Tornadoes · United States · Texas · 2004

F0 tornado, Von Ormy to Kelly Afb, Texas, November 16, 2004

From Von Ormy to Kelly Afb, this F0 tornado ran 0.1 miles across Bexar County on November 16, 2004, touching down at 6:40 PM CST and reaching 20 yards wide. It killed nobody.

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
November 16, 2004
Touchdown
6:40 PM CST (00:40 UTC)
Path length
0.1 miles (0.2 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
County
Bexar County
Touchdown point
29.370, -98.670
Lift-off point
29.370, -98.670
Record number
511

What the Weather Service recorded

Skywarn-trained Amateur Radio Operators observed a small tornado that dropped into an open area. The tornado was about 20 yards wide and continued over the ground for less than a quarter mile. It caused no damage and was rated F0 on the Fujita Scale.

A small and short-lived tornado was observed by the Kelly AFB Weather Station. It was in open country and caused no damage. It was rated F0 on the Fujita Scale

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

The warnings

37 minutes of warning. NWS EWX issued a tornado warning for this county at 00:03 UTC, 37 minutes before the tornado touched down, in force until 00:45 UTC.

Issued (UTC)ExpiredProductOffice
23:08 UTC05:15 UTCFlash Flood WarningEWX
00:03 UTC00:45 UTCTornado WarningEWX
01:13 UTC01:45 UTCTornado WarningEWX
01:45 UTC02:00 UTCTornado WarningEWX
05:10 UTC08:15 UTCFlash Flood WarningEWX
08:07 UTC14:00 UTCFlash Flood WarningEWX
13:25 UTC17:15 UTCFlash Flood WarningEWX

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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 20:00 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.

Del Rio, TX (KDRT), 00:00Z

0.7 hours before the tornado, 210 km from the path. November 17, 2004.

Skew-T log-pSkew-T log-p diagram, Del Rio, TX at 00:00Z on 2004-11-17Temperature 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 -55875, lifted condensation level 727 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, Del Rio, TX at 00:00Z on 2004-11-17The 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 -49 square meters per square second, 0 to 6 km bulk shear 56 knots.19395878Sfc1 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
-55875 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
727 m above ground
0-6 km bulk shear
56 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
-49 m²/s²
0-3 km storm-relative helicity
-12 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.1 K/km

Open this sounding in Storm Lab

Del Rio, TX (KDRT), 12:00Z

11.3 hours after it, 210 km from the path. November 17, 2004.

Skew-T log-pSkew-T log-p diagram, Del Rio, TX at 12:00Z on 2004-11-17Temperature 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 -107, lifted condensation level 593 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, Del Rio, TX at 12:00Z on 2004-11-17The 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 -16 square meters per square second, 0 to 6 km bulk shear 49 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
0 J/kg
Mixed-layer CIN
-107 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
593 m above ground
0-6 km bulk shear
49 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
-16 m²/s²
0-3 km storm-relative helicity
-6 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.9 K/km

Open this sounding in Storm Lab

The surface observations

Kelly Afb (SKF), 9 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:45 UTC78.868150° 9 kt1016.9TS
22:55 UTC7768130° 8 kt1017.3TS VCSH
23:55 UTC71.669.8300° 2 kt1017.9TS VCSH
00:54 UTC71.671.6300° 2 kt1018.6-TSRA
00:55 UTC71.671.6260° 4 kt1019-TSRA
01:05 UTC71.671.6180° 7 kt1019+TSRA
01:12 UTC6868280° 24 kt331019+TSRA
01:17 UTC6868310° 10 kt211019+FC +TSRA
01:23 UTC6868300° 10 kt211019+FC +TSRA
01:32 UTC6868280° 18 kt251019+TSRA
01:39 UTC64.464.4290° 13 kt251020+TSRA
01:52 UTC64.464.4290° 11 kt1021+TSRA BR
01:55 UTC64.464.4320° 7 kt1020.3+TSRA BR
02:03 UTC64.464.4320° 7 kt1020.3+TSRA BR
02:25 UTC64.464.4340° 7 kt1020.3+TSRA +SHRA BR

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

The radar

The Austin/San Antonio radar (KEWX), 72 km away, was scanning. The volume nearest the touchdown began at 00:37 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.

This ground now

The live radar over the trackEvery 2004 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

The other tornadoes of November 16, 2004

8 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
November 164:52 PM CSTF0Travis, TX0.5100
November 166:43 PM CSTF0Gillespie, TX2.0100
November 167:10 PM CSTF0Gillespie, TX0.120
November 167:23 PM CSTF0Bexar, TX0.120
November 167:27 PM CSTF0Bexar, TX0.120
November 168:20 PM CSTF0Blanco, TX7.0200
November 168:40 PM CSTF1Blanco, TX12.0300
November 169:00 PM CSTF1Comal, TX0.8200

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.