Alert archive / Tennessee / Tornado Warnings in 2011

Tornado Warning 46, NWS Nashville, TN

April 20, 2011Macon County, Robertson County, Sumner County, Tennessee

NWS Nashville, TN issued this tornado warning at Apr 20, 2011, 1:32 AM CDT for Macon County, Robertson County, Sumner County, Tennessee. It was in force for 18 min. 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: Apr 20, 2011, 1:32 AM CDT (06:32 UTC)
Expired: Apr 20, 2011, 1:50 AM CDT
In force: 18 min
Issued by: NWS Nashville, TN
Area: Storm-based polygon

Counties Macon County, TN, Robertson County, TN, Sumner County, TN

The radar

The Nashville radar (KOHX), 45 km from the middle of the area, began a volume at 06:33 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
Apr 20, 1:42 AM CDT	HAIL 1	Portland, TN	1 INCH HAIL REPORTED IN PORTLAND.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 19, 10:14 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 6.5 hours before the alert went out and 58 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: 1997 J/kg
Mixed-layer CIN: -93 J/kg
Mixed-layer LCL: 1626 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 92 m²/s²
0-3 km storm-relative helicity: 239 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 7.7

Open this sounding in Storm Lab

The text

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

313 
WFUS54 KOHX 200632
TOROHX
TNC111-147-165-200700-
/O.NEW.KOHX.TO.W.0046.110420T0632Z-110420T0700Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NASHVILLE TN
132 AM CDT WED APR 20 2011

THE NATIONAL WEATHER SERVICE IN NASHVILLE HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHERN MACON COUNTY IN MIDDLE TENNESSEE...
  NORTHEASTERN ROBERTSON COUNTY IN MIDDLE TENNESSEE...
  NORTHERN SUMNER COUNTY IN MIDDLE TENNESSEE...

* UNTIL 200 AM CDT

* AT 128 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS           
  DANGEROUS STORM WAS LOCATED NEAR CROSS PLAINS...MOVING EAST AT 50  
  MPH.

* LOCATIONS IMPACTED INCLUDE...
  LAFAYETTE...PORTLAND...WESTMORELAND AND MITCHELLVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3663 8579 3653 8580 3648 8674 3666 8676
      3666 8671 3666 8659 3665 8657 3666 8654
      3666 8642
TIME...MOT...LOC 0632Z 263DEG 45KT 3658 8662

$$

JLM

1 follow-up statement

102 
WWUS54 KOHX 200650
SVSOHX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
150 AM CDT WED APR 20 2011

TNC111-147-165-200700-
/O.CAN.KOHX.TO.W.0046.000000T0000Z-110420T0700Z/
MACON TN-ROBERTSON TN-SUMNER TN-
150 AM CDT WED APR 20 2011

...THE TORNADO WARNING FOR NORTHERN SUMNER...NORTHEASTERN ROBERTSON
AND NORTHERN MACON COUNTIES IS CANCELLED...

THE TORNADO THREAT HAS DIMINISHED...THEREFORE THE TORNADO WARNING HAS
BEEN CANCELLED. HOWEVER...A SEVERE THUNDERSTORM WARNING REMAINS IN
EFFECT FOR THE AREA.

ADDITIONAL STRONG THUNDERSTORMS ARE STILL POSSIBLE...AND A TORNADO 
WATCH REMAINS IN EFFECT UNTIL 5 AM.

LAT...LON 3663 8579 3653 8580 3648 8674 3666 8676
      3666 8671 3666 8659 3665 8657 3666 8654
      3666 8642
TIME...MOT...LOC 0650Z 263DEG 45KT 3660 8634

$$

JLM

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 20, 12:03 AM CDT	Severe Thunderstorm Warning	OHX	Benton, Dickson, Hickman, Houston, Humphreys, Lewis and 3 more	42 min
Apr 20, 12:21 AM CDT	Tornado Warning	OHX	Stewart	24 min
Apr 20, 12:44 AM CDT	Tornado Warning	OHX	Montgomery, Stewart	31 min
Apr 20, 12:46 AM CDT	Severe Thunderstorm Warning	OHX	Cheatham, Davidson, Dickson, Hickman, Houston, Humphreys and 4 more	44 min
Apr 20, 12:49 AM CDT	Severe Thunderstorm Warning	OHX	Cheatham, Davidson, Dickson, Giles, Hickman, Lawrence and 7 more	41 min
Apr 20, 1:07 AM CDT	Tornado Warning	OHX	Montgomery, Robertson	23 min
Apr 20, 1:28 AM CDT	Severe Thunderstorm Warning	OHX	Davidson, Jackson, Macon, Robertson, Smith, Sumner and 2 more	47 min
Apr 20, 1:30 AM CDT	Severe Thunderstorm Warning	OHX	Bedford, Cannon, Davidson, DeKalb, Giles, Lawrence and 7 more	45 min
Apr 20, 2:09 AM CDT	Severe Thunderstorm Warning	OHX	Clay, Cumberland, DeKalb, Fentress, Jackson, Macon and 7 more	36 min
Apr 20, 2:11 AM CDT	Severe Thunderstorm Warning	OHX	Bedford, Cannon, Coffee, Cumberland, DeKalb, Giles and 8 more	64 min
Apr 20, 3:11 AM CDT	Severe Thunderstorm Warning	OHX	Coffee, Cumberland, Fentress, Grundy, Overton, Putnam and 3 more	49 min
Apr 20, 3:56 AM CDT	Severe Thunderstorm Warning	OHX	Lawrence, Lewis, Marshall	34 min
Apr 20, 3:57 AM CDT	Severe Thunderstorm Warning	OHX	Lawrence, Lewis	33 min
Apr 20, 4:05 AM CDT	Severe Thunderstorm Warning	OHX	Giles, Lawrence, Lewis, Maury, Wayne	25 min
Apr 20, 4:12 AM CDT	Areal Flood Advisory	OHX	Lawrence, Lewis, Perry, Wayne	2 hr
Apr 20, 5:58 AM CDT	Severe Thunderstorm Warning	OHX	Giles, Lawrence, Lewis, Maury	22 min
Apr 20, 9:11 AM CDT	River Flood Advisory	OHX	Decatur, Hardin, Perry, Wayne	6 days
Apr 20, 5:32 PM CDT	Severe Thunderstorm Warning	OHX	Wayne	28 min
Apr 20, 5:56 PM CDT	Severe Thunderstorm Warning	OHX	Wayne	19 min
Apr 20, 6:09 PM CDT	Severe Thunderstorm Warning	OHX	Lawrence, Lewis	36 min

Nearby

Tornado Warnings in Tennessee, 2011 Every tornado warning in 2011 Tornadoes in 2011

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.