Alert archive / Tennessee / Flash Flood Warnings in 2021

Flash Flood Warning 58, NWS Nashville, TN

August 30, 20215 counties in Tennessee

NWS Nashville, TN issued this flash flood warning at Aug 30, 2021, 5:37 PM CDT for 5 counties in Tennessee. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 30, 2021, 5:37 PM CDT (22:37 UTC)
Expired: Aug 30, 2021, 8:00 PM CDT
In force: 2 hr
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Flood severity: None

Counties Macon County, TN, Smith County, TN, Sumner County, TN, Trousdale County, TN, Wilson County, TN

The radar

The Nashville radar (KOHX), 35 km from the middle of the area, began a volume at 22:38 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, 10.6 hours before the alert went out and 45 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: 437 J/kg
Mixed-layer CIN: -81 J/kg
Mixed-layer LCL: 1082 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 32 m²/s²
0-3 km storm-relative helicity: 17 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

092 
WGUS54 KOHX 302237
FFWOHX
TNC111-159-165-169-189-310100-
/O.NEW.KOHX.FF.W.0058.210830T2237Z-210831T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
537 PM CDT Mon Aug 30 2021

The National Weather Service in Nashville has issued a

* Flash Flood Warning for...
  Southwestern Macon County in middle Tennessee...
  Northwestern Smith County in middle Tennessee...
  Southeastern Sumner County in middle Tennessee...
  Trousdale County in middle Tennessee...
  Northeastern Wilson County in middle Tennessee...

* Until 800 PM CDT.

* At 537 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2.5 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...
  Gallatin, Lafayette, Hartsville, Dickerson Chapel Recreation Area, 
  Dixon Springs, Bethpage and Bledsoe Creek State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move to higher ground now. Act quickly to protect your life.

&&

LAT...LON 3637 8644 3648 8635 3651 8624 3655 8611
      3653 8598 3632 8599 3633 8609 3625 8614
      3630 8626 3631 8630

FLASH FLOOD...RADAR INDICATED

$$

Schaper

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 30, 2:39 PM CDT	Special Weather Statement	OHX	Bedford	51 min
Aug 30, 3:33 PM CDT	Areal Flood Advisory	OHX	Clay, Fentress, Pickett	117 min
Aug 30, 3:43 PM CDT	Special Weather Statement	OHX	Davidson	32 min
Aug 30, 3:52 PM CDT	Special Weather Statement	OHX	Giles	38 min
Aug 30, 4:09 PM CDT	Special Weather Statement	OHX	Trousdale	36 min
Aug 30, 4:15 PM CDT	Special Weather Statement	OHX	Davidson, Wilson	45 min
Aug 30, 4:42 PM CDT	Areal Flood Advisory	OHX	Davidson, Rutherford, Wilson	78 min
Aug 30, 4:58 PM CDT	Special Weather Statement	OHX	Sumner	47 min
Aug 30, 5:01 PM CDT	Areal Flood Advisory	OHX	Macon, Smith, Trousdale	59 min
Aug 30, 5:22 PM CDT	Areal Flood Advisory	OHX	Davidson, Robertson, Sumner, Trousdale, Wilson	2 hr
Aug 30, 5:33 PM CDT	Areal Flood Advisory	OHX	Clay, Macon	57 min
Aug 30, 5:49 PM CDT	Areal Flood Advisory	OHX	DeKalb, Putnam, Smith, White	71 min
Aug 30, 5:55 PM CDT	Areal Flood Advisory	OHX	Macon, Robertson, Sumner	2 hr
Aug 30, 6:20 PM CDT	Areal Flood Advisory	OHX	Clay, Jackson, Macon, Overton, Putnam, Smith and 1 more	100 min
Aug 30, 6:49 PM CDT	Special Weather Statement	OHX	Jackson	41 min

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.