Alert archive / Tennessee / Flash Flood Warnings in 2017

Flash Flood Warning 25, NWS Nashville, TN

August 11, 2017Marshall County, Tennessee

NWS Nashville, TN issued this flash flood warning at Aug 11, 2017, 3:20 PM CDT for Marshall County, Tennessee. It was in force for 3 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: Aug 11, 2017, 3:20 PM CDT (20:20 UTC)
Expired: Aug 11, 2017, 6:15 PM CDT
In force: 3 hr
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Flood severity: None

County Marshall County, TN

The radar

The Northeast Alabama radar (KHTX), 88 km from the middle of the area, began a volume at 20:19 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
Aug 11, 4:05 PM CDT	FLASH FLOOD	1 W Lewisburg, TN	SUCCESFUL WATER RESCUES OF PEOPLE IN CARS AROUND OLD COLUMBIA ROAD AT SILVER CREEK... HOPKINS AVE... AND FRANKLIN AVENUE

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, 8.3 hours before the alert went out and 78 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: 732 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 766 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 105 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

810 
WGUS54 KOHX 112020
FFWOHX
TNC117-112315-
/O.NEW.KOHX.FF.W.0025.170811T2020Z-170811T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
320 PM CDT FRI AUG 11 2017

The National Weather Service in Nashville has issued a

* Flash Flood Warning for...
  Central Marshall County in Middle Tennessee...

* Until 615 PM CDT

* At 320 PM CDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Flash flooding is expected to
  begin shortly.

* Some locations that will experience flooding include...
  Lewisburg, Farmington and Belfast. 

LAT...LON 3539 8693 3541 8692 3541 8694 3546 8692
      3547 8692 3549 8688 3552 8688 3550 8687
      3552 8686 3550 8666 3546 8667 3546 8666
      3543 8666 3540 8664 3537 8663

$$

21

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 9:43 PM CDT	Special Weather Statement	OHX	Lawrence	32 min
Aug 10, 10:14 PM CDT	Areal Flood Advisory	OHX	Lawrence, Wayne	2 hr
Aug 10, 11:21 PM CDT	Areal Flood Advisory	OHX	Giles, Lawrence	114 min
Aug 11, 1:47 PM CDT	Areal Flood Advisory	OHX	Marshall	118 min
Aug 11, 2:59 PM CDT	Areal Flood Advisory	OHX	Marshall, Maury	2 hr
Aug 11, 5:33 PM CDT	Special Weather Statement	OHX	Giles, Lawrence	57 min
Aug 11, 6:05 PM CDT	Areal Flood Warning	OHX	Giles	3 hr

Nearby

Flash Flood Warnings in Tennessee, 2017 Every flash flood warning in 2017

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.