Alert archive / Tennessee / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 71, NWS Morristown, TN

June 21, 2021Grainger County, Jefferson County, Knox County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Jun 21, 2021, 5:36 PM EDT for Grainger County, Jefferson County, Knox County, Tennessee. It was in force for 39 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: Jun 21, 2021, 5:36 PM EDT (21:36 UTC)
Expired: Jun 21, 2021, 6:15 PM EDT
In force: 39 min
Issued by: NWS Morristown, TN
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

Counties Grainger County, TN, Jefferson County, TN, Knox County, TN

The radar

The Knoxville radar (KMRX), 36 km from the middle of the area, began a volume at 21:40 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
Jun 21, 5:51 PM EDT	TSTM WND DMG	2 Ese Halls, TN	A FEW TREES DOWN.

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, 9.6 hours before the alert went out and 255 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: 1530 J/kg
Mixed-layer CIN: -42 J/kg
Mixed-layer LCL: 919 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 211 m²/s²
0-3 km storm-relative helicity: 228 m²/s²
Significant tornado parameter: 1.3
Supercell composite: 9.6

Open this sounding in Storm Lab

The text

As transmitted.

444 
WUUS54 KMRX 212136
SVRMRX
TNC057-089-093-212215-
/O.NEW.KMRX.SV.W.0071.210621T2136Z-210621T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Morristown TN
536 PM EDT Mon Jun 21 2021

The National Weather Service in Morristown has issued a

* Severe Thunderstorm Warning for...
  East central Knox County in east Tennessee...
  Northwestern Jefferson County in east Tennessee...
  Southwestern Grainger County in east Tennessee...

* Until 615 PM EDT.

* At 536 PM EDT, a severe thunderstorm was located near Clinton,
  moving east at 40 mph.

  HAZARD...60 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Knoxville, Jefferson City, New Market, Strawberry Plains, Halls,
  Blaine, Maloneyville, Mascot, Piedmont and Powell.

This includes the following highways...
 Interstate 40 in Tennessee between mile markers 389 and 405, and
between mile markers 410 and 413.
 Interstate 75 in Tennessee between mile markers 108 and 114.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3598 8407 3602 8408 3604 8406 3608 8409
      3610 8373 3617 8362 3619 8356 3619 8349
      3598 8350 3598 8355 3604 8365 3603 8368
      3599 8365 3597 8366 3597 8380
TIME...MOT...LOC 2136Z 263DEG 34KT 3604 8413 

HAIL...0.88IN
WIND...60MPH
 
$$

SR

1 follow-up statement

859 
WWUS54 KMRX 212209
SVSMRX

Severe Weather Statement
National Weather Service Morristown TN
609 PM EDT Mon Jun 21 2021

TNC057-212219-
/O.CAN.KMRX.SV.W.0071.000000T0000Z-210621T2215Z/
Grainger TN-
609 PM EDT Mon Jun 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN GRAINGER COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 3597 8382 3609 8384 3610 8373 3612 8370
      3608 8366 3612 8368 3612 8365 3610 8365
      3610 8363 3612 8363 3614 8364 3614 8362
      3613 8361 3616 8360 3598 8354 3604 8365
      3603 8368 3599 8365 3597 8366
TIME...MOT...LOC 2209Z 256DEG 30KT 3603 8375 

$$

TNC089-093-212215-
/O.CON.KMRX.SV.W.0071.000000T0000Z-210621T2215Z/
Knox TN-Jefferson TN-
609 PM EDT Mon Jun 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR EAST CENTRAL KNOX AND NORTHWESTERN JEFFERSON COUNTIES...

At 609 PM EDT, a severe thunderstorm was located 10 miles south of
Plainview, or 11 miles east of Knoxville, moving east at 35 mph.

HAZARD...60 mph wind gusts and nickel size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Knoxville, Strawberry Plains, Maloneyville and Mascot. 

This includes Interstate 40 in Tennessee between mile markers 395 and
405, and near mile marker 411.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3597 8382 3609 8384 3610 8373 3612 8370
      3608 8366 3612 8368 3612 8365 3610 8365
      3610 8363 3612 8363 3614 8364 3614 8362
      3613 8361 3616 8360 3598 8354 3604 8365
      3603 8368 3599 8365 3597 8366
TIME...MOT...LOC 2209Z 256DEG 30KT 3603 8375 

HAIL...0.88IN
WIND...60MPH
 
$$

Garuckas

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 21, 4:21 PM EDT	Special Weather Statement	MRX	Morgan	39 min
Jun 21, 4:29 PM EDT	Severe Thunderstorm Warning	MRX	Campbell, Morgan	46 min
Jun 21, 4:40 PM EDT	Special Weather Statement	MRX	Grainger	50 min
Jun 21, 4:48 PM EDT	Special Weather Statement	MRX	Union	42 min
Jun 21, 4:55 PM EDT	Severe Thunderstorm Warning	MRX	Anderson, Campbell, Morgan, Roane, Scott	65 min
Jun 21, 5:01 PM EDT	Special Weather Statement	MRX	Claiborne	44 min
Jun 21, 5:05 PM EDT	Severe Thunderstorm Warning	MRX	Campbell, Morgan, Scott	40 min
Jun 21, 5:08 PM EDT	Severe Thunderstorm Warning	MRX	Grainger, Hancock, Hawkins	67 min
Jun 21, 5:12 PM EDT	Severe Thunderstorm Warning	MRX	Campbell, Claiborne, Union	48 min
Jun 21, 5:29 PM EDT	Severe Thunderstorm Warning	MRX	Campbell, Grainger, Knox, Union	46 min
Jun 21, 5:34 PM EDT	Special Weather Statement	MRX	Bradley, Hamilton, Marion, Sequatchie	41 min
Jun 21, 5:42 PM EDT	Severe Thunderstorm Warning	MRX	Campbell, Claiborne	48 min
Jun 21, 5:46 PM EDT	Special Weather Statement	MRX	Loudon	44 min
Jun 21, 5:53 PM EDT	Severe Thunderstorm Warning	MRX	Hancock	41 min
Jun 21, 5:57 PM EDT	Severe Thunderstorm Warning	MRX	Claiborne, Grainger, Hancock	48 min
Jun 21, 6:02 PM EDT	Severe Thunderstorm Warning	MRX	Blount, Loudon, McMinn, Monroe, Roane	43 min
Jun 21, 6:02 PM EDT	Severe Thunderstorm Warning	MRX	Claiborne, Cocke, Grainger, Greene, Hamblen, Hawkins and 1 more	58 min
Jun 21, 6:05 PM EDT	Special Weather Statement	MRX	McMinn	40 min
Jun 21, 6:25 PM EDT	Special Weather Statement	MRX	Bradley, McMinn	65 min
Jun 21, 6:33 PM EDT	Special Weather Statement	MRX	Anderson	57 min
Jun 21, 6:50 PM EDT	Severe Thunderstorm Warning	MRX	Blount, Monroe	40 min
Jun 21, 6:54 PM EDT	Severe Thunderstorm Warning	MRX	Blount, Knox, Sevier	51 min
Jun 21, 7:19 PM EDT	Severe Thunderstorm Warning	MRX	Morgan, Rhea, Roane	56 min
Jun 21, 7:41 PM EDT	Severe Thunderstorm Warning	MRX	Anderson, Blount, Knox, Loudon, Morgan, Roane	49 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 2021 Every 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.