Tornadoes · United States · Texas · 2003

F0 tornado, Nacogdoches, Texas, April 6, 2003

This F0 tornado ran 0.2 miles across Nacogdoches County on April 6, 2003, touching down at 3:50 PM CDT and reaching 25 yards wide. It killed nobody, and did $30,000 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 mphthis tornado

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mph

    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
F0
Date
April 6, 2003
Touchdown
3:50 PM CDT (20:50 UTC)
Path length
0.2 miles (0.3 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
Property damage
$30,000
County
Nacogdoches County
Touchdown point
31.600, -94.670
Lift-off point
31.600, -94.670
Record number
63

What the Weather Service recorded

A strong thunderstorm moved from west to east across the southwest portion of the city of Nacogdoches. Damage was minimal with a couple of homes damaged from fallen trees and large broken limbs. This tornado may have been spawned from a microburst about 1/2 mile to the northwest. The tornado also appeared to have had a clockwise rotation perhaps as a southern bookend type of tornado.

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

The warnings

11 minutes of warning. NWS SHV issued a tornado warning for this county at 20:39 UTC, 11 minutes before the tornado touched down, in force until 21:30 UTC.

Issued (UTC)ExpiredProductOffice
20:39 UTC21:30 UTCTornado 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 High Risk, with a 0.15 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 19:26 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.

Shreveport, LA (KSHV), 12:00Z

8.8 hours before the tornado, 131 km from the path. April 6, 2003.

Skew-T log-pSkew-T log-p diagram, Shreveport, LA at 12:00Z on 2003-04-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1292 joules per kilogram, CIN -53, lifted condensation level 492 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, Shreveport, LA at 12:00Z on 2003-04-06The 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 259 square meters per square second, 0 to 6 km bulk shear 43 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
1292 J/kg
Mixed-layer CIN
-53 J/kg
Surface CAPE
324 J/kg
Mixed-layer LCL
492 m above ground
0-6 km bulk shear
43 kt
0-1 km bulk shear
29 kt
0-1 km storm-relative helicity
259 m²/s²
0-3 km storm-relative helicity
405 m²/s²
Significant tornado parameter
2.5
Supercell composite
20.3
0-3 km lapse rate
5.1 K/km

Open this sounding in Storm Lab

Shreveport, LA (KSHV), 00:00Z

3.2 hours after it, 131 km from the path. April 7, 2003.

Skew-T log-pSkew-T log-p diagram, Shreveport, LA at 00:00Z on 2003-04-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 557 joules per kilogram, CIN -154, lifted condensation level 836 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, Shreveport, LA at 00:00Z on 2003-04-07The 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 184 square meters per square second, 0 to 6 km bulk shear 60 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
557 J/kg
Mixed-layer CIN
-154 J/kg
Surface CAPE
462 J/kg
Mixed-layer LCL
836 m above ground
0-6 km bulk shear
60 kt
0-1 km bulk shear
27 kt
0-1 km storm-relative helicity
184 m²/s²
0-3 km storm-relative helicity
164 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.8
0-3 km lapse rate
5.2 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 2003 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

The other tornadoes of April 6, 2003

17 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 611:44 AM CDTF0Franklin Parish, LA0.850$30,000
April 611:50 AM CDTF0Warren, MS0.725$10,000
April 611:50 AM CDTF0Yazoo, MS0.325$20,000
April 611:57 AM CDTF0Yazoo, MS4.050$100,000
April 612:45 PM CDTF2Rusk, TX4.92206$2.3 million
April 612:58 PM CDTF0Madison, MS0.325$30,000
April 61:23 PM CDTF0Rankin, MS0.525$50,000
April 61:30 PM CDTF3Cherokee, TX38.2440$9.0 million
April 63:00 PM CDTF0Newton, MS12.5200$800,000
April 63:41 PM CDTF2Angelina, TX27.5440$2.5 million
April 62:50 PM MDTF0Canyon, ID1.07
April 64:16 PM CDTF0Jackson Parish, LA5.550$40,000
April 65:39 PM CDTF0Humphreys, MS0.525$30,000
April 67:15 PM CDTF0Madison, MS0.325$30,000
April 67:30 PM CDTF1Hinds, MS5.01002$500,000
April 67:37 PM CDTF2Lincoln, MS11.01,2306$1.1 million
April 67:42 PM CDTF1Rankin, MS4.050$300,000

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.