Tornadoes · United States · Texas · 2018

Unrated tornado, Dimmitt Muni Arpt to Summerfield, Texas, October 7, 2018

From Dimmitt Muni Arpt to Summerfield, this Unrated tornado ran 8.7 miles across Castro County on October 7, 2018, touching down at 2:31 PM CDT and reaching 200 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
October 7, 2018
Touchdown
2:31 PM CDT (19:31 UTC)
Lifted
2:49 PM CDT (19:49 UTC)
On the ground
18 minutes
Path length
8.7 miles (13.9 km)
Path width
200 yards (183 m)
Deaths
0
Injuries
0
County
Castro County
Touchdown point
34.610, -102.390
Lift-off point
34.735, -102.382
Record number
1810071331-01

What the Weather Service recorded

A strong warm front lifted north across the South Plains early this afternoon before eventually intersecting a surface trough in the far southwest Texas Panhandle. As storms developed along the trough, they moved north and acquired strong low level rotation as they interacted with the warm front. One of these supercell storms produced a large cone tornado in far northwest Castro County that fortunately remained over farm land producing no known damage.

This tornado was initially reported to Castro County Police by a motorist near Dimmitt. With time, this initially small tornado grew into a large cone as it moved north at about 30 mph. No known damage accompanied this tornado as it remained over farm land.

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
13:00 UTC17:00 UTCDense Fog AdvisoryLUB
19:37 UTC20:00 UTCTornado WarningLUB
19:55 UTC05:00 UTCSevere Thunderstorm WatchLUB

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 Marginal Risk. The outlook in force was issued at 17:55 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.

Amarillo Airport, TX (KAMA), 12:00Z

7.5 hours before the tornado, 88 km from the path. October 7, 2018.

Skew-T log-pSkew-T log-p diagram, Amarillo Airport, TX at 12:00Z on 2018-10-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 259 joules per kilogram, CIN -102, lifted condensation level 507 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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, Amarillo Airport, TX at 12:00Z on 2018-10-07The 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 246 square meters per square second, 0 to 6 km bulk shear 22 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
259 J/kg
Mixed-layer CIN
-102 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
507 m above ground
0-6 km bulk shear
22 kt
0-1 km bulk shear
35 kt
0-1 km storm-relative helicity
246 m²/s²
0-3 km storm-relative helicity
275 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.9
0-3 km lapse rate
3.5 K/km

Open this sounding in Storm Lab

Amarillo Airport, TX (KAMA), 00:00Z

4.5 hours after it, 88 km from the path. October 8, 2018.

Skew-T log-pSkew-T log-p diagram, Amarillo Airport, TX at 00:00Z on 2018-10-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 415 joules per kilogram, CIN -32, lifted condensation level 696 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km-30°-20°-10°0°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, Amarillo Airport, TX at 00:00Z on 2018-10-08The 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 218 square meters per square second, 0 to 6 km bulk shear 44 knots.193958Sfc1 km3 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
415 J/kg
Mixed-layer CIN
-32 J/kg
Surface CAPE
499 J/kg
Mixed-layer LCL
696 m above ground
0-6 km bulk shear
44 kt
0-1 km bulk shear
27 kt
0-1 km storm-relative helicity
218 m²/s²
0-3 km storm-relative helicity
247 m²/s²
Significant tornado parameter
0.4
Supercell composite
2.2
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

The surface observations

Hereford (HRX), 21 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
17:35 UTC61.561.3160° 6 kt1012.9BR
17:55 UTC62.262170° 4 kt1012.9BR
18:15 UTC63.563170° 7 kt1012.9
18:35 UTC64.464160° 10 kt1012.5
18:55 UTC64.864.4140° 8 kt1011.9
19:15 UTC64.864.4140° 9 kt1011.2
19:35 UTC65.565150° 9 kt141010.8DZ
19:55 UTC65.765130° 7 kt1010.5RA
20:15 UTC66.666.2120° 10 kt1009.8+RA
20:35 UTC66.766.270° 7 kt161009.5+VCTSRA
20:55 UTC6867.580° 11 kt1008.8VCTS
21:15 UTC6766.4120° 14 kt181008.1TSRA

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

The radar

The Amarillo radar (KAMA), 88 km away, was scanning. The volume nearest the touchdown began at 19:30 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
19:31 UTCTORNADO6 Nw DimmittCastro, TXREPORTED BY A MOTORIST TO S.O.
19:49 UTCTORNADO8 N DimmittCastro, TX
21:46 UTCHAIL 12 Ene HerefordDeaf Smith, TXQUARTER SIZE AND JUST A LITTLE BIGGER THAN QUARTER SIZE.
22:30 UTCFLOOD3 N DawnDeaf Smith, TXWATER ABOUT 2 INCHES DEEP FLOWING ACROSS FM 809 JUST SOUTH OF FM 1062.

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

This ground now

The live radar over the trackEvery 2018 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

The other tornadoes of October 7, 2018

4 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
October 74:22 PM CDTEF0Kiowa, OK0.110
October 75:10 PM CDTEF0Kiowa, OK0.110
October 75:38 PM CDTEF0Murray, OK1.020
October 77:46 PM CDTEF0Osage, OK1.5225$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.