Tornadoes · United States · Tennessee · 2020
EF0 tornado, Vervilla, Tennessee, August 28, 2020
This EF0 tornado ran 1.5 miles across Warren County on August 28, 2020, touching down at 5:28 PM CDT and reaching 65 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.
EF065 to 85 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- August 28, 2020
- Touchdown
- 5:28 PM CDT (22:28 UTC)
- Lifted
- 5:31 PM CDT (22:31 UTC)
- On the ground
- 3 minutes
- Path length
- 1.5 miles (2.5 km)
- Path width
- 65 yards (59 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $5,000
- County
- Warren County
- Touchdown point
- 35.553, -85.903
- Lift-off point
- 35.565, -85.880
- Record number
- 2008281628-01
The damage survey
6 damage points were recorded along this path by NWS OHX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 65 mph.
- Very old shed was destroyed
- Corn blow down in convergent narrow path
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
After making landfall in southwest Louisiana on Wednesday, August 26, 2020, Hurricane Laura moved northward into Arkansas and weakened to a tropical storm on Thursday, August 27, then traveled eastward across Tennessee and Kentucky and weakened further to a tropical depression on Friday, August 28. The system brought numerous showers and thunderstorms to Middle Tennessee, some of which became severe and produced several reports of damaging winds along with two weak tornadoes. Rainfall totals across the area ranged from 1 to 3 inches.
A damage survey by Warren County Emergency Management along with video by nearby residents indicate a brief and weak EF-0 tornado intermittently touched down in extreme southwest Warren County between Morrison and Viola. One barn sustained significant damage on Cecil Laxson Road and several trees were blown down along the roadway and in adjacent orchards. Another small barn was destroyed on Fred Hoover Road with a damage path noted through adjacent corn fields. This is the first known tornado to occur in Warren County in the month of August.
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. One was issued for the county at another hour that day.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 18:07 UTC | 20:47 UTC | Tornado Watch | OHX |
| 22:45 UTC | 23:00 UTC | Tornado Warning | OHX |
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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 20:00 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
10.5 hours before the tornado, 90 km from the path. August 28, 2020.
- Mixed-layer CAPE
- 598 J/kg
- Mixed-layer CIN
- -32 J/kg
- Surface CAPE
- 1298 J/kg
- Mixed-layer LCL
- 737 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 152 m²/s²
- 0-3 km storm-relative helicity
- 138 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 3.7
- 0-3 km lapse rate
- 5.0 K/km
Nashville Metro, TN (KBNA), 00:00Z
1.5 hours after it, 90 km from the path. August 29, 2020.
- Mixed-layer CAPE
- 11 J/kg
- Mixed-layer CIN
- -71 J/kg
- Surface CAPE
- 154 J/kg
- Mixed-layer LCL
- 671 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 188 m²/s²
- 0-3 km storm-relative helicity
- 202 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
- 0-3 km lapse rate
- 4.4 K/km
The radar
The Northeast Alabama radar (KHTX), 72 km away, was scanning. The volume nearest the touchdown began at 22:26 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) | Report | Where | County | Remark |
|---|---|---|---|---|
| 22:27 UTC | TSTM WND DMG | 3 Wnw Viola | Warren, TN | REPORT OF BARN DESTROYED ON CECIL LAXSON RD. |
| 22:27 UTC | TORNADO | 3 Wnw Viola | Warren, TN | A DAMAGE SURVEY BY WARREN COUNTY EMA ALONG WITH VIDEO BY NEARBY RESIDENTS INDICATE A VERY BRIEF WEAK EF-0 TORNADO TOUCHED DOWN IN EXTREME SOUTHWEST WARREN COUNTY BETWEEN MORRISON AND VIOLA ALONG CECIL LAXSON ROAD. ONE BA |
| 22:28 UTC | TORNADO | 3 Wnw Viola | Warren, TN | UPDATED INFO...A DAMAGE SURVEY BY WARREN COUNTY EMERGENCY MANAGEMENT ALONG WITH VIDEO BY NEARBY RESIDENTS INDICATE A BRIEF WEAK EF-0 TORNADO INTERMITTENTLY TOUCHED DOWN IN SOUTHWEST WARREN COUNTY BETWEEN MORRISON AND VIO |
| 23:10 UTC | TSTM WND DMG | 9 Ene Mcminnville | Warren, TN | LARGE TREE DOWN BLOCKING ROAD AT 1621 COPENHAVER ROAD. TIME ESTIMATED. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2020 tornado in TennesseeEvery tornado in Tennessee since 1950Warnings in force in Tennessee nowThe forecast where you are
The other tornadoes of August 28, 2020
12 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| August 28 | 1:26 AM CDT | Unrated | Kingsbury, SD | 0.4 | 25 | |||
| August 28 | 1:27 AM CDT | EF1 | Kingsbury, SD | 0.6 | 25 | $75,000 | ||
| August 28 | 2:08 AM CDT | EF0 | Deuel, SD | 0.1 | 50 | |||
| August 28 | 2:09 AM CDT | EF0 | Deuel, SD | 0.2 | 20 | |||
| August 28 | 2:09 AM CDT | EF0 | Deuel, SD | 0.7 | 30 | |||
| August 28 | 2:11 AM CDT | EF1 | Deuel, SD | 0.9 | 40 | |||
| August 28 | 6:33 AM CDT | EF0 | Lafayette, MS | 1.1 | 50 | |||
| August 28 | 4:02 PM CDT | EF1 | Winston, AL | 8.8 | 325 | |||
| August 28 | 4:36 PM CDT | EF1 | Winston, AL | 2.6 | 100 | |||
| August 28 | 5:27 PM CDT | EF1 | Cullman, AL | 5.6 | 115 | |||
| August 28 | 5:58 PM CDT | EF0 | Morgan, AL | 0.2 | 40 | |||
| August 28 | 7:24 PM CDT | EF0 | Putnam, TN | 2.4 | 50 | $15,000 |
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.