Tornadoes · United States · Oklahoma · 2019

Unrated tornado, Butler to Moorewood, Oklahoma, May 7, 2019

From Butler to Moorewood, this Unrated tornado ran 2.0 miles across Custer County on May 7, 2019, touching down at 8:32 PM CDT and reaching 50 yards wide. It killed nobody.

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 mph

    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. Unratedthis tornado

    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
Unrated
Date
May 7, 2019
Touchdown
8:32 PM CDT (01:32 UTC)
Lifted
8:36 PM CDT (01:36 UTC)
On the ground
4 minutes
Path length
2.0 miles (3.2 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Custer County
Touchdown point
35.773, -99.181
Lift-off point
35.801, -99.185
Record number
1905071932-01

What the Weather Service recorded

Numerous supercell storms were followed by a large line of thunderstorms that produced severe weather on the evening and overnight of the 7th into the 8th.

Two storm chasers observed a tornado in a rural area of northern Custer County north of Butler. No damage was reported and the tornado path is estimated.

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.

The county was under a tornado watch, issued at 22:38 UTC and running to 02:19 UTC.

Issued (UTC)ExpiredProductOffice
22:38 UTC02:19 UTCTornado WatchOUN
23:39 UTC00:30 UTCSevere Thunderstorm WarningOUN
00:00 UTC15:00 UTCFlood WatchOUN
00:22 UTC00:36 UTCSevere Thunderstorm WarningOUN
00:39 UTC01:30 UTCSevere Thunderstorm WarningOUN
01:21 UTC02:00 UTCSevere Thunderstorm WarningOUN
01:35 UTC01:49 UTCTornado WarningOUN
01:57 UTC02:45 UTCSevere Thunderstorm WarningOUN
02:19 UTC07:40 UTCTornado WatchOUN
04:00 UTC07:00 UTCFlood AdvisoryOUN
04:27 UTC05:15 UTCSevere Thunderstorm WarningOUN
05:01 UTC08:00 UTCFlash Flood WarningOUN
05:07 UTC08:15 UTCFlood AdvisoryOUN
05:11 UTC06:00 UTCSevere Thunderstorm WarningOUN
05:58 UTC08:00 UTCFlash Flood WarningOUN
08:02 UTC12:00 UTCFlood AdvisoryOUN
12:10 UTC12:52 UTCFlood WarningOUN
14:10 UTC08:31 UTCFlood WarningOUN

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 Enhanced Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 01:03 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.

Norman, OK (KOUN), 00:00Z

1.5 hours before the tornado, 173 km from the path. May 8, 2019.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 00:00Z on 2019-05-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1355 joules per kilogram, CIN -11, lifted condensation level 1174 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 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, Norman, OK at 00:00Z on 2019-05-08The 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 87 square meters per square second, 0 to 6 km bulk shear 32 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
1355 J/kg
Mixed-layer CIN
-11 J/kg
Surface CAPE
3231 J/kg
Mixed-layer LCL
1174 m above ground
0-6 km bulk shear
32 kt
0-1 km bulk shear
17 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
152 m²/s²
Significant tornado parameter
0.5
Supercell composite
5.9
0-3 km lapse rate
7.3 K/km

Open this sounding in Storm Lab

Norman, OK (KOUN), 12:00Z

10.5 hours after it, 173 km from the path. May 8, 2019.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 12:00Z on 2019-05-08Temperature 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 -40372, lifted condensation level 1045 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, Norman, OK at 12:00Z on 2019-05-08The 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 -192 square meters per square second, 0 to 6 km bulk shear 46 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
0 J/kg
Mixed-layer CIN
-40372 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1045 m above ground
0-6 km bulk shear
46 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
-192 m²/s²
0-3 km storm-relative helicity
7 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.8 K/km

Open this sounding in Storm Lab

The radar

The Vance AFB radar (KVNX), 142 km away, was scanning. The volume nearest the touchdown began at 01:31 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
01:33 UTCHAIL 110 W ViciEllis, OKTWITTER PHOTO IN MESSAGES.

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

This ground now

The live radar over the trackEvery 2019 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

The other tornadoes of May 7, 2019

22 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 73:36 PM CDTUnratedHutchinson, TX2.9100
May 74:27 PM CDTUnratedHale, TX0.030
May 74:48 PM CDTEF0Pecos, TX2.0200
May 74:49 PM CDTEF0Hutchinson, TX0.130
May 74:50 PM CDTEF0Ochiltree, TX0.020
May 74:00 PM MDTEF0Twin Falls, ID1.510
May 75:11 PM CDTUnratedSwisher, TX1.5600
May 75:16 PM CDTEF0Hutchinson, TX5.450
May 75:56 PM CDTUnratedSwisher, TX5.3150
May 76:27 PM CDTEF0Armstrong, TX11.5100
May 76:56 PM CDTEF0Lipscomb, TX0.120
May 77:25 PM CDTEF0Donley, TX1.173
May 77:35 PM CDTEF0Pecos, TX4.1450
May 77:48 PM CDTEF0Donley, TX4.2500
May 78:12 PM CDTUnratedBeckham, OK2.0100
May 710:10 PM CDTUnratedBeckham, OK0.530
May 711:19 PM CDTEF0Butler, KS1.9100
May 711:23 PM CDTEF2Kiowa, OK3.7300$75,000
May 711:32 PM CDTEF2Washita, OK8.8400$120,000
May 711:46 PM CDTUnratedWashita, OK0.540
May 711:57 PM CDTEF1Kay, OK2.160$25,000
May 712:27 AM CDTUnratedKiowa, OK0.530

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.