Tornadoes · United States · Tennessee · 2004
F1 tornado, Weatherly Switch, Tennessee, May 31, 2004
This F1 tornado ran 7.5 miles across Bradley County on May 31, 2004, touching down at 3:30 AM EDT and reaching 60 yards wide. It killed nobody, and did $80,000 of property damage.
The rating scale
Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
F040 to 72 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
F2113 to 157 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.
F3158 to 206 mph
Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
F5261 to 318 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.
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
- F1
- Date
- May 31, 2004
- Touchdown
- 3:30 AM EDT (07:30 UTC)
- Path length
- 7.5 miles (12.1 km)
- Path width
- 60 yards (55 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $80,000
- County
- Bradley County
- Touchdown point
- 35.000, -84.920
- Lift-off point
- 35.050, -84.820
- Record number
- 110
What the Weather Service recorded
A tornado touched down at 330 am EDT near the intersection of Mitchell and Greenbrier Roads and moved east just north of Mitchell Road then near the intersections of Stone Reagan and Kincaid Roads. It then moved across Hughes Lake Road before turning northeast and ending near the intersection of Bucks Pocket and Spring Place Road. The path was generally 25 to 50 yards wide...however in a few locations it was as wide as 100 yards. The tornado damaged several structures and downed several trees along its path and was rated an F1 on the Fujita Scale.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 07:19 UTC | 08:15 UTC | Severe Thunderstorm Warning | MRX |
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 05:47 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.
Peachtre/Fal Fld, GA (KFFC), 00:00Z
7.5 hours before the tornado, 187 km from the path. May 31, 2004.
- Mixed-layer CAPE
- 1721 J/kg
- Mixed-layer CIN
- -10 J/kg
- Surface CAPE
- 2386 J/kg
- Mixed-layer LCL
- 1316 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 45 m²/s²
- 0-3 km storm-relative helicity
- 102 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 3.7
- 0-3 km lapse rate
- 6.5 K/km
Peachtre/Fal Fld, GA (KFFC), 12:00Z
4.5 hours after it, 187 km from the path. May 31, 2004.
- Mixed-layer CAPE
- 858 J/kg
- Mixed-layer CIN
- -21 J/kg
- Surface CAPE
- 1010 J/kg
- Mixed-layer LCL
- 630 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 192 m²/s²
- 0-3 km storm-relative helicity
- 208 m²/s²
- Significant tornado parameter
- 0.9
- Supercell composite
- 3.9
- 0-3 km lapse rate
- 5.7 K/km
The surface observations
Chattanooga/Lovell (CHA), 30 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 05:53 UTC | 79 | 71 | 5 kt | 1008.5 | ||
| 06:53 UTC | 79 | 71 | 190° 8 kt | 1008.1 | -RA | |
| 07:28 UTC | 75.2 | 69.8 | 270° 20 kt | 44 | 1009.1 | +RA SQ |
| 07:38 UTC | 69.8 | 64.4 | 270° 17 kt | 28 | 1009.5 | +TSRA |
| 07:45 UTC | 69.8 | 64.4 | 250° 12 kt | 23 | 1009.5 | TSRA BR |
| 07:53 UTC | 69 | 65 | 250° 10 kt | 1009.5 | -TSRA | |
| 07:57 UTC | 69.8 | 64.4 | 260° 12 kt | 1009.1 | -RA | |
| 08:02 UTC | 69.8 | 64.4 | 270° 13 kt | 18 | 1008.5 | -TSRA |
| 08:28 UTC | 69.8 | 64.4 | 250° 5 kt | 1009.5 | -RA | |
| 08:53 UTC | 69 | 65 | 220° 3 kt | 1009.1 | RA BR |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Northeast Alabama radar (KHTX), 111 km away, was scanning. The volume nearest the touchdown began at 07:31 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.
This ground now
The live radar over the trackEvery 2004 tornado in TennesseeEvery tornado in Tennessee since 1950Warnings in force in Tennessee nowThe forecast where you are
The other tornadoes of May 31, 2004
12 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 31 | 2:00 AM EDT | F0 | Owsley, KY | 0.1 | 366 | |||
| May 31 | 2:00 AM EDT | F0 | Jackson, KY | 0.1 | 25 | |||
| May 31 | 2:04 AM EDT | F0 | Breathitt, KY | 0.1 | 25 | |||
| May 31 | 2:05 AM EDT | F1 | Knox, KY | 0.1 | 63 | $50,000 | ||
| May 31 | 2:15 AM EDT | F1 | Knox, KY | 0.2 | 63 | $30,000 | ||
| May 31 | 1:17 AM CDT | F1 | Moore, TN | 6.0 | 150 | $10,000 | ||
| May 31 | 1:19 AM CDT | F1 | Bedford, TN | 0.8 | 150 | $20,000 | ||
| May 31 | 4:22 AM CDT | F0 | Jefferson, AL | 1.7 | 150 | $250,000 | ||
| May 31 | 4:29 AM CDT | F0 | Jefferson, AL | 4.2 | 150 | $500,000 | ||
| May 31 | 2:20 PM CDT | F0 | Geneva, AL | 0.2 | 50 | $10,000 | ||
| May 31 | 5:20 PM EDT | F1 | Saint Clair, MI | 1.5 | 80 | $50,000 | ||
| May 31 | 5:05 PM CDT | F0 | Houston, TX | 0.2 | 20 |
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.