EF1 tornado, Mc Nair to Baytown Humphrey Arp, Texas, September 18, 2019

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

September 18, 2019

Touchdown

4:56 PM CDT (21:56 UTC)

Lifted

5:05 PM CDT (22:05 UTC)

On the ground

9 minutes

Path length

3.0 miles (4.9 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

Property damage

$300,000

County

Harris County

Touchdown point

29.841, -95.001

Lift-off point

29.836, -94.951

Record number

1909181556-01

6 damage points were recorded along this path by NWS HGX, 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 limbs stripped off. One trunk snapped but appeard to be not a healthy tree.
• cut through tree line along Garth Road. Also had witness see tornado moving across field to west.
• Signficant barn and tree damage to feed store, farm property.
• Significant tree damage in tree line on backside of feed store.

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

A weak surface low pressure system strengthened into Tropical Storm Imelda just after noon on September 17th around 15 miles south southwest of Freeport. Imelda moved onshore near Freeport and quickly weakened to a tropical depression. Imelda moved very slowly to the north-northwest then north-northeast over the next few days and produced a few heavy rain bands that caused devastating flooding across portions of Southeast Texas...with maximum amounts over 40 inches falling mainly over a 24 hour period. Imelda is the 7th wettest tropical cyclone to impact the United States, the 5th wettest in the contiguous United States, and the 4th wettest in the state of Texas. Although fresh water flooding was the main impact, an EF-1 tornado also occured in a cell within one of the leading bands from the storm. This damaged an area on the north side of Baytown near the Highlands.

EF-1 damage was surveyed from a late afternoon tornado that touched down near the intersection of Haney Road and Barbers Hill Road. The tornado tracked to the east-southeast across a field and then crossed Garth Road, North Main Street and Hadden Road. The most significant damage on North Main Street was the loss of a metal roof on a home along with large tree limbs and the trunk of a tree snapped. A barn at a feed store was severely damaged. Trees were uprooted in a tree line behind the feed store between North Main and Hadden. Some large limbs were also downed on Hadden near the end of the damage path.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

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 General Thunderstorms Risk. The outlook in force was issued at 20:19 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.

Houston/Ellington (EFD), 31 km from the path, in the two hours either side.

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

The Houston radar (KHGX), 42 km away, was scanning. The volume nearest the touchdown began at 21:58 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 2019 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

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.