Alert archive / Tennessee / Flash Flood Warnings in 2012

Flash Flood Warning 20, NWS Nashville, TN

September 17, 2012Giles County, Marshall County, Tennessee

NWS Nashville, TN issued this flash flood warning at Sep 17, 2012, 2:11 PM CDT for Giles County, Marshall County, Tennessee. It was in force for 3 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: Sep 17, 2012, 2:11 PM CDT (19:11 UTC)
Expired: Sep 17, 2012, 5:00 PM CDT
In force: 3 hr
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Flood severity: None

Counties Giles County, TN, Marshall County, TN

The radar

The Northeast Alabama radar (KHTX), 89 km from the middle of the area, began a volume at 19:11 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, 7.2 hours before the alert went out and 93 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: 491 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 510 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 38 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

619 
WGUS54 KOHX 171911
FFWOHX
TNC055-117-172200-
/O.NEW.KOHX.FF.W.0020.120917T1911Z-120917T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NASHVILLE TN
211 PM CDT MON SEP 17 2012

THE NATIONAL WEATHER SERVICE IN NASHVILLE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  GILES COUNTY IN MIDDLE TENNESSEE...
  MARSHALL COUNTY IN MIDDLE TENNESSEE...

* UNTIL 500 PM CDT

* AT 209 PM CDT...DOPPLER RADAR INDICATED AN AREA OF HEAVY RAINFALL  
  IS IMPACTING GILES AND MARSHALL COUNTIES. THESE AREAS HAVE ALREADY 
  SEEN HEAVY RAINS THIS MORNING AND THE SATURATED SOILS COUPLED WITH 
  THE NEXT ROUND OF HEAVY RAIN COULD PRODUCE FLASH FLOODING.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...LEWISBURG
  AND PULASKI.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...
COUNTRY ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND
OTHER LOW LYING AREAS ARE SUBJECT TO FLOODING.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
NASHVILLE.

&&

LAT...LON 3501 8722 3512 8722 3513 8720 3543 8720
      3545 8710 3541 8701 3541 8696 3552 8685
      3570 8679 3569 8664 3559 8666 3545 8667
      3536 8661 3526 8675 3526 8683 3500 8684

$$

TB12

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 17, 2:48 AM CDT	Flood Watch	OHX	Bedford, Cannon, Clay, Coffee, Cumberland, Davidson and 23 more	27 hr
Sep 17, 11:41 AM CDT	Areal Flood Advisory	OHX	Giles, Hickman, Lawrence, Lewis, Marshall, Maury and 1 more	6 hr
Sep 17, 1:46 PM CDT	Tornado Warning	OHX	Bedford	29 min
Sep 17, 2:55 PM CDT	Areal Flood Advisory	OHX	Bedford, Rutherford, Williamson	6 hr
Sep 17, 3:55 PM CDT	Tornado Warning	OHX	Bedford	35 min
Sep 17, 3:56 PM CDT	Tornado Warning	OHX	Cannon, Coffee, Warren	34 min
Sep 17, 3:57 PM CDT	Tornado Warning	OHX	Van Buren, Warren, White	33 min
Sep 17, 4:06 PM CDT	Tornado Warning	OHX	Coffee	54 min
Sep 17, 4:26 PM CDT	Tornado Warning	OHX	DeKalb, Warren, White	34 min
Sep 17, 4:28 PM CDT	Tornado Warning	OHX	Van Buren, Warren, White	32 min
Sep 17, 4:43 PM CDT	Tornado Warning	OHX	Cannon, Warren	47 min
Sep 17, 6:15 PM CDT	Areal Flood Advisory	OHX	Cannon, Coffee, DeKalb, Jackson, Overton, Putnam and 2 more	4 hr

Nearby

Flash Flood Warnings in Tennessee, 2012 Every flash flood warning in 2012

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.