Tornadoes · United States · Kentucky · 2013

EF0 tornado, Trigg Furnace, Kentucky, July 6, 2013

This EF0 tornado ran 0.9 miles across Trigg County on July 6, 2013, touching down at 7:50 PM CDT and reaching 50 yards wide. It killed nobody, and did $5,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mphthis tornado

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 mph

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
EF0
Date
July 6, 2013
Touchdown
7:50 PM CDT (00:50 UTC)
Lifted
7:51 PM CDT (00:51 UTC)
On the ground
1 minutes
Path length
0.9 miles (1.4 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$5,000
County
Trigg County
Touchdown point
36.852, -87.931
Lift-off point
36.856, -87.915
Record number
1307061850-01

The damage survey

2 damage points were recorded along this path by NWS PAH, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 70 mph.

  • A trained spotter witnessed a tornado move into Lake Barkley State Resort Park. Large tree limbs were blown onto power lines. Peak winds were estimated near 65 mph.
  • The tornado moved over water causing no damage.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

What the Weather Service recorded

A complex of thunderstorms developed underneath a pocket of cold air associated with a low in the upper levels of the atmosphere. At the surface, southerly winds on the back side of high pressure over the southern Appalachians brought warmth and moisture. A few of the storms produced severe weather. The complex of thunderstorms moved slowly, causing very heavy rainfall and flash flooding over parts of the Lakes region.

A trained spotter witnessed a tornado move into Lake Barkley State Resort Park. Large tree limbs were blown onto power lines. Peak winds were estimated near 65 mph.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

24 minutes of warning. NWS PAH issued a tornado warning for this county at 00:26 UTC, 24 minutes before the tornado touched down, in force until 01:00 UTC.

Issued (UTC)ExpiredProductOffice
00:26 UTC01:00 UTCTornado WarningPAH

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a General Thunderstorms Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:50 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Nashville Metro, TN (KBNA), 00:00Z

0.8 hours before the tornado, 143 km from the path. July 7, 2013.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 2013-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 115 joules per kilogram, CIN -41, lifted condensation level 686 meters above ground. Wind barbs in knots down the right edge.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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Nashville Metro, TN at 00:00Z on 2013-07-07The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 68 square meters per square second, 0 to 6 km bulk shear 42 knots.19395878Sfc1 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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
115 J/kg
Mixed-layer CIN
-41 J/kg
Surface CAPE
475 J/kg
Mixed-layer LCL
686 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
5.8 K/km

Open this sounding in Storm Lab

Nashville Metro, TN (KBNA), 12:00Z

11.2 hours after it, 143 km from the path. July 7, 2013.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 12:00Z on 2013-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 725 joules per kilogram, CIN -26, lifted condensation level 628 meters above ground. Wind barbs in knots down the right edge.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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Nashville Metro, TN at 12:00Z on 2013-07-07The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 29 square meters per square second, 0 to 6 km bulk shear 26 knots.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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
725 J/kg
Mixed-layer CIN
-26 J/kg
Surface CAPE
1 J/kg
Mixed-layer LCL
628 m above ground
0-6 km bulk shear
26 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
40 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0
0-3 km lapse rate
4.3 K/km

Open this sounding in Storm Lab

The surface observations

Fort Campbell (Aaf) (HOP), 43 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:58 UTC78.4469.26130° 10 kt1017.3
23:58 UTC77.5469.26120° 11 kt1017.3
00:58 UTC74.1270.7110° 7 kt1017.9
01:58 UTC7370.8880° 6 kt1018.6
02:28 UTC71.669.8270° 17 kt191020TS
02:32 UTC71.668240° 21 kt261020.3TS
02:33 UTC71.668240° 21 kt261020.3-TSRA BR
02:35 UTC69.868230° 18 kt261020.7TSRA BR
02:36 UTC69.868220° 18 kt261020.7TSRA BR
02:37 UTC6868220° 16 kt261020.7+TSRA BR
02:38 UTC6868220° 12 kt261020.3+TSRA BR
02:40 UTC66.266.2220° 9 kt261020.3+TSRA BR
02:41 UTC66.266.2210° 7 kt261020+TSRA BR
02:42 UTC66.266.2210° 4 kt261020+TSRA BR

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Ft Campbell radar (KHPX), 58 km away, was scanning. The volume nearest the touchdown began at 00:48 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
23:55 UTCHAIL 0.882 E Calvert CityMarshall, KY
23:59 UTCFLASH FLOOD2 E Calvert CityMarshall, KY
00:50 UTCTORNADO4 W CadizTrigg, KY
03:15 UTCFLASH FLOOD1 N HazelCalloway, KYA SECTION OF U.S. 641 WAS CLOSED AND SEVERAL MOTORISTS WERE STRANDED AND HAD TO BE HELPED FROM THEIR VEHICLES.
03:15 UTCFLASH FLOODMurrayCalloway, KYSOUTH OF MURRAY ON HIGHWAY 121...A SECTION OF THE ROAD WAS CLOSED BETWEEM MILE MARKER 3 AND 4.
03:20 UTCFLASH FLOODMurrayCalloway, KYJUST SOUTH OF THE CITY LIMITS...SEVERAL SECONDARY ROADS HAD HIGH WATER SIGNS OUT AND TRAFFIC WAS NOT ALLOWED THROUGH. THIS INCLUDES COUNTY ROAD 1497 AND MURRAY-PARIS ROAD.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2013 tornado in KentuckyEvery tornado in Kentucky since 1950Warnings in force in Kentucky nowThe forecast where you are

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.