Alert archive / Tennessee / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 218, NWS Morristown, TN

July 21, 2008Knox County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Jul 21, 2008, 5:59 PM EDT for Knox County, Tennessee. It was in force for 25 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: Jul 21, 2008, 5:59 PM EDT (21:59 UTC)
Expired: Jul 21, 2008, 6:24 PM EDT
In force: 25 min
Issued by: NWS Morristown, TN
Area: Storm-based polygon

County Knox County, TN

The watch it was issued in

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

Issued	Product	Office	Lasted
Jul 21, 3:44 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 10.0 hours before the alert went out and 240 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: 2596 J/kg
Mixed-layer CIN: -51 J/kg
Mixed-layer LCL: 1158 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 45 m²/s²
0-3 km storm-relative helicity: 83 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 Jul 21, 5:03 PM EDT, 56 minutes earlier.

Area forecast discussion, Jul 21, 5:03 PM EDT, 56 minutes before

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Hazardous weather outlook, Jul 21, 9:20 AM EDT, 8 hours 39 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
920 AM EDT MON JUL 21 2008

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-221200-
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-
920 AM EDT MON JUL 21 2008 /820 AM CDT MON JUL 21 2008/

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

.DAY ONE...TODAY AND TONIGHT

A COLD FRONT WILL REMAIN NEARLY STATIONARY ACROSS THE OHIO VALLEY.
HOWEVER UPPER LEVEL FLOW WILL CAUSE SHOWERS AND THUNDERSTORMS TO
MOVE SOUTHEAST TOWARDS NORTHEAST TENNESSEE AND SOUTHWEST VIRGINIA
THIS AFTERNOON. INCREASED MOISTURE AND DAYTIME HEATING COMBINED
WITH HOT TEMPERATURES WILL CAUSE A FEW STORMS TO BE STRONG AND
POSSIBLY SEVERE LATE THIS AFTERNOON AND EVENING WITH DAMAGING
WINDS AND LARGE HAIL POSSIBLE ESPECIALLY ACROSS NORTHERN TENNESSEE
AND SOUTHWEST VIRGINIA.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

UPPER LEVEL TROUGH DROPPING SOUTH AND EAST FROM THE OHIO VALLEY
INTO THE TENNESSEE VALLEY AND ACCOMPANYING COLD FRONT WILL CREATE AN
UNSTABLE ENVIRONMENT WHEN COMBINED WITH AMPLE MOISTURE AND DAYTIME
HEATING TUESDAY FOR POSSIBLE SEVERE THUNDERSTORMS WITH DAMAGING
WINDS THE MAIN THREAT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY DUE TO THE ISOLATED
NATURE OF THE SEVERE WEATHER...BUT MAY BE NEEDED TUESDAY AFTERNOON
AND EVENING.

TD

In the hours before

Local storm report, Jul 21, 4:20 PM EDT, 1 hour 39 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
420 PM EDT MON JUL 21 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0415 PM     TSTM WND DMG     ROCKWOOD                35.87N 84.68W
07/21/2008                   ROANE              TN   AMATEUR RADIO

            NUMEROUS TREES DOWN IN ROCKWOOD. REPORTED BY SHERIFFS
            DISPATCH OFFICE.

&&

Local storm report, Jul 21, 4:52 PM EDT, 1 hour 7 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
452 PM EDT MON JUL 21 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0425 PM     TSTM WND DMG     ONEIDA                  36.50N 84.51W
07/21/2008                   SCOTT              TN   LAW ENFORCEMENT

            FEW TREES DOWN.

&&

Local storm report, Jul 21, 4:56 PM EDT, 1 hour 3 minutes before

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Local storm report, Jul 21, 5:27 PM EDT, 32 minutes before

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Local storm report, Jul 21, 5:37 PM EDT, 22 minutes before

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Local storm report, Jul 21, 5:47 PM EDT, 12 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 3:15 PM EDT	Severe Thunderstorm Warning	MRX	Grainger, Hamblen	45 min
Jul 21, 3:18 PM EDT	Severe Thunderstorm Warning	MRX	Hawkins, Sullivan	42 min
Jul 21, 3:23 PM EDT	Severe Thunderstorm Warning	MRX	Sullivan	52 min
Jul 21, 3:43 PM EDT	Severe Thunderstorm Warning	MRX	Campbell, Claiborne, Scott	62 min
Jul 21, 3:53 PM EDT	Severe Thunderstorm Warning	MRX	Loudon, McMinn, Meigs, Rhea, Roane	52 min
Jul 21, 4:15 PM EDT	Severe Thunderstorm Warning	MRX	Cocke	30 min
Jul 21, 4:18 PM EDT	Severe Thunderstorm Warning	MRX	Carter, Johnson, Sullivan	57 min
Jul 21, 4:26 PM EDT	Severe Thunderstorm Warning	MRX	Anderson, Campbell, Claiborne, Grainger, Scott, Union	64 min
Jul 21, 4:45 PM EDT	Severe Thunderstorm Warning	MRX	Loudon, McMinn, Meigs, Monroe, Rhea, Roane	60 min
Jul 21, 4:53 PM EDT	Severe Thunderstorm Warning	MRX	Anderson, Morgan, Roane	67 min
Jul 21, 5:01 PM EDT	Areal Flood Advisory	MRX	McMinn, Meigs, Rhea, Roane	3 hr
Jul 21, 5:01 PM EDT	Severe Thunderstorm Warning	MRX	Knox, Union	59 min
Jul 21, 5:11 PM EDT	Severe Thunderstorm Warning	MRX	Carter, Unicoi	20 min
Jul 21, 5:13 PM EDT	Flash Flood Warning	MRX	Meigs, Rhea, Roane	81 min
Jul 21, 5:13 PM EDT	Severe Thunderstorm Warning	MRX	Blount, Cocke, Jefferson, Loudon, Monroe, Sevier	62 min
Jul 21, 5:20 PM EDT	Severe Thunderstorm Warning	MRX	Grainger, Jefferson	40 min
Jul 21, 5:29 PM EDT	Areal Flood Advisory	MRX	Knox	69 min
Jul 21, 5:36 PM EDT	Severe Thunderstorm Warning	MRX	Grainger, Hamblen	54 min
Jul 21, 5:45 PM EDT	Severe Thunderstorm Warning	MRX	Bledsoe, Loudon, McMinn, Meigs, Monroe, Rhea and 1 more	60 min
Jul 21, 5:53 PM EDT	Severe Thunderstorm Warning	MRX	Marion	52 min
Jul 21, 6:03 PM EDT	Severe Thunderstorm Warning	MRX	Bradley, Hamilton, Polk	57 min
Jul 21, 6:09 PM EDT	Severe Thunderstorm Warning	MRX	Cocke, Jefferson	24 min
Jul 21, 6:15 PM EDT	Severe Thunderstorm Warning	MRX	Blount, Cocke, Jefferson, Loudon, Monroe, Sevier	60 min
Jul 21, 6:48 PM EDT	Severe Thunderstorm Warning	MRX	Polk	42 min
Jul 21, 6:57 PM EDT	Severe Thunderstorm Warning	MRX	Bradley, Hamilton, Polk	48 min
Jul 21, 7:14 PM EDT	Severe Thunderstorm Warning	MRX	Marion	46 min
Jul 21, 6:41 PM EDT	Severe Thunderstorm Warning	MRX	Cherokee, Clay	54 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 2008 Every severe thunderstorm warning in 2008

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.