Tornadoes · United States · Texas · 2006

F0 tornado, Anna, Texas, May 9, 2006

This F0 tornado ran 0.1 miles across Collin County on May 9, 2006, touching down at 10:26 PM CDT and reaching 25 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
May 9, 2006
Touchdown
10:26 PM CDT (03:26 UTC)
Path length
0.1 miles (0.2 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
County
Collin County
Touchdown point
33.370, -96.580
Lift-off point
33.370, -96.580
Record number
507

What the Weather Service recorded

Spotters reported a brief tornado just northwest of Anna. No significant damage was noted during a storm survey conducted by the National Weather Service in Fort Worth.

A damage survey conducted by the National Weather Service in Fort Worth found that storage building roofs were damaged and tree limbs were down along FM 2862, one to two miles northeast of Anna. This was the extent of the damage associated with this particular tornado.

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

The warnings

18 minutes of warning. NWS FWD issued a tornado warning for this county at 03:08 UTC, 18 minutes before the tornado touched down, in force until 04:00 UTC.

Issued (UTC)ExpiredProductOffice
01:59 UTC03:00 UTCSevere Thunderstorm WarningFWD
02:59 UTC04:00 UTCSevere Thunderstorm WarningFWD
03:08 UTC04:00 UTCTornado WarningFWD
03:46 UTC08:07 UTCSevere Thunderstorm WatchFWD
15:26 UTC00:00 UTCWind AdvisoryFWD

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 01:07 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.

Fort Worth, TX (KFWD), 00:00Z

3.4 hours before the tornado, 89 km from the path. May 10, 2006.

Skew-T log-pSkew-T log-p diagram, Fort Worth, TX at 00:00Z on 2006-05-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 4874 joules per kilogram, CIN -8, lifted condensation level 1628 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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, Fort Worth, TX at 00:00Z on 2006-05-10The 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 39 square meters per square second, 0 to 6 km bulk shear 42 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
4874 J/kg
Mixed-layer CIN
-8 J/kg
Surface CAPE
5978 J/kg
Mixed-layer LCL
1628 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
7 kt
0-1 km storm-relative helicity
39 m²/s²
0-3 km storm-relative helicity
154 m²/s²
Significant tornado parameter
0.9
Supercell composite
13.1
0-3 km lapse rate
8.3 K/km

Open this sounding in Storm Lab

Fort Worth, TX (KFWD), 12:00Z

8.6 hours after it, 89 km from the path. May 10, 2006.

Skew-T log-pSkew-T log-p diagram, Fort Worth, TX at 12:00Z on 2006-05-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2365 joules per kilogram, CIN -242, lifted condensation level 996 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, Fort Worth, TX at 12:00Z on 2006-05-10The 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 263 square meters per square second, 0 to 6 km bulk shear 53 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
2365 J/kg
Mixed-layer CIN
-242 J/kg
Surface CAPE
1264 J/kg
Mixed-layer LCL
996 m above ground
0-6 km bulk shear
53 kt
0-1 km bulk shear
41 kt
0-1 km storm-relative helicity
263 m²/s²
0-3 km storm-relative helicity
284 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.3
0-3 km lapse rate
4.1 K/km

Open this sounding in Storm Lab

The surface observations

Mc Kinney (TKI), 21 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
01:53 UTC8474180° 13 kt221001.7
02:00 UTC84.273.4180° 9 kt1002
02:53 UTC8374170° 8 kt1002.7
03:01 UTC84.273.4180° 11 kt161002.4TS
03:53 UTC8374200° 14 kt1003.4TS
04:05 UTC82.473.4190° 10 kt1003.7
04:53 UTC8274180° 8 kt1003.4

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

The radar

The Dallas/Ft Worth radar (KFWS), 111 km away, was scanning. The volume nearest the touchdown began at 03:26 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
01:55 UTCTSTM WND GST 607 S ShermanGrayson, TXPUBLIC REPORT RELAYED BY MEDIA.
01:55 UTCHAIL 0.752 N GunterGrayson, TX
02:07 UTCHAIL 0.75Van AlstyneGrayson, TXREPORTED ALONG INTERSTATE 75.
02:07 UTCHAIL 0.75Van AlstyneGrayson, TXREPORTED ALONG U.S. 75.
02:23 UTCHAIL 0.755 N Van AlstyneGrayson, TXRELAYED BY AMATEUR RADIO OPERATORS.
02:41 UTCHAIL 1GunterGrayson, TX
03:04 UTCHAIL 1.75MckinneyCollin, TXGOLF BALL SIZE HAIL REPORTED AT FM 121 AND U.S. 75.
03:04 UTCHAIL 1.75MckinneyCollin, TXGOLF BALL SIZE HAIL REPORTED AT HIGHWAY 121 AND U.S. 75.
03:29 UTCTORNADO1 N AnnaCollin, TXTORNADO REPORTED BY NUMEROUS SPOTTERS JUST NORTH OF ANNA...POWER FLASHES REPORTED.
03:30 UTCTORNADOWestminsterCollin, TX*** 3 FATAL, 3 INJ *** AN ELDERLY COUPLE AND A TEENAGER WERE KILLED IN THE TOWN OF WESTMINSTER WITH EXTENSIVE DAMAGE IN AND AROUND TOWN. TIME ESTIMATED. DAMAGE SURVEY
03:30 UTCTORNADOWestminsterCollin, TX*** 3 FATAL, 3 INJ *** AN ELDERLY COUPLE AND A TEENAGER WERE KILLED IN THE TOWN OF WESTMINSTER WITH EXTENSIVE DAMAGE IN AND AROUND TOWN. TIME ESTIMATED. DAMAGE SURVEY WILL BE CONDUCTED WEDNESDAY MORNING.
03:37 UTCTORNADO7 Ne AnnaGrayson, TXPREVIOUS TORNADO DISSIPATED AND A SECOND LARGER ONE FORMED...DEBRIS REPORTED.
04:05 UTCHAIL 1TrentonFannin, TXTRENTON POLICE OFFICER REPORTED QUARTER SIZED HAIL IN TRENTON...HE ALSO HEARD REPORTS OF GOLF BALL HAIL NEAR TOWN
04:24 UTCTSTM WND DMGDodd CityFannin, TXLARGE TREE DOWN ON A HOUSE AND POWER LINES BLOWN DOWN IN DODD CITY.

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

This ground now

The live radar over the trackEvery 2006 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

The other tornadoes of May 9, 2006

9 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 95:00 PM CDTF0Limestone, AL5.060
May 95:05 PM CDTF0Limestone, AL0.130$20,000
May 96:59 PM CDTF0Coal, OK0.220
May 98:01 PM CDTF0Atoka, OK0.630
May 98:04 PM CDTF0Atoka, OK0.220
May 99:10 PM CDTF0Grayson, TX0.125
May 99:30 PM CDTF2Childress, TX1.51751$5.7 million
May 910:33 PM CDTF0Collin, TX0.440$30,000
May 910:37 PM CDTF3Collin, TX9.3300310$1.5 million

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.