EF0 tornado, Seymour, Texas, April 13, 2007

1. EF065 to 85 mphthis tornado

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

2. EF186 to 110 mph

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

3. EF2111 to 135 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. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 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.

Rating

EF0

Date

April 13, 2007

Touchdown

2:38 PM CDT (19:38 UTC)

Lifted

2:48 PM CDT (19:48 UTC)

On the ground

10 minutes

Path length

6.0 miles (9.7 km)

Path width

880 yards (805 m)

Deaths

0

Injuries

0

Property damage

$500

County

Baylor County

Touchdown point

33.520, -99.310

Lift-off point

33.549, -99.209

Record number

0704131338-01

A strong upper level storm system was moving through the southwest US toward the Southern Plains during the morning of the 13th. A warm front developed and moved north in Western North Texas by afternoon, with moist and unstable air to its south. Also a dry line moved into Western north Texas south of the warm front. Thunderstorms developed over western Texas and moved in the southern parts of western north Texas. Supercell thunderstorms quickly developed and moved east through Knox, Baylor, and Archer counties. Very large hail, strong wind gusts, and tornadoes were reported with these storms. North of the warm front, severe thunderstorms moved east and affected the rest of western north Texas. Large hail was the main threat with these storms.

Storm chasers observed a large and potentially damaging tornado to the south and southeast of Seymour. Fortunately, the tornado occurred in rural areas and no structural damage was reported. The tornado formed near U.S. Highways 183/283 approximately 6 miles south-southwest of Seymour, and the width of the tornado quickly increased to about one-half mile as it moved to the east-northeast. The tornado became obscured by rain, but it believed to have dissipated before reaching state highway 114.

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

26 minutes of warning. NWS OUN issued a tornado warning for this county at 19:12 UTC, 26 minutes before the tornado touched down, in force until 19:45 UTC.

The county was under a tornado watch, issued at 17:27 UTC and running to 22:41 UTC.

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 Storm Prediction Center had this point in a Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 16:22 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 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.

Vernon (F05), 77 km from the path, in the two hours either side.

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

The Altus AFB radar (KFDR), 96 km away, was scanning. The volume nearest the touchdown began at 19:38 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.

Local storm reports within 60 km of the path, in the three hours either side.

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

The live radar over the trackEvery 2007 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

6 more were confirmed in the United States that day.

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.