Alert archive / Tennessee / Flash Flood Warnings in 2021

Flash Flood Warning 35, NWS Nashville, TN

July 17, 2021Lawrence County, Tennessee

NWS Nashville, TN issued this flash flood warning at Jul 17, 2021, 9:03 PM CDT for Lawrence County, Tennessee. It was in force for 117 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 17, 2021, 9:03 PM CDT (02:03 UTC)
Expired: Jul 17, 2021, 11:00 PM CDT
In force: 117 min
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Flood severity: None

County Lawrence County, TN

The radar

The Northeast Alabama radar (KHTX), 136 km from the middle of the area, began a volume at 02:02 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, 2.1 hours before the alert went out and 144 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: 1153 J/kg
Mixed-layer CIN: -12 J/kg
Mixed-layer LCL: 894 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 81 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

237 
WGUS54 KOHX 180203
FFWOHX
TNC099-180400-
/O.NEW.KOHX.FF.W.0035.210718T0203Z-210718T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
903 PM CDT Sat Jul 17 2021

The National Weather Service in Nashville has issued a

* Flash Flood Warning for...
  Southwestern Lawrence County in middle Tennessee...

* Until 1100 PM CDT.

* At 903 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 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...
  Loretto, St. Joseph, Westpoint and Iron City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3515 8758 3517 8757 3519 8757 3519 8758
      3520 8758 3518 8735 3500 8747 3500 8761
      3502 8761 3504 8761 3503 8758 3505 8758
      3506 8758 3506 8759 3514 8759 3514 8758

FLASH FLOOD...RADAR INDICATED

$$

Barnwell

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 7:16 PM CDT	Areal Flood Advisory	OHX	Wilson	119 min
Jul 17, 7:38 PM CDT	Areal Flood Advisory	OHX	Lawrence	112 min
Jul 17, 8:00 PM CDT	Flash Flood Warning	OHX	Lawrence	3 hr
Jul 17, 8:40 PM CDT	Areal Flood Advisory	OHX	Lawrence, Wayne	3 hr
Jul 17, 9:07 PM CDT	Areal Flood Advisory	OHX	Montgomery, Robertson, Sumner	113 min
Jul 17, 10:09 PM CDT	Areal Flood Advisory	OHX	Davidson, Sumner, Trousdale, Wilson	2 hr
Jul 17, 11:19 PM CDT	Areal Flood Advisory	OHX	Smith, Trousdale	116 min
Jul 18, 3:54 PM CDT	Special Weather Statement	OHX	Davidson	51 min
Jul 18, 4:03 PM CDT	Areal Flood Advisory	OHX	Davidson, Williamson	117 min
Jul 18, 4:27 PM CDT	Areal Flood Advisory	OHX	Davidson, Rutherford, Williamson, Wilson	2 hr
Jul 18, 4:31 PM CDT	Flash Flood Warning	OHX	Davidson	89 min
Jul 18, 4:42 PM CDT	Areal Flood Advisory	OHX	Cumberland	3 hr
Jul 18, 6:08 PM CDT	Areal Flood Advisory	OHX	Giles	112 min
Jul 18, 6:11 PM CDT	Areal Flood Advisory	OHX	DeKalb	2 hr
Jul 18, 6:14 PM CDT	Areal Flood Advisory	OHX	Sumner, Wilson	2 hr
Jul 18, 6:17 PM CDT	Areal Flood Advisory	OHX	Perry	118 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.