Alert archive / Tennessee / Flash Flood Warnings in 2021

Flash Flood Warning 40, NWS Nashville, TN

July 20, 2021Wayne County, Tennessee

NWS Nashville, TN issued this flash flood warning at Jul 20, 2021, 6:49 PM CDT for Wayne County, Tennessee. It was in force for 116 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 20, 2021, 6:49 PM CDT (23:49 UTC)
Expired: Jul 20, 2021, 8:45 PM CDT
In force: 116 min
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Flood severity: None

County Wayne County, TN

The radar

The Columbus AFB radar (KGWX), 161 km from the middle of the area, began a volume at 23:51 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 12:00Z, 11.8 hours before the alert went out and 152 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: 133 J/kg
Mixed-layer CIN: -72 J/kg
Mixed-layer LCL: 925 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: -26 m²/s²
0-3 km storm-relative helicity: -27 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

624 
WGUS54 KOHX 202349
FFWOHX
TNC181-210145-
/O.NEW.KOHX.FF.W.0040.210720T2349Z-210721T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
649 PM CDT Tue Jul 20 2021

The National Weather Service in Nashville has issued a

* Flash Flood Warning for...
  West Central Wayne County in middle Tennessee...

* Until 845 PM CDT.

* At 649 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2 inches of 
  rain have fallen. 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...
  Waynesboro.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3532 8802 3538 8794 3538 8780 3534 8772
      3527 8785 3522 8798 3530 8798 3530 8799
      3530 8800 3530 8802 3531 8802 3531 8801

FLASH FLOOD...RADAR INDICATED

$$

Whitehead

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 10:13 PM CDT	Areal Flood Advisory	OHX	Hickman, Humphreys, Perry	2 hr
Jul 19, 10:41 PM CDT	Flash Flood Warning	OHX	Humphreys, Perry	2 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.