Alert archive / Tennessee / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 183, NWS Morristown, TN

August 21, 2007Sevier County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Aug 21, 2007, 3:24 PM EDT for Sevier County, Tennessee. It was in force for 35 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 21, 2007, 3:24 PM EDT (19:24 UTC)
Expired
Aug 21, 2007, 3:59 PM EDT
In force
35 min
Issued by
NWS Morristown, TN
Area
Counties, with a storm outline in the text

County Sevier County, TN

The radar

The Knoxville radar (KMRX), 44 km from the middle of the area, began a volume at 19:26 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, 7.4 hours before the alert went out and 279 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 2007-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 266 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 2007-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 74 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
266 J/kg
Mixed-layer CIN
-75 J/kg
Mixed-layer LCL
1598 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
74 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

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 Aug 21, 2:26 PM EDT, 58 minutes earlier.

Area forecast discussion, Aug 21, 2:26 PM EDT, 58 minutes before
AREA FORECAST DISCUSSION...UPDATED FIRE WEATHER WATCH
NATIONAL WEATHER SERVICE MORRISTOWN TN
226 PM EDT TUE AUG 21 2007

.SHORT TERM (TONIGHT AND WEDNESDAY)...DIURNALLY INDUCED SCATTERED
THUNDERSTORMS WILL CONTINUE OVER THE MRX CWA INTO THE EVENING
HOURS.  ADDITIONALLY...A BAND OF SHOWERS AND THUNDERSTORMS ALONG A
WEAK SHORT WAVE MAY KEEP SOME ISOLATED CONVECTION INTO THE OVERNIGHT
HOURS.  ON WEDNESDAY...HIGH PRESSURE REMAINS IN CONTROL WITH ANOTHER
WEAK IMPULSE DRIFTING THROUGH TO OUR NORTH...FOR A SLIGHT CHANCE OF
THUNDERSTORMS.  OTHERWISE...CONTINUED HOT AND HUMID THROUGH THE SHORT
TERM.

DUE TO THE VERY DRY FUEL CONDITIONS...WILL CONTINUE RED FLAG WARNING
UNTIL 8 PM TODAY AND FIRE WEATHER WATCH FOR WEDNESDAY.

.LONG TERM (WEDNESDAY NIGHT THROUGH TUESDAY)...RIDGE OF HIGH
PRESSURE WILL REMAIN CENTERED ACROSS THE GULF COASTS STATES INTO
THE TENNESSEE VALLEY THROUGH FRIDAY. ONLY FORCING FOR CONVECTION
WILL BE OROGRAHICS...SO WILL MAINTAIN A SLIGHT POP FOR THE HIGHER ELEVATIONS.

FOR SATURDAY AND SUNDAY...A SHORT-WAVE TROUGH WILL MOVE ACROSS THE
GREAT LAKES AND OHIO VALLEY FLATTENING THE RIDGE ACROSS THE
FORECAST AREA. A WEAK COLD FRONT WILL MOVE INTO THE FORECAST AREA
FOR SUNDAY BEFORE STALLING AND DISSIPATING. WILL CALL FOR CHANCE
POPS FOR THE HIGHER TERRAIN AND SLIGHT POPS IN THE VALLEY FOR
SUNDAY THROUGH TUESDAY. HAVE TRENDED A DEGREE OR TWO HIGHER THAN
GFX MAX TEMPERATURES DUE TO DRY SOIL CONDITIONS. UPPER RIDGE RE-
BUILDS OVER THE REGION FOR MONDAY AND TUESDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             72  98  73  98  73 /  10  10  10  10  10
KNOXVILLE MCGHEE TYSON AIRPORT, TN  71  95  73  96  73 /  10  10  10  10  10
OAK RIDGE, TN                       70  96  73  96  73 /  10  10  10  10  10
TRI CITIES AIRPORT, TN              67  94  65  92  67 /  20  20  10  10  10

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR THE FOLLOWING ZONES: CHEROKEE...CLAY.

     RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR THE FOLLOWING
     ZONES: CHEROKEE...CLAY.

TN...NONE.
VA...NONE.

&&

DH/MJB
Hazardous weather outlook, Aug 21, 3:29 AM EDT, 11 hours 55 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MORRISTOWN TN
329 AM EDT TUE AUG 21 2007

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-220730-
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-
329 AM EDT TUE AUG 21 2007 /229 AM CDT TUE AUG 21 2007/

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

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

In the hours before

Special weather statement, Aug 21, 2:12 PM EDT, 1 hour 12 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MORRISTOWN TN
212 PM EDT TUE AUG 21 2007

TNZ016-211915-
HAWKINS-
212 PM EDT TUE AUG 21 2007

...A STRONG THUNDERSTORM WAS AFFECTING HAWKINS COUNTY...

AT 206 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR ROGERSVILLE. THIS STORM WAS  NEARLY
STATIONARY.

SMALL HAIL...AND WINDS AROUND 40 MPH ARE EXPECTED WITH THIS STORM.

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

MJB
Special weather statement, Aug 21, 2:53 PM EDT, 31 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Special weather statement, Aug 21, 2:59 PM EDT, 25 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Local storm report, Aug 21, 3:13 PM EDT, 11 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Special weather statement, Aug 21, 3:22 PM EDT, 2 minutes before
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 11:47 AM EDTFire Weather WatchMRX23 hr
Aug 21, 1:50 PM EDTSevere Thunderstorm WarningMRXKnox40 min
Aug 21, 2:17 PM EDTSevere Thunderstorm WarningMRXHawkins28 min
Aug 21, 2:33 PM EDTSevere Thunderstorm WarningMRXJohnson42 min
Aug 21, 1:12 PM EDTSevere Thunderstorm WarningMRXWashington18 min
Aug 21, 11:47 AM EDTRed Flag WarningMRX8 hr

Nearby

Severe Thunderstorm Warnings in Tennessee, 2007Every severe thunderstorm warning in 2007

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.