Tornadoes · United States · Tennessee · 2009

EF0 tornado, Mc Minnville Arpt Fl to Oakland, Tennessee, September 7, 2009

From Mc Minnville Arpt Fl to Oakland, this EF0 tornado ran 2.0 miles across Warren County on September 7, 2009, touching down at 6:58 PM CDT and reaching 50 yards wide. It killed nobody, and did $25,000 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
September 7, 2009
Touchdown
6:58 PM CDT (23:58 UTC)
Lifted
7:02 PM CDT (00:02 UTC)
On the ground
4 minutes
Path length
2.0 miles (3.3 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$25,000
Crop damage
$1,000
County
Warren County
Touchdown point
35.694, -85.837
Lift-off point
35.677, -85.806
Record number
0909071758-01

What the Weather Service recorded

As upper level disturbances rotated around the eastern periphery of an upper level trough positioned across the mid state, and southwesterly low level flow ushered in deep low level moisture, severe thunderstorms developed during the mid afternoon through evening hours, mainly across the eastern half of Middle Tennessee. These severe thunderstorms produced thunderstorm wind damage, large hail, heavy rainfall, and a tornado in Warren County.

Large trees were snapped and uprooted. Roof damage was reported to a trailer and a car wash. Siding was peeled back off homes on Laws Road.

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

The warnings

14 minutes of warning. NWS OHX issued a tornado warning for this county at 23:44 UTC, 14 minutes before the tornado touched down, in force until 00:15 UTC.

Issued (UTC)ExpiredProductOffice
23:22 UTC23:45 UTCSevere Thunderstorm WarningOHX
23:44 UTC00:15 UTCTornado WarningOHX

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. The outlook in force was issued at 19:33 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), 12:00Z

12.0 hours before the tornado, 86 km from the path. September 7, 2009.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 12:00Z on 2009-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1841 joules per kilogram, CIN -20, lifted condensation level 673 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 2009-09-07The 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 82 square meters per square second, 0 to 6 km bulk shear 21 knots.1939Sfc1 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
1841 J/kg
Mixed-layer CIN
-20 J/kg
Surface CAPE
1027 J/kg
Mixed-layer LCL
673 m above ground
0-6 km bulk shear
21 kt
0-1 km bulk shear
15 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
74 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.9
0-3 km lapse rate
5.7 K/km

Open this sounding in Storm Lab

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

0.0 hours before the tornado, 86 km from the path. September 8, 2009.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 2009-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2090 joules per kilogram, CIN -23, lifted condensation level 1043 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 2009-09-08The 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 39 square meters per square second, 0 to 6 km bulk shear 27 knots.1939Sfc1 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
2090 J/kg
Mixed-layer CIN
-23 J/kg
Surface CAPE
2802 J/kg
Mixed-layer LCL
1043 m above ground
0-6 km bulk shear
27 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
39 m²/s²
0-3 km storm-relative helicity
23 m²/s²
Significant tornado parameter
0.3
Supercell composite
1.6
0-3 km lapse rate
7.7 K/km

Open this sounding in Storm Lab

The radar

The Northeast Alabama radar (KHTX), 87 km away, was scanning. The volume nearest the touchdown began at 23:58 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
22:28 UTCHAIL 1WatertownWilson, TNQUARTER SIZED HAIL FELL FOR 5 MINUTES IN WATERTOWN. SPOTTER ALSO REPORTED LARGE LIMBS BLOWN DOWN.
23:28 UTCHAIL 0.885 Sse SmithvilleDekalb, TNRESIDENT ON JACOBS-PILLAR ROAD REPORTED NICKEL SIZE HAIL.
23:42 UTCTSTM WND DMG6 Sw SmithvilleDekalb, TNTREES BLOWN DOWN ON BANKS-PISGAH ROAD.
23:57 UTCTORNADO3 Nw McminnvilleWarren, TNLARGE TREES SNAPPED AND UPROOTED...TRAILER ROOF PEELED BACK...SIDING PEELED OFF HOMES ON LAWS ROAD.
00:00 UTCTSTM WND DMG3 Nw McminnvilleWarren, TNLARGE TREES SNAPPED AND UPROOTED...TRAILER ROOF PEELED BACK...SIDING PEELED OFF HOMES ON LAWS ROAD. NWS WILL SURVEY DAMAGE WEDNESDAY MORNING.
00:01 UTCFUNNEL CLOUD1 Sw McminnvilleWarren, TNRESIDENT CALLED S.O. AND REPORTED A FUNNEL CLOUD ON VERVILLA ROAD JUST SOUTHWEST OF THE CITY OF MCMINNVILLE.

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

This ground now

The live radar over the trackEvery 2009 tornado in TennesseeEvery tornado in Tennessee since 1950Warnings in force in Tennessee 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.