Alert archive / Tennessee / Special Weather Statements in 2018

Special Weather Statement, NWS Nashville, TN

August 20, 2018Sumner County, Tennessee

NWS Nashville, TN issued this special weather statement at Aug 20, 2018, 11:58 PM CDT for Sumner County, Tennessee. It was in force for 47 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 20, 2018, 11:58 PM CDT (04:58 UTC)
Expired: Aug 21, 2018, 12:45 AM CDT
In force: 47 min
Issued by: NWS Nashville, TN

County Sumner County, TN

The radar

The Nashville radar (KOHX), 38 km from the middle of the area, began a volume at 04:57 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 00:00Z, 5.0 hours before the alert went out and 51 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: 259 J/kg
Mixed-layer CIN: -65 J/kg
Mixed-layer LCL: 1225 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 115 m²/s²
0-3 km storm-relative helicity: 153 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 4.9

Open this sounding in Storm Lab

The text

As transmitted.

<!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>

What forecasters said that day

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

NWS Nashville, TN wrote its last area forecast discussion before this special weather statement went out at Aug 20, 11:44 PM CDT, 14 minutes earlier.

Area forecast discussion, Aug 20, 11:44 PM CDT, 14 minutes before

Area Forecast Discussion
National Weather Service Nashville TN
1144 PM CDT Mon Aug 20 2018

.UPDATE...
FOR 06Z AVIATION DISCUSSION.

&&

.DISCUSSION...

Strong storms currently clipping the northwest likely bulk of
stronger development tonight, thus plan of dropping watch behind.
Cold front is just west of MS river and is expected to continue
eastward track...pushing across the area overnight into late Tuesday
morning. While SVR threat minimal, scattered storms expected to
continue ahead of boundary most the night. Will make small adjustments
to reflect current trends and make a few temps tweaks as well.

&&

.AVIATION...
06Z TAF DISCUSSION.

Cold front now approaching the MS river this evening. Currently
just isolated to scattered showers and tstms are working across
the mid state. The aforementioned frontal boundary will move east
and should clear our eastern most counties between 12z and 18z.
Will go ahead and include a period of vcnty for showers and tstms
through 12z. Some isol activity could still hang on through the
day near csv. Otw, lower, but mainly non ifr, cloudiness will
persist for the most part through the taf period.

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

DISCUSSION......07
AVIATION........21

Hazardous weather outlook, Aug 20, 10:57 PM CDT, 1 hour 1 minute before

Hazardous Weather Outlook...Updated
National Weather Service Nashville TN
1057 PM CDT Mon Aug 20 2018

TNZ005>011-023>034-056>066-075-077>080-093>095-211015-
Stewart-Montgomery-Robertson-Sumner-Macon-Clay-Pickett-Houston-
Humphreys-Dickson-Cheatham-Davidson-Wilson-Trousdale-Smith-
Jackson-Putnam-Overton-Fentress-Perry-Hickman-Lewis-Williamson-
Maury-Marshall-Rutherford-Cannon-De Kalb-White-Cumberland-Bedford-
Coffee-Warren-Grundy-Van Buren-Wayne-Lawrence-Giles-
1057 PM CDT Mon Aug 20 2018

This Hazardous Weather Outlook is for portions of Middle
Tennessee.

.DAY ONE...Tonight

A broken band of storms will occur tonight ahead of a cold front
approaching Middle Tennessee from the west. Some of these storms
could become strong, mainly in areas west of I-65.
Strong gusty winds are the primary threat. The peak time for any
strong storms is between 10 pm and midnight tonight.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.

21

In the hours before

Special weather statement, Aug 20, 9:37 PM CDT, 2 hours 21 minutes before

Special Weather Statement
National Weather Service Nashville TN
937 PM CDT MON AUG 20 2018

TNZ005-006-023-210315-
Stewart TN-Montgomery TN-Houston TN-
937 PM CDT MON AUG 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN MONTGOMERY...STEWART AND
NORTHERN HOUSTON COUNTIES UNTIL 1015 PM CDT...

At 936 PM CDT, Doppler radar was tracking a strong thunderstorm near
Paris Landing State Park, moving northeast at 45 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Dover, Erin, Clarksville, Tennessee Ridge, Big Rock, Cumberland City,
Land Between The Lakes, Houston County Airport, Indian Mound, Palmyra
and Woodlawn.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

A Severe Thunderstorm Watch remains in effect until midnight CDT for
Middle Tennessee.

LAT...LON 3666 8785 3663 8785 3664 8740 3634 8750
      3630 8795 3635 8798 3640 8803 3650 8805
      3652 8804 3656 8803 3668 8807
TIME...MOT...LOC 0236Z 239DEG 48KT 3642 8798

07

Special weather statement, Aug 20, 10:16 PM CDT, 1 hour 42 minutes before

Special Weather Statement
National Weather Service Nashville TN
1016 PM CDT MON AUG 20 2018

TNZ005-006-023-210400-
Stewart TN-Montgomery TN-Houston TN-
1016 PM CDT MON AUG 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR MONTGOMERY...EASTERN STEWART AND
NORTHERN HOUSTON COUNTIES UNTIL 1100 PM CDT...

At 1015 PM CDT, Doppler radar was tracking a strong thunderstorm 8
miles southeast of Big Rock, or 10 miles east of Dover, moving
northeast at 40 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Dover, Erin, Clarksville, Tennessee Ridge, Big Rock, Cumberland City,
Indian Mound, Palmyra, Cunningham and Woodlawn.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

A Severe Thunderstorm Watch remains in effect until midnight CDT for
Middle Tennessee.

LAT...LON 3662 8713 3661 8712 3633 8730 3632 8738
      3634 8751 3631 8752 3626 8792 3663 8776
      3664 8752 3664 8711
TIME...MOT...LOC 0315Z 239DEG 48KT 3649 8766

07

Special weather statement, Aug 20, 11:05 PM CDT, 53 minutes before

Special Weather Statement
National Weather Service Nashville TN
1105 PM CDT MON AUG 20 2018

TNZ006-007-210445-
Robertson TN-Montgomery TN-
1105 PM CDT MON AUG 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR MONTGOMERY AND NORTHWESTERN
ROBERTSON COUNTIES UNTIL 1145 PM CDT...

At 1105 PM CDT, Doppler radar was tracking a strong thunderstorm near
Clarksville, moving northeast at 45 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Clarksville, Adams and Cunningham.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3645 8711 3645 8712 3644 8715 3643 8715
      3635 8745 3664 8749 3665 8700
TIME...MOT...LOC 0405Z 239DEG 49KT 3657 8729

07

Special weather statement, Aug 20, 11:58 PM CDT, 0 minutes before

Special Weather Statement
National Weather Service Nashville TN
1158 PM CDT MON AUG 20 2018

TNZ008-009-210545-
Sumner TN-Macon TN-
1158 PM CDT MON AUG 20 2018

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN SUMNER AND NORTHWESTERN
MACON COUNTIES UNTIL 1245 AM CDT...

At 1158 PM CDT, Doppler radar was tracking a strong thunderstorm near
Gallatin, moving northeast at 35 mph.

Winds in excess of 30 mph will be possible with this storm.

Locations impacted include...
Gallatin, Westmoreland, Oak Grove, Bledsoe Creek State Park,
Cottontown and Bethpage.

LAT...LON 3663 8601 3648 8620 3649 8624 3645 8624
      3645 8626 3643 8627 3632 8641 3644 8657
      3665 8644
TIME...MOT...LOC 0458Z 224DEG 30KT 3645 8641

27

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 9:37 PM CDT	Special Weather Statement	OHX	Stewart	38 min
Aug 20, 10:16 PM CDT	Special Weather Statement	OHX	Montgomery, Stewart	44 min
Aug 20, 11:05 PM CDT	Special Weather Statement	OHX	Montgomery	40 min
Aug 21, 12:03 AM CDT	Special Weather Statement	OHX	Wilson	42 min
Aug 21, 12:08 AM CDT	Severe Thunderstorm Warning	OHX	Macon, Sumner, Trousdale	37 min
Aug 21, 12:13 AM CDT	Severe Thunderstorm Warning	OHX	Macon, Sumner, Trousdale, Wilson	47 min

Nearby

Special Weather Statements in Tennessee, 2018 Every special weather statement 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.