Tornadoes · United States · Arkansas · 2001

F1 tornado, Vilonia, Arkansas, May 20, 2001

This F1 tornado ran 4.0 miles across Faulkner County on May 20, 2001, touching down at 11:42 PM CDT and reaching 100 yards wide. It killed nobody.

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.

  1. F040 to 72 mph

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

  2. F173 to 112 mphthis tornado

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

  3. 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.

  4. 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.

  5. F4207 to 260 mph

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

  6. 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.

  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
F1
Date
May 20, 2001
Touchdown
11:42 PM CDT (04:42 UTC)
Path length
4.0 miles (6.4 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
County
Faulkner County
Touchdown point
35.100, -92.200
Lift-off point
35.120, -92.130
Record number
182

What the Weather Service recorded

An F1 tornado touched down one and a half miles northeast of Vilonia. Along the path of the tornado, trees were blown down onto two houses. One house suffered crushing of the roof and a couple of the walls, while the other house had roof damage. Several other houses lost shingles off their roofs. In addition, a couple of sheds were blown away and a number of large trees were blown down. After traveling 4 miles, the tornado finally lifted a little more than 5 miles east-northeast of Vilonia.

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)ExpiredProductOffice
16:52 UTC17:25 UTCSevere Thunderstorm WarningLZK
23:25 UTC00:20 UTCTornado WarningLZK
04:00 UTC05:05 UTCSevere Thunderstorm WarningLZK

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 Moderate Risk. The outlook in force was issued at 00:57 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.

Little Rock, AR (KLZK), 00:00Z

4.7 hours before the tornado, 204 km from the path. May 21, 2001.

Skew-T log-pSkew-T log-p diagram, Little Rock, AR at 00:00Z on 2001-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2153 joules per kilogram, CIN -22, lifted condensation level 1093 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°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, Little Rock, AR at 00:00Z on 2001-05-21The 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 211 square meters per square second, 0 to 6 km bulk shear 50 knots.1939587897Sfc1 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
2153 J/kg
Mixed-layer CIN
-22 J/kg
Surface CAPE
2937 J/kg
Mixed-layer LCL
1093 m above ground
0-6 km bulk shear
50 kt
0-1 km bulk shear
23 kt
0-1 km storm-relative helicity
211 m²/s²
0-3 km storm-relative helicity
242 m²/s²
Significant tornado parameter
2.7
Supercell composite
13.2
0-3 km lapse rate
6.4 K/km

Open this sounding in Storm Lab

Little Rock, AR (KLZK), 12:00Z

7.3 hours after it, 204 km from the path. May 21, 2001.

Skew-T log-pSkew-T log-p diagram, Little Rock, AR at 12:00Z on 2001-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -14223, lifted condensation level 1393 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Little Rock, AR at 12:00Z on 2001-05-21The 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 -14 square meters per square second, 0 to 6 km bulk shear 45 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
0 J/kg
Mixed-layer CIN
-14223 J/kg
Surface CAPE
1 J/kg
Mixed-layer LCL
1393 m above ground
0-6 km bulk shear
45 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
-14 m²/s²
0-3 km storm-relative helicity
-112 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.9 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 2001 tornado in ArkansasEvery tornado in Arkansas since 1950Warnings in force in Arkansas nowThe forecast where you are

The other tornadoes of May 20, 2001

32 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 2012:10 PM CDTF1Cleburne, AR5.8150
May 204:20 PM CDTF2Hughes, OK11.0250$230,000
May 204:20 PM CDTF0Phillips, KS0.110
May 204:40 PM CDTF0Rooks, KS0.530$10,000
May 204:58 PM CDTF0Rooks, KS1.050$120,000
May 205:16 PM CDTF0Rooks, KS0.530
May 206:15 PM CDTF0Wilson, TX0.330$10,000
May 206:30 PM CDTF0Haskell, OK0.5200
May 206:30 PM CDTF0Osage, OK0.325
May 206:44 PM CDTF0Russell, KS0.555
May 206:47 PM CDTF0Russell, KS1.555
May 206:49 PM CDTF0Barton, KS3.0110
May 206:51 PM CDTF0Pontotoc, OK0.325
May 206:54 PM CDTF0Haskell, OK0.3150$3,000
May 206:58 PM CDTF0Pittsburg, OK0.3100
May 207:15 PM CDTF0Coal, OK0.1150
May 207:30 PM CDTF0Haskell, OK1.0100
May 207:37 PM CDTF0Latimer, OK0.325
May 207:40 PM CDTF0Coal, OK0.230
May 207:44 PM CDTF0Sedgwick, KS0.555
May 207:55 PM CDTF0White, AR0.120
May 207:55 PM CDTF0LeFlore, OK0.325
May 208:13 PM CDTF0Madison, AR0.325
May 208:14 PM CDTF0Stafford, KS0.230
May 208:20 PM CDTF0Stafford, KS1.350
May 208:25 PM CDTF0Carroll, AR0.325
May 208:29 PM CDTF0Sebastian, AR1.0100$10,000
May 208:30 PM CDTF0Newton, MO0.5200$10,000
May 208:50 PM CDTF1LeFlore, OK1.0200$1,000
May 208:51 PM CDTF0Franklin, AR0.325
May 208:10 PM MDTF0Hamilton, KS0.230
May 2010:35 PM CDTF0Reynolds, MO0.150

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.