Tornadoes · United States · Oklahoma · 2019

Unrated tornado, Lone Wolf, Oklahoma, May 20, 2019

This Unrated tornado ran 0.5 miles across Kiowa County on May 20, 2019, touching down at 6:14 PM CDT and reaching 30 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 20, 2019
Touchdown
6:14 PM CDT (23:14 UTC)
Lifted
6:15 PM CDT (23:15 UTC)
On the ground
1 minutes
Path length
0.5 miles (0.8 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
Kiowa County
Touchdown point
35.044, -99.223
Lift-off point
35.044, -99.223
Record number
1905201714-01

What the Weather Service recorded

An extremely unstable environment led to widespread severe weather across Texas and Oklahoma on the 20th into the morning of the 21st.

Multiple storm spotters and storm chasers observed a brief tornado estimated to be about 4 miles north-northeast of Lone Wolf. No damage was reported.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

28 minutes of warning. NWS OUN issued a tornado warning for this county at 22:46 UTC, 28 minutes before the tornado touched down, in force until 23:30 UTC.

The county was under a tornado watch, issued at 18:37 UTC and running to 03:00 UTC.

Issued (UTC)ExpiredProductOffice
12:00 UTC18:00 UTCFlood WatchOUN
18:37 UTC03:00 UTCTornado WatchOUN
22:21 UTC23:00 UTCTornado WarningOUN
22:46 UTC23:30 UTCTornado WarningOUN
22:57 UTC23:45 UTCSevere Thunderstorm WarningOUN
23:01 UTC23:31 UTCTornado WarningOUN
23:35 UTC02:30 UTCFlood AdvisoryOUN
23:44 UTC00:30 UTCSevere Thunderstorm WarningOUN
00:15 UTC03:15 UTCFlash Flood WarningOUN
03:14 UTC12:15 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 High Risk, with a 0.45 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 20:02 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), 12:00Z

11.2 hours before the tornado, 167 km from the path. May 20, 2019.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 12:00Z on 2019-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 79 joules per kilogram, CIN -389, lifted condensation level 1022 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 12:00Z on 2019-05-20The 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 260 square meters per square second, 0 to 6 km bulk shear 44 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
79 J/kg
Mixed-layer CIN
-389 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1022 m above ground
0-6 km bulk shear
44 kt
0-1 km bulk shear
25 kt
0-1 km storm-relative helicity
260 m²/s²
0-3 km storm-relative helicity
302 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.8
0-3 km lapse rate
3.6 K/km

Open this sounding in Storm Lab

Norman, OK (KOUN), 00:00Z

0.8 hours after it, 167 km from the path. May 21, 2019.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 00:00Z on 2019-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 3095 joules per kilogram, CIN -2, lifted condensation level 733 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 2019-05-21The 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 420 square meters per square second, 0 to 6 km bulk shear 65 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
3095 J/kg
Mixed-layer CIN
-2 J/kg
Surface CAPE
4175 J/kg
Mixed-layer LCL
733 m above ground
0-6 km bulk shear
65 kt
0-1 km bulk shear
42 kt
0-1 km storm-relative helicity
420 m²/s²
0-3 km storm-relative helicity
523 m²/s²
Significant tornado parameter
10.8
Supercell composite
43.6
0-3 km lapse rate
5.3 K/km

Open this sounding in Storm Lab

The radar

The Altus AFB radar (KFDR), 79 km away, was scanning. The volume nearest the touchdown began at 23:13 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
22:12 UTCTORNADO8 Sw MangumGreer, OK
22:54 UTCHAIL 11 S GraniteGreer, OK
22:56 UTCFLASH FLOOD4 Wnw Lone WolfKiowa, OKROAD COVERED IN WATER, ESTIMATED 5 INCHES ABOVE ROAD, ESTIMATE ONLY, NOT PASSIBLE.
23:47 UTCTSTM WND GST 772 Wsw Burns FlatWashita, OKAT CLINTON/SHERMAN AIRPORT.
00:00 UTCTSTM WND GST 594 Wnw BessieWashita, OK
01:52 UTCFLASH FLOODCordellWashita, OKSEVERAL ROADWAYS BEING CLOSED DUE TO FLASH FLOODING, INCLUDING HWY 183 AND MARKET.

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 20, 2019

38 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 209:50 AM MSTEF0Coconino, AZ1.010
May 202:05 PM CDTUnratedDickens, TX1.030
May 203:00 PM CDTUnratedCottle, TX0.210
May 203:01 PM CDTEF0Cottle, TX1.920
May 203:29 PM CDTEF0Collingsworth, TX0.350
May 203:31 PM CDTUnratedKingfisher, OK0.540
May 203:43 PM CDTUnratedKingfisher, OK3.7150
May 203:46 PM CDTUnratedKingfisher, OK0.550
May 203:50 PM CDTEF1Logan, OK6.070$3,000
May 203:54 PM CDTUnratedLogan, OK1.040
May 204:08 PM CDTEF1Logan, OK0.340$1,000
May 204:14 PM CDTEF1Cherokee, KS2.2440$25,000
May 204:23 PM CDTEF1Noble, OK to KS, MO3.0100$75,000
May 204:23 PM CDTEF1Crawford, KS to MO10.71,200$1.1 million
May 204:36 PM CDTEF0Kingfisher, OK0.120
May 204:37 PM CDTUnratedHarmon, OK0.550
May 204:38 PM CDTEF0Kingfisher, OK0.120
May 204:45 PM CDTUnratedHarmon, OK0.330
May 204:55 PM CDTEF0Kingfisher, OK1.420
May 204:59 PM CDTUnratedHarmon, OK0.120
May 205:05 PM CDTEF1Noble, OK7.7100$75,000
May 205:09 PM CDTEF0Logan, OK0.350$1,000
May 205:12 PM CDTEF2Greer, OK11.01,200$300,000
May 205:23 PM CDTEF3Ector, TX5.8225$400,000
May 205:38 PM CDTUnratedNoble, OK0.230
May 205:38 PM CDTUnratedGreer, OK0.240
May 206:48 PM EDTEF0Lee, FL0.130$25,000
May 206:45 PM CDTUnratedJasper, MO0.250
May 206:47 PM CDTUnratedDickens, TX3.4300
May 206:52 PM CDTEF2Midland, TX6.61502$250,000
May 209:05 PM CDTEF0Tulsa, OK0.5100$2,000
May 209:08 PM CDTUnratedFisher, TX0.030
May 2010:01 PM CDTEF1Okmulgee, OK4.4450$25,000
May 2010:09 PM CDTEF0Wagoner, OK0.875
May 2010:29 PM CDTUnratedHaskell, TX0.030
May 2010:29 PM CDTEF2Cherokee, OK21.02,7001$950,000
May 2010:35 PM CDTEF1Mayes, OK3.61,100$10,000
May 2010:54 PM CDTEF1Delaware, OK6.9600$50,000

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.