Alert archive / Tennessee / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 21, NWS Morristown, TN

February 29, 20126 counties in Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Feb 29, 2012, 5:20 PM CST for 6 counties in Tennessee. It was in force for 40 min. 2 reports 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: Feb 29, 2012, 5:20 PM CST (23:20 UTC)
Expired: Feb 29, 2012, 6:00 PM CST
In force: 40 min
Issued by: NWS Morristown, TN
Area: Storm-based polygon

Counties Bledsoe County, TN, Bradley County, TN, Hamilton County, TN, Meigs County, TN, Rhea County, TN, Sequatchie County, TN

The radar

The Northeast Alabama radar (KHTX), 93 km from the middle of the area, began a volume at 23:22 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
Feb 29, 5:50 PM CST	TSTM WND DMG	Dayton, TN	SEVERAL TREES DOWN.
Feb 29, 5:50 PM CST	HAIL 1	Dayton, TN

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
Feb 29, 11:31 AM CST	Tornado Watch	SPC	8 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 11.3 hours before the alert went out and 150 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: 580 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 510 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: 365 m²/s²
0-3 km storm-relative helicity: 485 m²/s²
Significant tornado parameter: 1.9
Supercell composite: 8.5

Open this sounding in Storm Lab

The text

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

093 
WUUS54 KMRX 292320
SVRMRX
TNC007-011-065-121-143-153-010000-
/O.NEW.KMRX.SV.W.0021.120229T2320Z-120301T0000Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE KNOXVILLE-TRI CITIES TN
ISSUED BY NATIONAL WEATHER SERVICE PEACHTREE CITY GA
620 PM EST WED FEB 29 2012

THE NATIONAL WEATHER SERVICE IN KNOXVILLE-TRI CITIES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN BLEDSOE COUNTY IN TENNESSEE
  NORTH CENTRAL BRADLEY COUNTY IN TENNESSEE
  NORTHERN HAMILTON COUNTY IN TENNESSEE
  CENTRAL MEIGS COUNTY IN TENNESSEE
  RHEA COUNTY IN TENNESSEE
  SEQUATCHIE COUNTY IN TENNESSEE

* UNTIL 700 PM EST/600 PM CST/

* AT 517 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DESTRUCTIVE WINDS UP TO 70
  MPH.  THIS STORM WAS LOCATED 14 MILES WEST OF DUNLAP...MOVING EAST
  AT 70 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  SODDY-DAISY...DAYTON...SPRING CITY AND DECATUR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED ROTATION WITHIN THIS STORM. ALTHOUGH
CURRENT DATA DOES NOT INDICATE THE EXISTENCE OF A TORNADO...A TORNADO
MAY STILL DEVELOP. IF A TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO
A PLACE OF SAFETY INSIDE A STURDY STRUCTURE...SUCH AS A BASEMENT OR
SMALL INTERIOR ROOM.

IF YOU SEE WIND DAMAGE...LARGE HAIL OR SIGNIFICANT FLOODING...WAIT
UNTIL THE STORM HAS PASSED...AND THEN CALL THE NATIONAL WEATHER
SERVICE TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6.

&&

LAT...LON 3525 8543 3528 8545 3532 8556 3534 8556
      3539 8550 3542 8550 3544 8555 3549 8554
      3574 8476 3546 8477 3543 8482 3536 8485
      3532 8478 3524 8479
TIME...MOT...LOC 2320Z 263DEG 60KT 3536 8557

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 29, 4:17 PM CST	Severe Thunderstorm Warning	MRX	Anderson, Campbell	58 min
Feb 29, 4:36 PM CST	Tornado Warning	MRX	Anderson, Campbell, Morgan, Scott	39 min
Feb 29, 4:37 PM CST	Tornado Warning	MRX	Anderson, Campbell, Morgan, Scott	38 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 2012 Every severe thunderstorm 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.