Alert archive / Tennessee / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 101, NWS Morristown, TN

August 9, 2021Scott County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Aug 9, 2021, 5:48 PM EDT for Scott County, Tennessee. It was in force for 42 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
Aug 9, 2021, 5:48 PM EDT (21:48 UTC)
Expired
Aug 9, 2021, 6:30 PM EDT
In force
42 min
Issued by
NWS Morristown, TN
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Scott County, TN

The radar

The Knoxville radar (KMRX), 115 km from the middle of the area, began a volume at 21:49 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 12:00Z, 9.8 hours before the alert went out and 180 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 12:00Z on 2021-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 788 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, Nashville Metro, TN at 12:00Z on 2021-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 square meters per square second.1939Sfc1 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
788 J/kg
Mixed-layer CIN
-39 J/kg
Mixed-layer LCL
892 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
131 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

858 
WUUS54 KMRX 092148
SVRMRX
TNC151-092230-
/O.NEW.KMRX.SV.W.0101.210809T2148Z-210809T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Morristown TN
548 PM EDT Mon Aug 9 2021

The National Weather Service in Morristown has issued a

* Severe Thunderstorm Warning for...
  Northwestern Scott County in east Tennessee...

* Until 630 PM EDT.

* At 547 PM EDT, a severe thunderstorm was located 8 miles west of
  Helenwood, or 12 miles southwest of Oneida, moving east at 15 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...
  Oneida, Huntsville, Helenwood, Honey Creek State Park and Big South
  Fork National Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3660 8450 3641 8444 3637 8469 3639 8469
      3640 8466 3641 8467 3641 8466 3644 8469
      3650 8471 3660 8478
TIME...MOT...LOC 2147Z 248DEG 14KT 3645 8471 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Diegan
2 follow-up statements
098 
WWUS54 KMRX 092217
SVSMRX

Severe Weather Statement
National Weather Service Morristown TN
617 PM EDT Mon Aug 9 2021

TNC151-092230-
/O.CON.KMRX.SV.W.0101.000000T0000Z-210809T2230Z/
Scott TN-
617 PM EDT Mon Aug 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM EDT
FOR NORTH CENTRAL SCOTT COUNTY...

At 616 PM EDT, a severe thunderstorm was located near Oneida, moving
east at 15 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Oneida, Huntsville and Helenwood. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3660 8450 3641 8444 3638 8463 3648 8464
      3660 8470
TIME...MOT...LOC 2216Z 248DEG 14KT 3649 8458 

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

$$

Diegan
013 
WWUS54 KMRX 092226
SVSMRX

Severe Weather Statement
National Weather Service Morristown TN
626 PM EDT Mon Aug 9 2021

TNC151-092236-
/O.EXP.KMRX.SV.W.0101.000000T0000Z-210809T2230Z/
Scott TN-
626 PM EDT Mon Aug 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL SCOTT COUNTY
WILL EXPIRE AT 630 PM EDT...
                
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 will be allowed to expire.

LAT...LON 3660 8450 3641 8444 3638 8463 3648 8464
      3660 8470
TIME...MOT...LOC 2226Z 248DEG 14KT 3650 8454 

$$

Diegan

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 9, 2:24 PM EDTSpecial Weather StatementMRXBradley36 min
Aug 9, 3:17 PM EDTSpecial Weather StatementMRXScott43 min
Aug 9, 5:29 PM EDTSpecial Weather StatementMRXScott46 min
Aug 9, 5:49 PM EDTSevere Thunderstorm WarningMRXMorgan, Scott41 min
Aug 9, 6:07 PM EDTAreal Flood AdvisoryMRXMorgan3 hr
Aug 9, 7:13 PM EDTSpecial Weather StatementMRXAnderson47 min
Aug 9, 7:55 PM EDTSevere Thunderstorm WarningMRXGrainger, Knox, Union39 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.