Alert archive / Tennessee / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 152, NWS Morristown, TN

December 11, 20215 counties in Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Dec 11, 2021, 9:51 AM EST for 5 counties in Tennessee. It was in force for 39 min. 4 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
Dec 11, 2021, 9:51 AM EST (14:51 UTC)
Expired
Dec 11, 2021, 10:30 AM EST
In force
39 min
Issued by
NWS Morristown, TN
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Anderson County, TN, Blount County, TN, Knox County, TN, Loudon County, TN, Roane County, TN

The radar

The Knoxville radar (KMRX), 87 km from the middle of the area, began a volume at 14:55 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

TimeReportWhereRemark
Dec 11, 10:05 AM ESTTSTM WND DMG2 Nne Farragut, TN*** 1 INJ *** TREE DOWN OFF CAMPBELL STATION ROAD.
Dec 11, 10:20 AM ESTTSTM WND DMGKarns, TNOVER 20 TREES DOWN IN THE KARNS COMMUNITY. 1 OF THE DOWNED TREES FELL ON A HOME.
Dec 11, 10:25 AM ESTTSTM WND DMGHalls, TNSEVERAL TREES DOWN.
Dec 11, 10:35 AM ESTNON-TSTM WND GST 622 N Alcoa, TNASOS STATION KTYS KNOXVILLE MCGHEE TYSON.

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

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 2.9 hours before the alert went out and 288 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-pSkew-T log-p diagram, Peachtre/Fal Fld, GA at 12:00Z on 2021-12-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 182 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Peachtre/Fal Fld, GA at 12:00Z on 2021-12-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 268 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
182 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
625 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
268 m²/s²
0-3 km storm-relative helicity
271 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.8

Open this sounding in Storm Lab

The text

As transmitted.

542 
WUUS54 KMRX 111451
SVRMRX
TNC001-009-093-105-145-111530-
/O.NEW.KMRX.SV.W.0152.211211T1451Z-211211T1530Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Morristown TN
951 AM EST Sat Dec 11 2021

The National Weather Service in Morristown has issued a

* Severe Thunderstorm Warning for...
  Loudon County in east Tennessee...
  Western Knox County in east Tennessee...
  Southern Anderson County in east Tennessee...
  Northwestern Blount County in east Tennessee...
  Roane County in east Tennessee...

* Until 1030 AM EST.

* At 950 AM EST, severe thunderstorms were located along a line
  extending from near Kingston to near Fairview, moving east at 55
  mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Knoxville, Oak Ridge, Maryville, Clinton, Lenoir City, Alcoa,
  Kingston, Loudon, Farragut and Fairview.

This includes the following highways...
 Interstate 40 in Tennessee between mile markers 347 and 386.
 Interstate 75 in Tennessee between mile markers 70 and 119.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a DANGEROUS SITUATION. These storms are producing widespread 
wind damage. SEEK SHELTER NOW inside a sturdy structure and stay 
away from windows! 

A Tornado Watch remains in effect until noon EST for east Tennessee.

&&

LAT...LON 3570 8459 3595 8461 3595 8456 3597 8455
      3598 8449 3599 8444 3603 8438 3618 8394
      3617 8391 3617 8390 3571 8400
TIME...MOT...LOC 1450Z 254DEG 46KT 3594 8447 3571 8455 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

DGS
2 follow-up statements
304 
WWUS54 KMRX 111511
SVSMRX

Severe Weather Statement
National Weather Service Morristown TN
1011 AM EST Sat Dec 11 2021

TNC145-111520-
/O.CAN.KMRX.SV.W.0152.000000T0000Z-211211T1530Z/
Roane TN-
1011 AM EST Sat Dec 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR ROANE COUNTY IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 3589 8432 3588 8428 3590 8428 3590 8426
      3604 8434 3618 8394 3617 8391 3617 8390
      3571 8400 3570 8438
TIME...MOT...LOC 1510Z 254DEG 46KT 3601 8418 3578 8426 

$$

TNC001-009-093-105-111530-
/O.CON.KMRX.SV.W.0152.000000T0000Z-211211T1530Z/
Loudon TN-Knox TN-Anderson TN-Blount TN-
1011 AM EST Sat Dec 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1030 AM EST
FOR NORTHEASTERN LOUDON...WESTERN KNOX...SOUTHERN ANDERSON AND
NORTHWESTERN BLOUNT COUNTIES...

At 1010 AM EST, severe thunderstorms were located along a line
extending from 6 miles northeast of Oak Ridge to near Lenoir City,
moving east at 55 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Knoxville, Oak Ridge, Maryville, Clinton, Lenoir City, Alcoa, Loudon,
Farragut, Oliver Springs and Louisville.

This includes the following highways...
 Interstate 40 in Tennessee between mile markers 364 and 386.
 Interstate 75 in Tennessee between mile markers 76 and 119.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

&&

LAT...LON 3589 8432 3588 8428 3590 8428 3590 8426
      3604 8434 3618 8394 3617 8391 3617 8390
      3571 8400 3570 8438
TIME...MOT...LOC 1510Z 254DEG 46KT 3601 8418 3578 8426 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

DGS
235 
WWUS54 KMRX 111524
SVSMRX

Severe Weather Statement
National Weather Service Morristown TN
1024 AM EST Sat Dec 11 2021

TNC001-009-093-105-111533-
/O.EXP.KMRX.SV.W.0152.000000T0000Z-211211T1530Z/
Loudon TN-Knox TN-Anderson TN-Blount TN-
1024 AM EST Sat Dec 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN LOUDON...WESTERN
KNOX...SOUTHERN ANDERSON AND NORTHWESTERN BLOUNT COUNTIES WILL EXPIRE
AT 1030 AM EST...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.

LAT...LON 3589 8432 3588 8428 3590 8428 3590 8426
      3604 8434 3618 8394 3617 8391 3617 8390
      3571 8400 3570 8438
TIME...MOT...LOC 1523Z 254DEG 46KT 3606 8398 3583 8407 

$$

DGS

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 11, 5:57 AM ESTSevere Thunderstorm WarningMRXCampbell, Scott48 min
Dec 11, 6:39 AM ESTSevere Thunderstorm WarningMRXCampbell, Scott51 min
Dec 11, 7:29 AM ESTSevere Thunderstorm WarningMRXCampbell, Scott46 min
Dec 11, 7:43 AM ESTFlash Flood WarningMRXScott4 hr
Dec 11, 7:51 AM ESTSpecial Weather StatementMRXCampbell, Morgan54 min
Dec 11, 8:23 AM ESTSevere Thunderstorm WarningMRXMarion, Sequatchie52 min
Dec 11, 8:23 AM ESTSevere Thunderstorm WarningMRXCampbell, Claiborne, Scott37 min
Dec 11, 9:02 AM ESTSevere Thunderstorm WarningMRXBledsoe, Bradley, Hamilton, McMinn, Meigs, Rhea and 1 more43 min
Dec 11, 9:18 AM ESTSpecial Weather StatementMRXHamilton42 min
Dec 11, 9:18 AM ESTSevere Thunderstorm WarningMRXBledsoe, Meigs, Rhea, Roane42 min
Dec 11, 9:34 AM ESTSevere Thunderstorm WarningMRXBradley, Hamilton, Marion41 min
Dec 11, 9:44 AM ESTSevere Thunderstorm WarningMRXBradley, Loudon, McMinn, Meigs, Monroe, Roane46 min
Dec 11, 10:15 AM ESTSevere Thunderstorm WarningMRXBradley, McMinn, Monroe, Polk45 min
Dec 11, 10:21 AM ESTSevere Thunderstorm WarningMRXBlount, Grainger, Jefferson, Knox, Sevier39 min
Dec 11, 10:25 AM ESTSevere Thunderstorm WarningMRXBlount, Loudon, McMinn, Monroe50 min
Dec 11, 10:30 AM ESTSpecial Weather StatementMRXBradley45 min
Dec 11, 10:53 AM ESTSevere Thunderstorm WarningMRXCocke, Grainger, Greene, Hamblen, Hawkins, Jefferson35 min
Dec 11, 10:59 AM ESTSpecial Weather StatementMRXPolk46 min
Dec 11, 10:59 AM ESTSevere Thunderstorm WarningMRXBlount, Cocke, Jefferson, Sevier30 min
Dec 11, 11:28 AM ESTSpecial Weather StatementMRXSullivan47 min
Dec 11, 11:49 AM ESTSpecial Weather StatementMRXCarter, Johnson, Washington41 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 2021Every severe thunderstorm 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.