Alert archive / Tennessee / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 46, NWS Morristown, TN

May 4, 2021Anderson County, Knox County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at May 4, 2021, 4:40 AM EDT for Anderson County, Knox County, Tennessee. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 4, 2021, 4:40 AM EDT (08:40 UTC)
Expired
May 4, 2021, 5:10 AM EDT
In force
30 min
Issued by
NWS Morristown, TN
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Anderson County, TN, Knox County, TN

The radar

The Knoxville radar (KMRX), 77 km from the middle of the area, began a volume at 08:44 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 00:00Z, 8.7 hours before the alert went out and 213 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, Nashville Metro, TN at 00:00Z on 2021-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2263 joules per kilogram.LCLEL10008507005003002001001 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, Nashville Metro, TN at 00:00Z on 2021-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 119 square meters per square second.19395878Sfc1 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
2263 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
1050 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
119 m²/s²
0-3 km storm-relative helicity
193 m²/s²
Significant tornado parameter
1.3
Supercell composite
7.6

Open this sounding in Storm Lab

The text

As transmitted.

895 
WUUS54 KMRX 040840
SVRMRX
TNC001-093-040930-
/O.NEW.KMRX.SV.W.0046.210504T0840Z-210504T0930Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Morristown TN
440 AM EDT Tue May 4 2021

The National Weather Service in Morristown has issued a

* Severe Thunderstorm Warning for...
  Northwestern Knox County in east Tennessee...
  Central Anderson County in east Tennessee...

* Until 530 AM EDT.

* At 440 AM EDT, a severe thunderstorm was located over Oak Ridge,
  moving east at 30 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Knoxville, Oak Ridge, Clinton, Oliver Springs, Norris, Bearden,
  Powell, Karns and Andersonville.

This includes the following highways...
 Interstate 40 in Tennessee between mile markers 376 and 385.
 Interstate 75 in Tennessee between mile markers 110 and 123.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move immediately to shelter inside a strong building. Stay
away from windows.

&&

LAT...LON 3592 8427 3599 8432 3605 8434 3606 8435
      3609 8436 3620 8401 3589 8396
TIME...MOT...LOC 0840Z 261DEG 26KT 3598 8431 

HAIL...1.00IN
WIND...60MPH
 
$$

DGS
1 follow-up statement
156 
WWUS54 KMRX 040910
SVSMRX

Severe Weather Statement
National Weather Service Morristown TN
510 AM EDT Tue May 4 2021

TNC001-093-040920-
/O.CAN.KMRX.SV.W.0046.000000T0000Z-210504T0930Z/
Knox TN-Anderson TN-
510 AM EDT Tue May 4 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN KNOX AND CENTRAL
ANDERSON COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.  However small hail is
still possible with this thunderstorm.

LAT...LON 3592 8427 3599 8432 3605 8434 3606 8435
      3609 8436 3620 8401 3589 8396
TIME...MOT...LOC 0910Z 261DEG 26KT 3601 8404 

$$

DGS

The office that day

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

IssuedProductOfficeCountiesLasted
May 3, 8:29 PM EDTSpecial Weather StatementMRXGreene, Unicoi, Washington46 min
May 3, 8:47 PM EDTSpecial Weather StatementMRXHamblen, Jefferson43 min
May 4, 3:10 AM EDTSevere Thunderstorm WarningMRXMorgan, Roane50 min
May 4, 3:53 AM EDTSevere Thunderstorm WarningMRXAnderson, Morgan, Roane52 min
May 4, 3:56 AM EDTSpecial Weather StatementMRXMorgan49 min
May 4, 4:12 AM EDTSpecial Weather StatementMRXMorgan48 min
May 4, 4:45 AM EDTSpecial Weather StatementMRXBlount45 min
May 4, 4:57 AM EDTAreal Flood AdvisoryMRXAnderson, Morgan, Roane3 hr
May 4, 5:14 AM EDTSpecial Weather StatementMRXKnox46 min
May 4, 5:34 AM EDTSpecial Weather StatementMRXBlount41 min
May 4, 6:05 AM EDTSevere Thunderstorm WarningMRXBlount, Sevier30 min
May 4, 6:11 AM EDTAreal Flood AdvisoryMRXAnderson, Knox3 hr
May 4, 6:16 AM EDTAreal Flood AdvisoryMRXBlount3 hr
May 4, 6:52 AM EDTSpecial Weather StatementMRXSevier53 min
May 4, 7:00 AM EDTFlash Flood WarningMRXBlount, Sevier3 hr
May 4, 7:24 AM EDTAreal Flood AdvisoryMRXScott3 hr
May 4, 7:58 AM EDTSpecial Weather StatementMRXCocke47 min
May 4, 9:05 AM EDTSpecial Weather StatementMRXMorgan, Scott40 min
May 4, 9:18 AM EDTSpecial Weather StatementMRXHamilton27 min
May 4, 9:37 AM EDTSevere Thunderstorm WarningMRXBledsoe, Morgan, Rhea, Roane38 min
May 4, 9:48 AM EDTSevere Thunderstorm WarningMRXBledsoe, Rhea27 min
May 4, 9:50 AM EDTSpecial Weather StatementMRXAnderson, Campbell, Claiborne, Union40 min
May 4, 9:53 AM EDTSpecial Weather StatementMRXHamilton, Marion, Sequatchie67 min
May 4, 10:03 AM EDTSevere Thunderstorm WarningMRXAnderson, Blount, Knox, Loudon, Roane13 min
May 4, 10:18 AM EDTSpecial Weather StatementMRXMcMinn, Meigs57 min
May 4, 10:24 AM EDTSpecial Weather StatementMRXBlount, Knox36 min
May 4, 10:37 AM EDTSpecial Weather StatementMRXHamblen38 min
May 4, 10:41 AM EDTSevere Thunderstorm WarningMRXBlount, Jefferson, Knox, Sevier34 min
May 4, 10:45 AM EDTSevere Thunderstorm WarningMRXBlount, Monroe30 min
May 4, 11:10 AM EDTSevere Thunderstorm WarningMRXCocke, Jefferson, Sevier22 min
May 4, 11:11 AM EDTFlash Flood WarningMRXHamilton, Marion, Sequatchie3 hr
May 4, 11:29 AM EDTAreal Flood WarningMRXBlount, Sevier6 hr
May 4, 11:44 AM EDTAreal Flood AdvisoryMRXBlount, Monroe2 hr
May 4, 11:47 AM EDTAreal Flood AdvisoryMRXBlount, Sevier118 min
May 4, 12:06 PM EDTSpecial Weather StatementMRXPolk24 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.