Alert archive / Tennessee / Flash Flood Warnings in 2020

Flash Flood Warning 21, NWS Nashville, TN

July 20, 2020Sumner County, Wilson County, Tennessee

NWS Nashville, TN issued this flash flood warning at Jul 20, 2020, 6:55 PM CDT for Sumner County, Wilson County, Tennessee. It was in force for 2 hr. 1 report 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: Jul 20, 2020, 6:55 PM CDT (23:55 UTC)
Expired: Jul 20, 2020, 9:00 PM CDT
In force: 2 hr
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Flood severity: None

Counties Sumner County, TN, Wilson County, TN

The radar

The Nashville radar (KOHX), 21 km from the middle of the area, began a volume at 23:58 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
Jul 20, 8:02 PM CDT	FLASH FLOOD	8 Nnw Lebanon, TN	SUNNYMEADE DR NEAR CENTRAL PIKE IS UNDER WATER.

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, 11.9 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-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: 1474 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 1142 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 49 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

595 
WGUS54 KOHX 202355
FFWOHX
TNC165-189-210200-
/O.NEW.KOHX.FF.W.0021.200720T2355Z-200721T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
655 PM CDT Mon Jul 20 2020

The National Weather Service in Nashville has issued a

* Flash Flood Warning for...
  Southeastern Sumner County in middle Tennessee...
  North Central Wilson County in middle Tennessee...

* Until 900 PM CDT.

* At 655 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 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...
  Gallatin, Lebanon and Bledsoe Creek State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3634 8644 3640 8634 3633 8626 3633 8627
      3632 8627 3631 8627 3630 8627 3622 8640
      3631 8649

FLASH FLOOD...RADAR INDICATED

$$

21

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 1:24 PM CDT	Special Weather Statement	OHX	Jackson	36 min
Jul 20, 2:22 PM CDT	Areal Flood Advisory	OHX	Jackson	68 min
Jul 20, 4:24 PM CDT	Special Weather Statement	OHX	Jackson	21 min
Jul 20, 4:39 PM CDT	Areal Flood Advisory	OHX	Jackson	2 hr
Jul 20, 4:55 PM CDT	Special Weather Statement	OHX	Trousdale	50 min
Jul 20, 5:37 PM CDT	Special Weather Statement	OHX	Montgomery	23 min
Jul 20, 5:56 PM CDT	Special Weather Statement	OHX	Trousdale	49 min
Jul 20, 6:02 PM CDT	Special Weather Statement	OHX	Montgomery	28 min
Jul 20, 6:10 PM CDT	Severe Thunderstorm Warning	OHX	Davidson, Sumner, Wilson	35 min
Jul 20, 6:25 PM CDT	Areal Flood Advisory	OHX	Sumner, Wilson	2 hr
Jul 20, 6:41 PM CDT	Severe Thunderstorm Warning	OHX	Sumner, Wilson	34 min

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.