EF1 tornado, Seymour to Seymour Owen Fld Arp, Missouri, December 1, 2018

1. EF065 to 85 mph

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

2. EF186 to 110 mphthis tornado

   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

EF1

Date

December 1, 2018

Touchdown

1:22 AM CST (07:22 UTC)

Lifted

1:29 AM CST (07:29 UTC)

On the ground

7 minutes

Path length

4.2 miles (6.7 km)

Path width

75 yards (69 m)

Deaths

0

Injuries

0

Property damage

$90,000

County

Webster County

Touchdown point

37.170, -92.760

Lift-off point

37.206, -92.699

Record number

1812010122-01

5 damage points were recorded along this path by NWS SGF, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 90 mph.

• Large branches broken off of hardwood trees.
• Roof heaviliy damaging on out building.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

Severe thunderstorms and tornadoes developed within a Quasi-Linear Convective System that moved across the region during the late evening of November 30th and continued into the early morning of the 1st. The parent storm system intensified over the southern Plains and tracked northeast into northern Missouri. Widespread severe wind gusts between 60 and 80 mph, hail and isolated tornadoes occurred. Seven tornadoes were confirmed over southwest and south central Missouri. The tornadoes were rated EF-0 to EF-1 based on NWS Storm Surveys. Unfortunately, there was one fatality that occurred in Aurora, Missouri when a tornado struck a local motel.

An EF-1 tornado formed 2 miles north northeast of Seymour and tracked northeast and dissipated approximately 6 miles northeast of Seymour. There was significant damage to barns along with uprooted trees along the tornadoes path.

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

18 minutes of warning. NWS SGF issued a tornado warning for this county at 07:04 UTC, 18 minutes before the tornado touched down, in force until 07:30 UTC.

The county was under a tornado watch, issued at 03:52 UTC and running to 07:49 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 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.

Lebanon (LBO), 52 km from the path, in the two hours either side.

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

The Springfield radar (KSGF), 60 km away, was scanning. The volume nearest the touchdown began at 07:24 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 2018 tornado in MissouriEvery tornado in Missouri since 1950Warnings in force in Missouri nowThe forecast where you are

39 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.