Tornadoes · United States · Texas · 1991

F2 tornado, Starr County, Texas, May 5, 1991

This F2 tornado ran 1.0 miles across Starr County on May 5, 1991, touching down at 8:00 AM CDT and reaching 200 yards wide. It killed nobody, and did $50,000 to $500,000 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 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 mphthis tornado

    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
F2
Date
May 5, 1991
Touchdown
8:00 AM CDT (13:00 UTC)
Path length
1.0 miles (1.6 km)
Path width
200 yards (183 m)
Deaths
0
Injuries
0
Property damage
$50,000 to $500,000
County
Starr County
Touchdown point
26.520, -98.480
Record number
443

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
07:59 UTC09:00 UTCSevere Thunderstorm WarningBRO
09:10 UTC10:15 UTCSevere Thunderstorm WarningBRO
13:22 UTC14:30 UTCSevere Thunderstorm WarningBRO

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. The outlook in force was issued at 11:44 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.

Brownsville Intl, TX (KBRO), 12:00Z

1.0 hours before the tornado, 128 km from the path. May 5, 1991.

Skew-T log-pSkew-T log-p diagram, Brownsville Intl, TX at 12:00Z on 1991-05-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 4555 joules per kilogram, CIN -262, lifted condensation level 1098 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 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, Brownsville Intl, TX at 12:00Z on 1991-05-05The 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 88 square meters per square second, 0 to 6 km bulk shear 44 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
4555 J/kg
Mixed-layer CIN
-262 J/kg
Surface CAPE
6299 J/kg
Mixed-layer LCL
1098 m above ground
0-6 km bulk shear
44 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
88 m²/s²
0-3 km storm-relative helicity
95 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.4
0-3 km lapse rate
4.8 K/km

Open this sounding in Storm Lab

Brownsville Intl, TX (KBRO), 00:00Z

11.0 hours after it, 128 km from the path. May 6, 1991.

Skew-T log-pSkew-T log-p diagram, Brownsville Intl, TX at 00:00Z on 1991-05-06Temperature 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 0, lifted condensation level NaN 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, Brownsville Intl, TX at 00:00Z on 1991-05-06The 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 64 square meters per square second, 0 to 6 km bulk shear 14 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
0 J/kg
Mixed-layer CIN
0 J/kg
Surface CAPE
2325 J/kg
Mixed-layer LCL
NaN m above ground
0-6 km bulk shear
14 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
64 m²/s²
0-3 km storm-relative helicity
238 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1
0-3 km lapse rate
5.7 K/km

Open this sounding in Storm Lab

The surface observations

Mcallen/Miller International (MFE), 45 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
11:00 UTC817870° 8 kt1009.1TS FG
12:00 UTC8077120° 8 kt1009.1FG
13:00 UTC8077100° 10 kt1010.5FG
14:00 UTC807790° 10 kt1011.2FG
14:25 UTC80° 10 kt1011.9

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

This ground now

The live radar over the trackEvery 1991 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

The other tornadoes of May 5, 1991

10 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 54:45 AM CDTF0Calcasieu Parish, LA0.217$500 to $5,000
May 59:52 AM CDTF0Hidalgo, TX0.210$50,000 to $500,000
May 510:15 AM CDTF1Yalobusha, MS2.0100$5,000 to $50,000
May 510:15 AM CDTF1Chickasaw, MS11.0880$50,000 to $500,000
May 53:00 PM CDTF0San Patricio, TX0.210
May 54:10 PM EDTF1Muscogee, GA0.3100$50,000 to $500,000
May 53:30 PM MDTF0Chaffee, CO0.210$5,000 to $50,000
May 55:18 PM CDTF1Kane, IL0.550$5,000 to $50,000
May 56:00 PM CDTF0Cook, IL0.550
May 510:30 PM EDTF0Clarendon, SC0.370

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.