Tornadoes · United States · Illinois · 2000
F1 tornado, Oconee, Illinois, June 20, 2000
This F1 tornado ran 24.0 miles across Shelby County on June 20, 2000, touching down at 2:32 PM CDT and reaching 300 yards wide. It killed nobody and injured 1, and did $70,000 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
- June 20, 2000
- Touchdown
- 2:32 PM CDT (19:32 UTC)
- Path length
- 24.0 miles (38.6 km)
- Path width
- 300 yards (274 m)
- Deaths
- 0
- Injuries
- 1
- Property damage
- $70,000
- County
- Shelby County
- Touchdown point
- 39.280, -89.120
- Lift-off point
- 39.380, -88.700
- Record number
- 983
What the Weather Service recorded
The tornado first briefly touched down in the Oconee area where it blew down several large trees and tree limbs. The tornado then appeared to lift and move east-northeast across southern Shelby county, occasionally touching the ground in a number of places. The most significant touchdowns were found in two areas. The first was about 4 miles south of Tower Hill, where the track extended from 4.5 miles south-southwest of Tower Hill to 4 miles south-southeast of Tower Hill. Damage to trees, a grain bin, a garage and a grain auger were found in the area. The second significant touchdown started 4 miles south-southeast of Shelbyville. Even in this area, visual sightings by residents indicated that the tornado was not on the ground all the time. Damage in this area was the most substantial, with damage to several garages, as well as outbuildings destroyed and numerous trees uprooted. One women sustained minor cuts from flying glass.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
21 minutes of warning. NWS ILX issued a tornado warning for this county at 19:11 UTC, 21 minutes before the tornado touched down, in force until 20:00 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 18:24 UTC | 19:15 UTC | Severe Thunderstorm Warning | ILX |
| 19:11 UTC | 20:00 UTC | Tornado Warning | ILX |
| 19:48 UTC | 20:30 UTC | Tornado Warning | ILX |
| 20:30 UTC | 21:15 UTC | Tornado Warning | ILX |
| 01:47 UTC | 02:30 UTC | Severe Thunderstorm Warning | ILX |
| 03:08 UTC | 04:15 UTC | Severe Thunderstorm Warning | ILX |
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 15:29 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.
Lincoln, IL (KILX), 12:00Z
7.5 hours before the tornado, 95 km from the path. June 20, 2000.
- Mixed-layer CAPE
- 135 J/kg
- Mixed-layer CIN
- -82 J/kg
- Surface CAPE
- 532 J/kg
- Mixed-layer LCL
- 1033 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 216 m²/s²
- 0-3 km storm-relative helicity
- 234 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 2.2
- 0-3 km lapse rate
- 5.1 K/km
Lincoln, IL (KILX), 00:00Z
4.5 hours after it, 95 km from the path. June 21, 2000.
- Mixed-layer CAPE
- 831 J/kg
- Mixed-layer CIN
- -30 J/kg
- Surface CAPE
- 2788 J/kg
- Mixed-layer LCL
- 828 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 216 m²/s²
- 0-3 km storm-relative helicity
- 287 m²/s²
- Significant tornado parameter
- 1.0
- Supercell composite
- 15.3
- 0-3 km lapse rate
- 5.4 K/km
The surface observations
Decatur (DEC), 56 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 17:50 UTC | 80.6 | 71.6 | 200° 15 kt | 20 | 1012.2 | -RA |
| 18:50 UTC | 75.2 | 73.4 | 200° 10 kt | 1011.5 | TSRA BR | |
| 19:50 UTC | 75.2 | 73.4 | 160° 12 kt | 1010.8 | -RA BR | |
| 20:50 UTC | 75.2 | 73.4 | 190° 14 kt | 1011.2 |
From the Iowa Environmental Mesonet's archive of airport observations.
This ground now
The live radar over the trackEvery 2000 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are
The other tornadoes of June 20, 2000
11 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| June 20 | 2:40 PM CDT | F0 | Montgomery, IL | 10.3 | 50 | |||
| June 20 | 5:07 PM EDT | F0 | Manatee, FL | 1.0 | 10 | $30,000 | ||
| June 20 | 4:22 PM CDT | F0 | Lafayette, MO | 1.0 | 50 | $10,000 | ||
| June 20 | 4:40 PM CDT | F0 | Carroll, MO | 1.0 | 40 | |||
| June 20 | 6:55 PM CDT | F0 | Logan, IL | 0.3 | 100 | $20,000 | ||
| June 20 | 7:00 PM EST | F0 | Henry, IN | 0.1 | 30 | |||
| June 20 | 7:05 PM CDT | F0 | Ralls, MO | 1.0 | 70 | $10,000 | ||
| June 20 | 7:15 PM EST | F0 | Henry, IN | 0.1 | 30 | $50,000 | ||
| June 20 | 7:44 PM CDT | F0 | Sangamon, IL | 0.2 | 150 | $1,000 | ||
| June 20 | 9:20 PM EDT | F0 | Shelby, OH | 0.3 | 20 | $2,000 | ||
| June 20 | 9:08 PM CDT | F0 | Piatt, IL | 2.6 | 50 | $20,000 |
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.