Alert archive / Tennessee / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 137, NWS Morristown, TN

June 11, 2009Blount County, Knox County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Jun 11, 2009, 1:28 PM EDT for Blount County, Knox County, Tennessee. It was in force for 62 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
Jun 11, 2009, 1:28 PM EDT (17:28 UTC)
Expired
Jun 11, 2009, 2:30 PM EDT
In force
62 min
Issued by
NWS Morristown, TN
Area
Storm-based polygon

Counties Blount County, TN, Knox County, TN

The radar

The Knoxville radar (KMRX), 60 km from the middle of the area, began a volume at 17:28 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jun 11, 12:18 PM EDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 5.5 hours before the alert went out and 242 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 2009-06-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2748 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 2009-06-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 square meters per square second.193958Sfc1 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
2748 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
587 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.8
Supercell composite
4.5

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 Jun 11, 10:15 AM EDT, 3 hours 13 minutes earlier.

Area forecast discussion, Jun 11, 10:15 AM EDT, 3 hours 13 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1015 AM EDT THU JUN 11 2009

.DISCUSSION...
CURRENT SURFACE ANALYSIS SHOWS A QUASI-STATIONARY FRONTAL BOUNDARY
REMAINING OVER THE OHIO RIVER VALLEY...WITH A WARM AND MOIST AIR
MASS OVER THE FORECAST AREA. SATELLITE AND RADAR IMAGERY REVEAL A
MESOSCALE CONVECTIVE VORTEX OVER MIDDLE TN THAT HAS INITIATED
CLUSTERS OF STRONG TO SEVERE CONVECTION. THIS MCV WILL CONTINUE TO
MOVE EAST ACROSS THE TN RIVER VALLEY THIS MORNING...AND WILL LIKELY
AFFECT THE FORECAST AREA DURING THE AFTERNOON HOURS. MODEL SOUNDINGS
REVEAL A MODERATELY UNSTABLE AIR MASS DEVELOPING AGAIN THIS
AFTERNOON...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA.

HAVE ALREADY UPDATED THE FORECAST TO MENTION THE SEVERE TSTORM
WATCH...WITH THE REST OF THE FORECAST APPEARING TO BE IN GOOD SHAPE
WITH NO FURTHER UPDATES PLANNED.
&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

DMG
Hazardous weather outlook, Jun 11, 5:07 AM EDT, 8 hours 21 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MORRISTOWN TN
507 AM EDT THU JUN 11 2009

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-120915-
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-
507 AM EDT THU JUN 11 2009 /407 AM CDT THU JUN 11 2009/

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL DEVELOP...MAINLY THIS AFTERNOON AND
LINGER THROUGHOUT THE EVENING...AS A COLD FRONT SAGS SLOWLY SOUTH.
A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE...ESPECIALLY THIS
AFTERNOON AND EVENING. THE MAIN THREATS WILL BE DAMAGING WINDS OF
50 MPH OR MORE AND HAIL OF PENNY SIZE OR LARGER. BRIEF LOCALLY
HEAVY RAINS COULD OCCUR WITH THE STRONGEST STORMS...WITH FREQUENT
DEADLY LIGHTNING STRIKES IN AND NEAR ALL STORMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

A WEAK COLD FRONT WILL LINGER ACROSS THE REGION FRIDAY INTO
SATURDAY...HELPING SCATTERED THUNDERSTORMS TO CONTINUE. AN UPPER
LEVEL DISTURBANCE ON SUNDAY WILL ALSO PRODUCE MORE SHOWERS AND
SCATTERED THUNDERSTORMS.

ISOLATED STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE EACH
AFTERNOON AND EVENING...FROM FRIDAY THROUGH SUNDAY. THE MAIN THREATS
WILL BE DAMAGING DOWNBURSTS WINDS OF 50 MPH OR HIGHER AND LARGE
HAIL. LOCALLY HEAVY RAINS IN EXCESS OF ONE INCH WILL ALSO OCCUR
WITH THE STRONGER STORMS...AND FREQUENT DEADLY LIGHTNING STRIKES IN
AND NEAR ANY THUNDERSTORMS.

A RIDGE OF HIGH PRESSURE WILL BUILD EASTWARD FROM THE SOUTHERN
PLAINS MONDAY THROUGH WEDNESDAY. THIS SHOULD DECREASE THE CHANCES
OF THUNDERSTORMS FOR EARLY NEXT WEEK...WITH MAINLY ISOLATED
AFTERNOON AND EVENING STORMS DEVELOPING DURING THE HEAT OF THE DAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY...AND POSSIBLY AGAIN FRIDAY
AND SATURDAY.

TT/TG

In the hours before

Local storm report, Jun 11, 1:09 PM EDT, 19 minutes before
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Local storm report, Jun 11, 1:11 PM EDT, 17 minutes before
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Local storm report, Jun 11, 1:16 PM EDT, 12 minutes before
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Local storm report, Jun 11, 1:18 PM EDT, 10 minutes before
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Local storm report, Jun 11, 1:24 PM EDT, 4 minutes before
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Local storm report, Jun 11, 1:28 PM EDT, 0 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jun 10, 8:07 PM EDTSevere Thunderstorm WarningMRXLoudon, Morgan, Roane38 min
Jun 10, 8:19 PM EDTTornado WarningMRXLoudon, Morgan, Roane26 min
Jun 10, 8:42 PM EDTSevere Thunderstorm WarningMRXBlount, Loudon, Monroe48 min
Jun 10, 8:48 PM EDTSevere Thunderstorm WarningMRXLoudon, Roane27 min
Jun 10, 9:20 PM EDTSevere Thunderstorm WarningMRXMonroe25 min
Jun 11, 11:56 AM EDTSevere Thunderstorm WarningMRXBledsoe, Sequatchie64 min
Jun 11, 12:27 PM EDTSevere Thunderstorm WarningMRXHamilton, Marion48 min
Jun 11, 12:40 PM EDTSevere Thunderstorm WarningMRXMeigs, Rhea50 min
Jun 11, 12:44 PM EDTSevere Thunderstorm WarningMRXMorgan, Roane61 min
Jun 11, 12:50 PM EDTSevere Thunderstorm WarningMRXScott55 min
Jun 11, 12:54 PM EDTSevere Thunderstorm WarningMRXBradley, McMinn, Monroe, Polk51 min
Jun 11, 1:12 PM EDTSevere Thunderstorm WarningMRXAnderson, Campbell63 min
Jun 11, 1:18 PM EDTSevere Thunderstorm WarningMRXBlount, Loudon, McMinn, Meigs, Monroe57 min
Jun 11, 1:44 PM EDTSevere Thunderstorm WarningMRXBlount, Monroe, Polk46 min
Jun 11, 1:52 PM EDTSevere Thunderstorm WarningMRXClaiborne, Grainger, Union53 min
Jun 11, 2:11 PM EDTSevere Thunderstorm WarningMRXHamblen, Jefferson, Sevier64 min
Jun 11, 2:14 PM EDTSevere Thunderstorm WarningMRXBlount, Sevier61 min
Jun 11, 2:45 PM EDTSevere Thunderstorm WarningMRXClaiborne, Grainger, Hancock30 min
Jun 11, 2:57 PM EDTSevere Thunderstorm WarningMRXCocke, Greene, Hawkins63 min
Jun 11, 3:04 PM EDTSevere Thunderstorm WarningMRXCocke, Grainger, Greene, Hamblen, Hancock, Hawkins and 2 more26 min
Jun 11, 3:31 PM EDTSevere Thunderstorm WarningMRXUnicoi49 min
Jun 11, 3:36 PM EDTSevere Thunderstorm WarningMRXSullivan, Washington54 min
Jun 11, 4:11 PM EDTSevere Thunderstorm WarningMRXCarter34 min
Jun 11, 4:29 PM EDTSevere Thunderstorm WarningMRXJohnson, Sullivan46 min
Jun 11, 3:50 PM EDTSevere Thunderstorm WarningMRXScott55 min
Jun 11, 4:21 PM EDTSevere Thunderstorm WarningMRXWise, City of Norton39 min
Jun 11, 2:38 PM EDTSevere Thunderstorm WarningMRXCherokee, Clay41 min

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.