Tornadoes · United States · Louisiana · 2021

EF0 tornado, Kenner to (Msy)Moisant Fld New, Louisiana, May 18, 2021

From Kenner to (Msy)Moisant Fld New, this EF0 tornado ran 0.3 miles across Jefferson Parish on May 18, 2021, touching down at 3:16 AM CDT and reaching 50 yards wide. It killed nobody, and did $100,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  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.

The record

Rating
EF0
Date
May 18, 2021
Touchdown
3:16 AM CDT (08:16 UTC)
Lifted
3:17 AM CDT (08:17 UTC)
On the ground
1 minutes
Path length
0.3 miles (0.5 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$100,000
County
Jefferson Parish
Touchdown point
29.975, -90.260
Lift-off point
29.979, -90.257
Record number
2105180216-01

The damage survey

6 damage points were recorded along this path by NWS LIX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 75 mph.

  • Insulation debris strewn about
  • Roof torn off building, roof material was badly rusted and corroded.

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

What the Weather Service recorded

In the overnight hours on May 17th into the early morning on May 18th, a cluster of slow moving severe thunderstorms associated with a weak mid-level disturbance drifted east across southeastern Louisiana. Ample overnight instability and weak steering flow resulted in damaging wind gusts, flash flooding and a few isolated weak tornadoes.

A tornado touched down just north of the river and south of the airport in Kenner and took the roof off a large building. It was noted the roof material was severely corroded and rusted. The tornado moved north and convergence in downed trees was seen just to the east of a cemetery. The tornado continued to track north- northeast, with trees down near the railroad tracks and power lines down just north of the tracks, where it looks like the tornado lifted.

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

The warnings

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.

Issued (UTC)ExpiredProductOffice
19:56 UTC17:00 UTCFlash Flood WatchLIX
08:17 UTC08:30 UTCSevere Thunderstorm WarningLIX
08:20 UTC08:36 UTCTornado WarningLIX
08:57 UTC12:00 UTCHigh Wind WarningLIX
09:50 UTC12:30 UTCFlash Flood WarningLIX
10:26 UTC10:58 UTCSevere Thunderstorm WarningLIX

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 General Thunderstorms Risk. The outlook in force was issued at 05:16 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.

Slidell Radar S, LA (KSIL), 00:00Z

8.3 hours before the tornado, 62 km from the path. May 18, 2021.

Skew-T log-pSkew-T log-p diagram, Slidell Radar S, LA at 00:00Z on 2021-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 386 joules per kilogram, CIN -6, lifted condensation level 682 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 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, Slidell Radar S, LA at 00:00Z on 2021-05-18The 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 93 square meters per square second, 0 to 6 km bulk shear 24 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
386 J/kg
Mixed-layer CIN
-6 J/kg
Surface CAPE
1930 J/kg
Mixed-layer LCL
682 m above ground
0-6 km bulk shear
24 kt
0-1 km bulk shear
21 kt
0-1 km storm-relative helicity
93 m²/s²
0-3 km storm-relative helicity
155 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.7 K/km

Open this sounding in Storm Lab

The surface observations

New Orleans - Louis Armstrong (MSY), 2 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
06:20 UTC130° 8 kt1015.9-RA
06:25 UTC120° 11 kt1015.6-RA
06:30 UTC120° 11 kt1015.2-RA
06:35 UTC120° 13 kt1015.2-RA
06:40 UTC120° 14 kt1015.2-RA
06:45 UTC130° 11 kt1014.9-RA
06:50 UTC120° 14 kt1014.9-RA
06:53 UTC7771120° 12 kt1014.9-TSRA
06:55 UTC120° 13 kt1014.9-RA
07:00 UTC120° 14 kt1014.9-RA
07:05 UTC120° 11 kt1014.9-RA
07:10 UTC130° 11 kt1014.9-RA
07:15 UTC120° 14 kt1014.6-RA
07:20 UTC120° 11 kt1014.9-RA
07:25 UTC120° 11 kt1014.9-RA
07:30 UTC120° 11 kt1014.9-RA
07:35 UTC130° 10 kt1015.2-RA
07:40 UTC230° 8 kt1015.2-RA
07:45 UTC 8 kt1015.6RA
07:50 UTC330° 5 kt1015.2RA BR
07:53 UTC7268340° 9 kt1015.2TSRA BR
07:55 UTC10° 8 kt1015.2RA BR
08:00 UTC350° 7 kt1014.9-RA
08:05 UTC 9 kt1014.6-RA
08:10 UTC 9 kt1014.6-RA
08:15 UTC 9 kt1014.6RA
08:20 UTC RA BR
08:25 UTC +RA BR
08:28 UTC7067340° 12 kt1015.2TS BR
08:30 UTC 11 kt211015.2+RA BR
08:35 UTC 11 kt211015.2+RA BR
08:40 UTC20° 5 kt1015.2RA BR
08:45 UTC 1015.2RA BR
08:50 UTC 14 kt211015.2RA BR
08:53 UTC7067110° 14 kt1015.2-TSRA BR
08:55 UTC 14 kt211015.2-RA
09:00 UTC 14 kt211015.2-RA
09:05 UTC120° 5 kt211015.2-RA
09:10 UTC120° 5 kt211015.2+RA BR
09:15 UTC120° 5 kt211015.2+RA BR
09:20 UTC120° 5 kt211015.2+RA BR
09:25 UTC120° 7 kt211015.2RA
09:30 UTC120° 7 kt211015.2RA
09:35 UTC120° 7 kt211015.2RA
09:40 UTC120° 7 kt211015.2-RA
09:45 UTC120° 7 kt211015.2-RA
09:50 UTC120° 8 kt211014.9-RA
09:53 UTC6966120° 8 kt1014.9-TSRA
09:55 UTC120° 8 kt211014.9-RA
10:00 UTC120° 8 kt211014.9-RA
10:05 UTC120° 8 kt211014.9-RA
10:10 UTC120° 8 kt211014.9-RA
10:15 UTC120° 8 kt211014.9-RA

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

What was reported nearby

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

Time (UTC)ReportWhereCountyRemark
07:50 UTCTORNADO2 Wsw MadisonvilleSt. Tammany, LAA TORNADO MOVED ONSHORE NEAR GUSTE ISLAND IN MADISONVILLE AND TRACKED N-NW ACROSS MAINLY UNINHABITED SWAMP LAND. SPORADIC SOFTWOOD AND HARDWOOD TREE DAMAGE WAS NOTED ON THE EASTERN SHORE OF AN INLET. EF-0 WITH ESTIMATED
08:16 UTCTORNADO1 W KennerJefferson, LAAN EF0 TORNADO, WITH A PATH WIDTH OF 50 YARDS, A PATH LENGTH OF 0.3 MILES AND MAXIMUM WINDS OF 75 MPH, TOUCHED DOWN JUST NORTH OF THE RIVER AND SOUTH OF THE AIRPORT IN KENNER AND TOOK THE ROOF OFF A LARGE BUILDING. IT WA
08:30 UTCFLASH FLOOD1 Ese HahnvilleSt. Charles, LANUMEROUS ROADS IMPASSABLE IN THE HAHNVILLE AREA.
08:30 UTCFLASH FLOODNorcoSt. Charles, LANUMEROUS ROADS IMPASSABLE IN THE NORCO AREA.
09:37 UTCFLASH FLOODDestrehanSt. Charles, LANUMEROUS ROADS IMPASSABLE IN THE DESTRAHAN AREA.
10:43 UTCTSTM WND DMGVioletSt. Bernard, LAWIND DAMAGE IN VIOLET ON SOUTH LAKE BOULEVARD. DAMAGE CONSISTS OF SOME METAL AWNINGS AND A PATIO COVER ALONG WITH A WOODEN GAZEBO LIFTED AND MOVED. SEVERAL LARGE OAK TREE BRANCHES ALSO DOWN.
10:50 UTCFLASH FLOOD4 Ssw New OrleansOrleans, LASEVERAL STREETS IMPASSABLE ACROSS NEW ORLEANS, MOSTLY IN THE UPTOWN AREA.

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

This ground now

The live radar over the trackEvery 2021 tornado in LouisianaEvery tornado in Louisiana since 1950Warnings in force in Louisiana nowThe forecast where you are

The other tornadoes of May 18, 2021

9 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 182:51 AM CDTEF1Saint Tammany Parish, LA1.6175
May 182:16 PM CDTEF1Clarke, MS1.4150$50,000
May 182:59 PM CDTEF0Jefferson Davis, MS1.0300$75,000
May 183:53 PM CDTEF0Simpson, MS1.5300$15,000
May 184:54 PM CDTEF1Lavaca, TX1.6150$20,000
May 186:03 PM CDTEF0Dawson, TX0.150
May 186:42 PM CDTEF1Fayette, TX3.3400$100,000
May 187:23 PM CDTEF0Conway, AR0.125$25,000
May 189:16 PM CDTEF0Scurry, TX0.050

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.