Alert archive / Tennessee / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 147, NWS Morristown, TN

July 20, 20184 counties in Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Jul 20, 2018, 11:11 PM CDT for 4 counties in Tennessee. It was in force for 49 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 20, 2018, 11:11 PM CDT (04:11 UTC)
Expired
Jul 21, 2018, 12:00 AM CDT
In force
49 min
Issued by
NWS Morristown, TN
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Bledsoe County, TN, Hamilton County, TN, Rhea County, TN, Sequatchie County, TN

The radar

The Northeast Alabama radar (KHTX), 100 km from the middle of the area, began a volume at 04:12 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
Jul 20, 7:02 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 4.2 hours before the alert went out and 150 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 00:00Z on 2018-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3305 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 2018-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 square meters per square second.1939587897Sfc1 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
3305 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
1217 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
169 m²/s²
Significant tornado parameter
2.2
Supercell composite
11.6

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 20, 7:38 PM CDT, 3 hours 33 minutes earlier.

Area forecast discussion, Jul 20, 7:38 PM CDT, 3 hours 33 minutes before
Area Forecast Discussion
National Weather Service Morristown TN
838 PM EDT Fri Jul 20 2018

.DISCUSSION...Showers and storms currently across southeastern KY
and the northern Cumberland Plateau will continue to drift east
southeast into the TN Valley this evening. The highest
instability values remain across the central TN Valley and
westward back toward the Cumberland Plateau. This area of moderate
instability combined with 40 to 50 Knots of effective bulk shear
will allow storms to maintain their strength as they drop down
into our area. Low level shear is lacking right now so expect any
rotation to remain confined to the mid levels unless a storm can
latch onto a good boundary. Models do show low level shear
increasing here in a few hours though, thus allowing for the
current tornado watch. Wind damage and large hail will be the
main threats with these storms but there is also the possibility
of an isolated tornado due to the shear in place. Models still
uncertain what happens later tonight after this first wave of
storms rolls. However, thinking as of now is this line that is
currently moving in will be the main show. New zones issued for
tornado watch wording.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             72  89  70  85 /  60  60  60  50
Knoxville McGhee Tyson Airport, TN  70  85  68  82 /  60  60  60  70
Oak Ridge, TN                       70  85  68  82 /  70  60  60  70
Tri Cities Airport, TN              66  82  65  79 /  60  70  70  70

&&

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

SR
Hazardous weather outlook, Jul 20, 2:21 PM CDT, 8 hours 50 minutes before
Hazardous Weather Outlook
National Weather Service Morristown TN
321 PM EDT Fri Jul 20 2018

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-211930-
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-
321 PM EDT Fri Jul 20 2018 /221 PM CDT Fri Jul 20 2018/

This Hazardous Weather Outlook is for portions of Southwest North
Carolina...East Tennessee and Southwest Virginia.

.DAY ONE...This Afternoon and Tonight

Showers and thunderstorms are likely tonight across much of the
area, some of which may reach severe levels. The strongest storms
are expected to move out of Kentucky into middle and east
Tennessee late tonight, moving quickly into southeast Tennessee
and southwest North Carolina into early morning Saturday. Some of
these thunderstorms will be capable of producing damaging winds,
large hail, and brief heavy rainfall. An isolated tornado cannot
be ruled out, particularly across southern portions of the
Tennessee Valley.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

The atmosphere will remain unstable into Saturday and strong to
severe thunderstorms will again be possible Saturday afternoon
into the evening. The main threats with any stronger storms will
be damaging winds, large hail and brief heavy rainfall.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed tonight.

In the hours before

Local storm report, Jul 20, 10:25 PM CDT, 46 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, Jul 20, 10:31 PM CDT, 40 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, Jul 20, 10:32 PM CDT, 39 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, Jul 20, 10:44 PM CDT, 27 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, Jul 20, 11:02 PM CDT, 9 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, Jul 20, 11:11 PM CDT, 0 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
Jul 20, 8:02 PM CDTSevere Thunderstorm WarningMRXClaiborne, Hancock58 min
Jul 20, 8:12 PM CDTSevere Thunderstorm WarningMRXCampbell, Claiborne, Scott48 min
Jul 20, 8:42 PM CDTSevere Thunderstorm WarningMRXGrainger, Hamblen, Hawkins63 min
Jul 20, 8:56 PM CDTSevere Thunderstorm WarningMRXAnderson, Campbell, Claiborne, Union49 min
Jul 20, 9:10 PM CDTSevere Thunderstorm WarningMRXCocke, Greene, Jefferson, Sullivan, Unicoi, Washington65 min
Jul 20, 9:17 PM CDTSevere Thunderstorm WarningMRXAnderson, Blount, Knox, Sevier58 min
Jul 20, 9:31 PM CDTTornado WarningMRXBledsoe, Rhea44 min
Jul 20, 9:44 PM CDTSevere Thunderstorm WarningMRXHamblen16 min
Jul 20, 9:48 PM CDTSevere Thunderstorm WarningMRXCarter, Johnson, Unicoi57 min
Jul 20, 10:10 PM CDTTornado WarningMRXBledsoe, Meigs, Rhea50 min
Jul 20, 10:13 PM CDTSevere Thunderstorm WarningMRXCocke, Sevier32 min
Jul 20, 10:18 PM CDTSevere Thunderstorm WarningMRXBledsoe, Rhea42 min
Jul 20, 10:42 PM CDTSevere Thunderstorm WarningMRXBradley, McMinn, Meigs, Rhea48 min
Jul 20, 10:47 PM CDTAreal Flood AdvisoryMRXBledsoe, Meigs, Rhea, Roane3 hr
Jul 20, 11:02 PM CDTSpecial Weather StatementMRXBledsoe43 min
Jul 20, 11:14 PM CDTSpecial Weather StatementMRXScott46 min
Jul 20, 11:24 PM CDTSevere Thunderstorm WarningMRXBradley, McMinn, Meigs, Polk51 min
Jul 20, 11:55 PM CDTSevere Thunderstorm WarningMRXBledsoe, Hamilton, Meigs, Rhea50 min
Jul 20, 11:58 PM CDTAreal Flood AdvisoryMRXMcMinn, Meigs, Rhea3 hr
Jul 20, 11:58 PM CDTSevere Thunderstorm WarningMRXPolk62 min
Jul 21, 12:16 AM CDTAreal Flood AdvisoryMRXBledsoe, Rhea3 hr
Jul 21, 12:21 AM CDTSevere Thunderstorm WarningMRXBledsoe, Rhea39 min
Jul 21, 12:27 AM CDTSevere Thunderstorm WarningMRXAnderson, Campbell, Claiborne, Scott48 min
Jul 21, 12:28 AM CDTSevere Thunderstorm WarningMRXBradley, McMinn47 min
Jul 21, 1:02 AM CDTSevere Thunderstorm WarningMRXBradley, Polk28 min
Jul 21, 1:11 AM CDTSevere Thunderstorm WarningMRXAnderson, Campbell, Morgan, Roane, Scott52 min
Jul 21, 1:16 AM CDTSevere Thunderstorm WarningMRXAnderson, Campbell, Claiborne, Grainger, Knox, Union59 min
Jul 21, 1:39 AM CDTAreal Flood AdvisoryMRXBradley, McMinn, Polk3 hr
Jul 21, 1:54 AM CDTSpecial Weather StatementMRXBlount, Loudon, Roane66 min
Jul 21, 2:06 AM CDTSevere Thunderstorm WarningMRXBledsoe, Rhea39 min
Jul 21, 2:10 AM CDTSpecial Weather StatementMRXCocke, Grainger, Hamblen, Jefferson50 min
Jul 21, 2:30 AM CDTSevere Thunderstorm WarningMRXBledsoe, Hamilton, Meigs, Rhea45 min
Jul 21, 2:36 AM CDTAreal Flood WarningMRXBledsoe, Bradley, Hamilton, McMinn, Meigs, Rhea3 hr
Jul 21, 2:41 AM CDTSevere Thunderstorm WarningMRXHamilton, Marion, Sequatchie48 min
Jul 21, 2:53 AM CDTSevere Thunderstorm WarningMRXMcMinn, Monroe41 min
Jul 21, 3:05 AM CDTSevere Thunderstorm WarningMRXBradley, Hamilton, McMinn, Polk40 min
Jul 21, 3:33 AM CDTAreal Flood AdvisoryMRXBradley, Hamilton, Marion, Polk117 min
Jul 21, 5:39 AM CDTSevere Thunderstorm WarningMRXBledsoe36 min
Jul 21, 6:05 AM CDTSevere Thunderstorm WarningMRXBledsoe, Hamilton, Meigs, Rhea25 min
Jul 21, 6:24 AM CDTSpecial Weather StatementMRXBradley, Polk36 min
Jul 21, 3:06 PM CDTSpecial Weather StatementMRXKnox39 min
Jul 21, 3:17 PM CDTSpecial Weather StatementMRXMonroe43 min
Jul 21, 3:45 PM CDTSpecial Weather StatementMRXHancock, Hawkins60 min
Jul 21, 3:47 PM CDTSpecial Weather StatementMRXSevier58 min
Jul 21, 4:12 PM CDTSpecial Weather StatementMRXBradley63 min
Jul 21, 4:19 PM CDTSevere Thunderstorm WarningMRXBradley, Hamilton, McMinn, Meigs56 min
Jul 21, 4:33 PM CDTSpecial Weather StatementMRXMonroe42 min
Jul 21, 4:44 PM CDTSpecial Weather StatementMRXGrainger46 min
Jul 21, 4:49 PM CDTSpecial Weather StatementMRXBradley26 min
Jul 21, 4:53 PM CDTSevere Thunderstorm WarningMRXBradley, Hamilton37 min
Jul 21, 5:07 PM CDTSpecial Weather StatementMRXPolk53 min
Jul 21, 5:24 PM CDTSpecial Weather StatementMRXMonroe51 min
Jul 21, 5:26 PM CDTSevere Thunderstorm WarningMRXPolk49 min
Jul 21, 6:00 PM CDTSpecial Weather StatementMRXBlount30 min
Jul 21, 6:15 PM CDTSevere Thunderstorm WarningMRXBlount, Sevier34 min
Jul 20, 7:14 PM CDTSpecial Weather StatementMRXScott, Wise, City of Norton46 min
Jul 20, 8:23 PM CDTSevere Thunderstorm WarningMRXLee37 min
Jul 20, 10:50 PM CDTAreal Flood AdvisoryMRXWise, City of Norton3 hr
Jul 21, 3:15 PM CDTSpecial Weather StatementMRXRussell45 min
Jul 21, 3:59 PM CDTSpecial Weather StatementMRXScott61 min
Jul 21, 4:43 PM CDTSpecial Weather StatementMRXRussell47 min
Jul 21, 5:34 PM CDTSpecial Weather StatementMRXSmyth41 min
Jul 21, 5:10 PM CDTSpecial Weather StatementMRXCherokee50 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 2018Every severe thunderstorm warning in 2018

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.