  40  60  30
Clarksville    73  84  72  84  68 /  70  60  70  60  30
Crossville     70  85  69  83  67 /  10  40  30  60  30
Columbia       73  88  72  88  70 /  30  40  30  50  20
Lawrenceburg   73  88  71  88  69 /   0  30  30  50  20
Waverly        73  85  72  85  69 /  70  70  50  60  30

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

DISCUSSION......05
AVIATION........Schaper

Hazardous weather outlook, Sep 1, 5:06 AM CDT, 12 hours 21 minutes before

Hazardous Weather Outlook
National Weather Service Nashville TN
506 AM CDT Tue Sep 1 2020

TNZ005>011-023>034-056>066-075-077>080-093>095-021015-
Stewart-Montgomery-Robertson-Sumner-Macon-Clay-Pickett-Houston-
Humphreys-Dickson-Cheatham-Davidson-Wilson-Trousdale-Smith-Jackson-
Putnam-Overton-Fentress-Perry-Hickman-Lewis-Williamson-Maury-
Marshall-Rutherford-Cannon-De Kalb-White-Cumberland-Bedford-Coffee-
Warren-Grundy-Van Buren-Wayne-Lawrence-Giles-
506 AM CDT Tue Sep 1 2020

This Hazardous Weather Outlook is for Middle Tennessee.

.DAY ONE...Today and tonight.

Scattered to numerous thunderstorms are expected again today, mainly
during the afternoon. A few of these storms may become strong to
severe, with wind gusts of 40 mph or greater and brief, localized
flooding from heavy rainfall.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed. Please relay any
information about observed severe weather to the NWS while following
all local, state, and CDC guidelines.

08

In the hours before

Special weather statement, Sep 1, 2:36 PM CDT, 2 hours 51 minutes before

Special Weather Statement
National Weather Service Nashville TN
236 PM CDT Tue Sep 1 2020

TNZ024-012015-
Humphreys TN-
236 PM CDT Tue Sep 1 2020

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN HUMPHREYS COUNTY UNTIL
315 PM CDT...

At 235 PM CDT, Doppler radar was tracking a strong thunderstorm near
New Johnsonville, or near Camden, moving east at 25 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Waverly, Camden, New Johnsonville and Hurricane Mills.

This includes Interstate 40 between mile markers 136 and 147.

LAT...LON 3598 8802 3600 8800 3603 8800 3605 8799
      3610 8794 3620 8773 3585 8773 3585 8795
      3587 8794 3594 8793 3594 8800 3596 8802
TIME...MOT...LOC 1935Z 253DEG 22KT 3597 8802

21

Special weather statement, Sep 1, 3:31 PM CDT, 1 hour 56 minutes before

Special Weather Statement
National Weather Service Nashville TN
331 PM CDT Tue Sep 1 2020

TNZ024-025-057-012100-
Hickman TN-Dickson TN-Humphreys TN-
331 PM CDT Tue Sep 1 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN DICKSON...
SOUTHEASTERN HUMPHREYS AND NORTHERN HICKMAN COUNTIES UNTIL 400 PM
CDT...

At 330 PM CDT, Doppler radar was tracking a strong thunderstorm 9
miles east of Hurricane Mills, or 12 miles northwest of Centerville,
moving east at 30 mph.

Winds in excess of 30 mph will be possible with this storm. Frequent
lightning can also be expected.

Locations impacted include...
Dickson, Centerville, Burns, Charlotte, Bon Aqua, Pinewood, Primm
Springs, Lyles, Nunnelly and Bucksnort.

This includes Interstate 40 between mile markers 147 and 174.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3598 8777 3617 8734 3580 8723 3581 8772
      3584 8772 3584 8773
TIME...MOT...LOC 2030Z 254DEG 49KT 3592 8763

21

Special weather statement, Sep 1, 3:36 PM CDT, 1 hour 51 minutes before

Special Weather Statement
National Weather Service Nashville TN
336 PM CDT Tue Sep 1 2020

TNZ094-095-012115-
Lawrence TN-Giles TN-
336 PM CDT Tue Sep 1 2020

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL LAWRENCE AND CENTRAL
GILES COUNTIES UNTIL 415 PM CDT...

At 336 PM CDT, Doppler radar was tracking a strong thunderstorm near
Lawrenceburg, moving northeast at 40 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Lawrenceburg, Pulaski, Loretto, Minor Hill, Ethridge, Goodspring,
Leoma, Westpoint and Frankewing.

This includes Interstate 65 between mile markers 11 and 19.

LAT...LON 3513 8757 3527 8748 3538 8725 3525 8683
      3517 8683 3502 8718
TIME...MOT...LOC 2036Z 247DEG 35KT 3517 8733

21

Special weather statement, Sep 1, 3:59 PM CDT, 1 hour 28 minutes before

Special Weather Statement
National Weather Service Nashville TN
359 PM CDT Tue Sep 1 2020

TNZ025-026-057-059-012145-
Hickman TN-Williamson TN-Dickson TN-Cheatham TN-
359 PM CDT Tue Sep 1 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN DICKSON...
NORTHWESTERN WILLIAMSON...SOUTH CENTRAL CHEATHAM AND NORTHEASTERN
HICKMAN COUNTIES UNTIL 445 PM CDT...

At 359 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles north of Centerville, moving northeast at 30 mph.

Winds in excess of 30 mph will be possible with this storm.

Locations impacted include...
Dickson, Centerville, White Bluff, Kingston Springs, Burns, Fairview,
Bon Aqua, Lyles and Nunnelly.

This includes the following highways...
 Interstate 40 between mile markers 165 and 186.
 Interstate 840 between mile markers 1 and 17.

LAT...LON 3595 8752 3622 8721 3585 8699 3583 8716
      3585 8721 3583 8722 3580 8745
TIME...MOT...LOC 2059Z 243DEG 32KT 3590 8743

21

Special weather statement, Sep 1, 4:51 PM CDT, 36 minutes before

Special Weather Statement
National Weather Service Nashville TN
451 PM CDT Tue Sep 1 2020

TNZ027-059-061-062-012230-
Rutherford TN-Williamson TN-Davidson TN-Marshall TN-
451 PM CDT Tue Sep 1 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN DAVIDSON...
NORTHEASTERN MARSHALL...WESTERN RUTHERFORD AND EASTERN WILLIAMSON
COUNTIES UNTIL 530 PM CDT...

At 451 PM CDT, Doppler radar was tracking a strong thunderstorm 9
miles east of Spring Hill, or 16 miles south of Franklin, moving
northeast at 35 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Murfreesboro, Smyrna, Brentwood, La Vergne, Nolensville, Antioch,
Walterhill, Chapel Hill, Eagleville, Lascassas, Rockvale and Triune.

This includes the following highways...
 Interstate 24 between mile markers 58 and 79.
 Interstate 840 between mile markers 33 and 61.

LAT...LON 3593 8629 3570 8659 3570 8663 3566 8664
      3563 8668 3569 8681 3570 8681 3570 8679
      3571 8678 3571 8681 3572 8682 3573 8684
      3608 8668
TIME...MOT...LOC 2151Z 205DEG 38KT 3571 8675

21

Special weather statement, Sep 1, 5:01 PM CDT, 26 minutes before

Special Weather Statement
National Weather Service Nashville TN
501 PM CDT Tue Sep 1 2020

TNZ027-059-062-012245-
Rutherford TN-Williamson TN-Davidson TN-
501 PM CDT Tue Sep 1 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN DAVIDSON...CENTRAL
RUTHERFORD AND NORTHEASTERN WILLIAMSON COUNTIES UNTIL 545 PM CDT...

At 501 PM CDT, Doppler radar was tracking a strong thunderstorm near
Franklin, moving east at 35 mph.

Wind gusts up to 50 mph will be possible with this storm.

Locations impacted include...
Murfreesboro, Franklin, Smyrna, Brentwood, La Vergne, Nolensville,
Thompson's Station, Walterhill, Antioch and Triune.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3606 8644 3605 8644 3605 8643 3603 8640
      3604 8639 3601 8638 3602 8637 3599 8633
      3579 8635 3580 8688 3601 8690 3610 8652
TIME...MOT...LOC 2201Z 257DEG 31KT 3589 8680

Barnwell

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 1, 1:50 PM CDT	Special Weather Statement	OHX	Stewart	40 min
Sep 1, 2:36 PM CDT	Special Weather Statement	OHX	Humphreys	39 min
Sep 1, 2:49 PM CDT	Severe Thunderstorm Warning	OHX	Hickman, Humphreys	41 min
Sep 1, 3:31 PM CDT	Special Weather Statement	OHX	Dickson	29 min
Sep 1, 3:36 PM CDT	Special Weather Statement	OHX	Giles, Lawrence	39 min
Sep 1, 3:52 PM CDT	Areal Flood Advisory	OHX	Hickman, Humphreys, Perry	3 hr
Sep 1, 3:52 PM CDT	Areal Flood Advisory	OHX	Lawrence	113 min
Sep 1, 3:59 PM CDT	Special Weather Statement	OHX	Dickson	46 min
Sep 1, 4:22 PM CDT	Severe Thunderstorm Warning	OHX	Davidson, Dickson, Hickman, Maury, Williamson	38 min
Sep 1, 4:28 PM CDT	Tornado Warning	OHX	Williamson	32 min
Sep 1, 4:51 PM CDT	Special Weather Statement	OHX	Rutherford	39 min
Sep 1, 4:57 PM CDT	Severe Thunderstorm Warning	OHX	Rutherford, Williamson	33 min
Sep 1, 5:01 PM CDT	Special Weather Statement	OHX	Rutherford	44 min
Sep 1, 5:16 PM CDT	Areal Flood Advisory	OHX	Davidson, Rutherford, Williamson	3 hr
Sep 1, 5:21 PM CDT	Severe Thunderstorm Warning	OHX	Davidson, Rutherford, Wilson	39 min
Sep 1, 5:39 PM CDT	Special Weather Statement	OHX	Wilson	36 min
Sep 1, 5:53 PM CDT	Flash Flood Warning	OHX	Davidson, Rutherford, Williamson	4 hr
Sep 1, 5:59 PM CDT	Severe Thunderstorm Warning	OHX	Macon, Smith, Trousdale, Wilson	46 min
Sep 1, 6:14 PM CDT	Areal Flood Advisory	OHX	Wilson	2 hr

Nearby

Flash Flood Warnings in Tennessee, 2020 Every flash flood warning in 2020

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.