Alert archive / Tennessee / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 277, NWS Morristown, TN

August 4, 2009Claiborne County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Aug 4, 2009, 2:59 PM EDT for Claiborne County, Tennessee. It was in force for 61 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 4, 2009, 2:59 PM EDT (18:59 UTC)
Expired
Aug 4, 2009, 4:00 PM EDT
In force
61 min
Issued by
NWS Morristown, TN
Area
Storm-based polygon

County Claiborne County, TN

The radar

The Knoxville radar (KMRX), 42 km from the middle of the area, began a volume at 19:02 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, 7.0 hours before the alert went out and 266 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 2009-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3443 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 2009-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 80 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
3443 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
680 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
80 m²/s²
0-3 km storm-relative helicity
42 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.8

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Morristown, TN wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 4, 1:30 PM EDT, 1 hour 29 minutes earlier.

Area forecast discussion, Aug 4, 1:30 PM EDT, 1 hour 29 minutes before
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Hazardous weather outlook, Aug 4, 5:00 AM EDT, 9 hours 59 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MORRISTOWN TN
500 AM EDT TUE AUG 4 2009

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-051000-
CHEROKEE-CLAY-SCOTT TN-CAMPBELL-CLAIBORNE-HANCOCK-HAWKINS-
SULLIVAN-JOHNSON-MORGAN-ANDERSON-UNION-GRAINGER-HAMBLEN-
NORTHWEST COCKE-COCKE SMOKY MOUNTAINS-NORTHWEST GREENE-
SOUTHEAST GREENE-WASHINGTON TN-UNICOI-NORTHWEST CARTER-
SOUTHEAST CARTER-ROANE-LOUDON-KNOX-JEFFERSON-NW BLOUNT-
BLOUNT SMOKY MOUNTAINS-NORTH SEVIER-SEVIER SMOKY MOUNTAINS-
SEQUATCHIE-BLEDSOE-RHEA-MEIGS-MCMINN-NORTHWEST MONROE-
SOUTHEAST MONROE-MARION-HAMILTON-BRADLEY-WEST POLK-EAST POLK-LEE-
WISE-SCOTT-RUSSELL-WASHINGTON-
500 AM EDT (400 AM CDT) TUE AUG 4 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST TENNESSEE...SOUTHWEST
VIRGINIA AND EXTREME SOUTHWEST NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT

UPPER-LEVEL DISTURBANCES WILL MOVE ACROSS THE REGION THIS AFTERNOON
AND TONIGHT...PRODUCING SCATTERED SHOWERS AND THUNDERSTORMS. SOME
STORMS MAY BECOME SEVERE THIS AFTERNOON AND TONIGHT...BRINGING THE
POSSIBILITY OF DAMAGING WINDS...LARGE HAIL...LOCALLY HEAVY RAINFALL
AND CLOUD TO GROUND LIGHTNING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A WEAK COLD FRONT WILL SETTLE INTO THE OHIO RIVER VALLEY ON
WEDNESDAY...AND BECOME STATIONARY NEAR THE SOUTHERN APPALACHIAN
REGION THROUGH THE WEEKEND. AS AS RESULT...THERE WILL BE A CHANCE
FOR SHOWERS AND THUNDERSTORMS EACH DAY INTO THE WEEKEND...WITH A FEW
STORMS POSSIBLY BECOMING SEVERE EACH AFTERNOON AND EVENING. THE MAIN
THREATS WILL BE THE POSSIBILITY OF DAMAGING WINDS...LARGE HAIL...
LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND TONIGHT.

DMG

In the hours before

Special weather statement, Aug 4, 2:54 PM EDT, 5 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MORRISTOWN TN
254 PM EDT TUE AUG 4 2009

TNZ014-015-VAZ001-042000-
CLAIBORNE-HANCOCK-LEE-
254 PM EDT TUE AUG 4 2009

...A STRONG THUNDERSTORM WILL BE AFFECTING CLAIBORNE...HANCOCK AND
LEE COUNTIES...

AT 253 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR FERNDALE...MOVING EAST AT 15 MPH.

PEA SIZE HAIL...AND WINDS 30 TO 40 MPH ARE EXPECTED WITH THIS STORM.

IN ADDITION TO SMALL HAIL AND GUSTY WINDS...FREQUENT CLOUD TO GROUND
LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS IMMEDIATELY
LIGHTNING IS ONE OF NATURES PRIMARY KILLERS ASSOCIATED WITH
THUNDERSTORMS. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE
ENOUGH TO BE STRUCK BY LIGHTNING.

DH

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 4, 3:40 PM EDTSevere Thunderstorm WarningMRXMorgan, Scott65 min
Aug 4, 3:48 PM EDTSevere Thunderstorm WarningMRXClaiborne, Grainger, Hamblen, Union57 min
Aug 4, 4:25 PM EDTSevere Thunderstorm WarningMRXAnderson, Campbell, Claiborne, Knox, Union65 min
Aug 4, 4:43 PM EDTSevere Thunderstorm WarningMRXAnderson, Campbell, Claiborne, Morgan, Scott32 min
Aug 4, 4:58 PM EDTAreal Flood AdvisoryMRXAnderson, Campbell, Claiborne, Grainger, Hancock, Knox and 3 more3 hr
Aug 4, 5:07 PM EDTSevere Thunderstorm WarningMRXAnderson, Morgan, Roane38 min
Aug 4, 5:15 PM EDTSevere Thunderstorm WarningMRXClaiborne, Cocke, Grainger, Greene, Hamblen, Hancock and 5 more60 min
Aug 4, 5:22 PM EDTAreal Flood AdvisoryMRXCocke, Grainger, Greene, Hamblen, Hancock, Hawkins and 3 more3 hr
Aug 4, 5:23 PM EDTSevere Thunderstorm WarningMRXAnderson, Blount, Knox67 min
Aug 4, 5:46 PM EDTSevere Thunderstorm WarningMRXAnderson, Morgan, Roane29 min
Aug 4, 6:04 PM EDTSevere Thunderstorm WarningMRXCocke, Greene56 min
Aug 4, 6:13 PM EDTSevere Thunderstorm WarningMRXAnderson, Blount, Knox, Loudon, Roane47 min
Aug 4, 6:21 PM EDTAreal Flood AdvisoryMRXAnderson, Blount, Knox, Loudon, Roane3 hr
Aug 4, 6:57 PM EDTAreal Flood WarningMRXRoane6 hr

Nearby

Severe Thunderstorm Warnings in Tennessee, 2009Every severe thunderstorm warning in 2009

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.