Tornadoes · United States · Texas · 1993

F1 tornado, Dekalb, Texas, May 9, 1993

This F1 tornado ran 3.0 miles across Bowie County on May 9, 1993, touching down at 5:45 PM CDT and reaching 100 yards wide. It killed nobody, and did $5,000 to $50,000 of property damage.

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 9, 1993
Touchdown
5:45 PM CDT (22:45 UTC)
Path length
3.0 miles (4.8 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
Property damage
$5,000 to $50,000
County
Bowie County
Touchdown point
33.500, -94.620
Lift-off point
33.530, -94.570
Record number
314

What the Weather Service recorded

One home destroyed, minor roof damage to 60 homes most due to falling trees, roof damage to an apartment complex, and some businesses received damage. There was also some damage to a nursing home. The tornado was accompanied by 90 mile an hour straight line winds.

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.

Issued (UTC)ExpiredProductOffice
22:47 UTC00:15 UTCSevere Thunderstorm WarningSHV
00:10 UTC01:45 UTCSevere Thunderstorm WarningSHV

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 06:24 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.

Longview/Gregg, TX (KGGG), 12:00Z

10.8 hours before the tornado, 130 km from the path. May 9, 1993.

Skew-T log-pSkew-T log-p diagram, Longview/Gregg, TX at 12:00Z on 1993-05-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1091 joules per kilogram, CIN -24, lifted condensation level 566 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, Longview/Gregg, TX at 12:00Z on 1993-05-09The 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 223 square meters per square second, 0 to 6 km bulk shear 25 knots.193958Sfc1 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
1091 J/kg
Mixed-layer CIN
-24 J/kg
Surface CAPE
537 J/kg
Mixed-layer LCL
566 m above ground
0-6 km bulk shear
25 kt
0-1 km bulk shear
36 kt
0-1 km storm-relative helicity
223 m²/s²
0-3 km storm-relative helicity
305 m²/s²
Significant tornado parameter
1.0
Supercell composite
5.6
0-3 km lapse rate
4.6 K/km

Open this sounding in Storm Lab

Longview/Gregg, TX (KGGG), 00:00Z

1.2 hours after it, 130 km from the path. May 10, 1993.

Skew-T log-pSkew-T log-p diagram, Longview/Gregg, TX at 00:00Z on 1993-05-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1853 joules per kilogram, CIN -7, lifted condensation level 1079 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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, Longview/Gregg, TX at 00:00Z on 1993-05-10The 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 150 square meters per square second, 0 to 6 km bulk shear 30 knots.193958Sfc1 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
1853 J/kg
Mixed-layer CIN
-7 J/kg
Surface CAPE
1253 J/kg
Mixed-layer LCL
1079 m above ground
0-6 km bulk shear
30 kt
0-1 km bulk shear
27 kt
0-1 km storm-relative helicity
150 m²/s²
0-3 km storm-relative helicity
249 m²/s²
Significant tornado parameter
1.4
Supercell composite
14.1
0-3 km lapse rate
7.6 K/km

Open this sounding in Storm Lab

The surface observations

Texarkana Regional/Webb (TXK), 56 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:00 UTC8368160° 10 kt1012.2
22:00 UTC8367160° 12 kt191011.2
23:00 UTC8161150° 9 kt1011.9
00:00 UTC7865.84280° 30 kt451013.9SHRA
00:11 UTC63.8661.88290° 12 kt1014.2

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

This ground now

The live radar over the trackEvery 1993 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

The other tornadoes of May 9, 1993

15 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 91:30 PM CDTF2Collin, TX12.0100163$500,000 to $5 million
May 92:10 PM CDTF0Kaufman, TX0.110
May 92:15 PM CDTF0Kaufman, TX0.110
May 92:20 PM CDTF1Kaufman, TX19.0100$5,000 to $50,000
May 92:45 PM CDTF0Navarro, TX0.110
May 92:51 PM CDTF0Hill, TX0.110
May 92:51 PM CDTF0Hill, TX0.110
May 92:51 PM CDTF0Hill, TX5.0100
May 93:05 PM CDTF0Ellis, TX0.110
May 93:08 PM CDTF0Johnson, TX0.110$500 to $5,000
May 93:18 PM CDTF0Navarro, TX0.110
May 93:25 PM CDTF1Ellis, TX0.110$500 to $5,000
May 96:02 PM CDTF1Anderson, TX2.0100$50,000 to $500,000
May 97:45 PM CDTF0Comal, TX0.120
May 97:45 PM CDTF0Comal, TX0.110

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.