Tornadoes · United States · Texas · 2017

Unrated tornado, Lehman, Texas, May 9, 2017

This Unrated tornado ran 0.0 miles across Cochran County on May 9, 2017, touching down at 9:31 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 9, 2017
Touchdown
9:31 PM CDT (02:31 UTC)
Lifted
9:32 PM CDT (02:32 UTC)
On the ground
1 minutes
Path length
0.0 miles (0.0 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
Cochran County
Touchdown point
33.490, -102.860
Lift-off point
33.490, -102.860
Record number
1705092031-01

What the Weather Service recorded

Scattered supercell thunderstorms developed in the High Plains of eastern New Mexico this afternoon, before spreading northeast into the western South Plains of Texas accompanied by very large hail at times. Some of these storms acquired low-level rotation and resulted in small, brief tornadoes over open land. Also, repeated storms in portions of Bailey County resulted in several inches of rain through the evening. The ensuing flash flood forced the Texas Department of Transportation to close some rural roads, mainly south of Muleshoe (Bailey County) where water and mud flowing over roads made travel impossible.

A storm chaser observed a rope tornado illuminated by lightning.

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

The warnings

2 minutes of warning. NWS LUB issued a tornado warning for this county at 02:29 UTC, 2 minutes before the tornado touched down, in force until 03:00 UTC.

The county was under a tornado watch, issued at 20:25 UTC and running to 03:59 UTC.

Issued (UTC)ExpiredProductOffice
20:25 UTC03:59 UTCTornado WatchLUB
23:17 UTC00:00 UTCSevere Thunderstorm WarningLUB
23:56 UTC00:30 UTCTornado WarningLUB
00:11 UTC01:15 UTCFlood AdvisoryLUB
00:30 UTC00:42 UTCSevere Thunderstorm WarningLUB
01:54 UTC02:30 UTCTornado WarningLUB
02:15 UTC03:15 UTCFlood AdvisoryLUB
02:29 UTC03:00 UTCTornado WarningLUB
02:58 UTC03:18 UTCTornado WarningLUB
03:59 UTC10:24 UTCSevere Thunderstorm WatchLUB
07:49 UTC08:45 UTCFlood AdvisoryLUB

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 00:56 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.

Midland Regional, TX (KMAF), 00:00Z

2.5 hours before the tornado, 182 km from the path. May 10, 2017.

Skew-T log-pSkew-T log-p diagram, Midland Regional, TX at 00:00Z on 2017-05-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 929 joules per kilogram, CIN -88, lifted condensation level 1712 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, Midland Regional, TX at 00:00Z on 2017-05-10The 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 66 square meters per square second, 0 to 6 km bulk shear 56 knots.1939587897117Sfc1 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
929 J/kg
Mixed-layer CIN
-88 J/kg
Surface CAPE
2389 J/kg
Mixed-layer LCL
1712 m above ground
0-6 km bulk shear
56 kt
0-1 km bulk shear
6 kt
0-1 km storm-relative helicity
66 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
0.1
Supercell composite
2.5
0-3 km lapse rate
8.6 K/km

Open this sounding in Storm Lab

Midland Regional, TX (KMAF), 12:00Z

9.5 hours after it, 182 km from the path. May 10, 2017.

Skew-T log-pSkew-T log-p diagram, Midland Regional, TX at 12:00Z on 2017-05-10Temperature 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 -83035, lifted condensation level 2517 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, Midland Regional, TX at 12:00Z on 2017-05-10The 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 -77 square meters per square second, 0 to 6 km bulk shear 53 knots.1939587897117Sfc1 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
-83035 J/kg
Surface CAPE
117 J/kg
Mixed-layer LCL
2517 m above ground
0-6 km bulk shear
53 kt
0-1 km bulk shear
16 kt
0-1 km storm-relative helicity
-77 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4
0-3 km lapse rate
5.1 K/km

Open this sounding in Storm Lab

The surface observations

Seminole (GNC), 93 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
00:35 UTC73.660.8120° 19 kt251009.1
00:55 UTC73.460.8120° 17 kt241009.1
01:15 UTC71.660.8120° 16 kt241009.1
01:35 UTC71.259.7130° 19 kt241009.1
01:55 UTC7060140° 18 kt231009.1
02:15 UTC7258140° 18 kt221009.8
02:35 UTC71.658.5140° 17 kt251009.8
02:55 UTC70.559.5140° 15 kt201010.2
03:15 UTC69.460130° 14 kt181010.5
03:35 UTC69.460.3140° 15 kt231010.5
03:55 UTC68.760.4140° 17 kt211010.5
04:15 UTC68.460.4140° 15 kt1010.5

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Lubbock radar (KLBB), 99 km away, was scanning. The volume nearest the touchdown began at 02:33 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
00:30 UTCHAIL 1.255 S EnochsCochran, TX
00:30 UTCHAIL 2.54 S EnochsCochran, TX
00:46 UTCTORNADO5 Sw BulaBailey, TXBRIEF TORNADO EAST OF ENOCHS. SEVERAL PHOTOS BY STORM CHASERS VI SM.
01:25 UTCFLOOD3 Ne EnochsBailey, TXROAD FLOODED ALONG WITH HAIL SEVERAL INCHES DEEP.
02:32 UTCTORNADO10 Ssw LehmanCochran, TXROPE TORNADO JUST WEST OF LOCATION... WEST OF 214.

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

This ground now

The live radar over the trackEvery 2017 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

The other tornadoes of May 9, 2017

7 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 912:15 PM MDTEF0Torrance, NM4.940
May 912:25 PM MDTEF0Santa Fe, NM0.340
May 912:55 PM MDTEF0Lincoln, NM0.130
May 94:00 PM MDTEF0Mora, NM3.550
May 96:11 PM MDTUnratedKiowa, CO1.250
May 97:46 PM CDTUnratedBailey, TX0.020
May 98:45 PM CDTUnratedLamb, TX0.015

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.