Tornadoes · United States · Oklahoma · 2018

EF1 tornado, Chickasha Arpt to Amber, Oklahoma, May 2, 2018

From Chickasha Arpt to Amber, this EF1 tornado ran 0.4 miles across Grady County on May 2, 2018, touching down at 8:05 PM CDT and reaching 25 yards wide. It killed nobody, and did $10,000 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 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.

The record

Rating
EF1
Date
May 2, 2018
Touchdown
8:05 PM CDT (01:05 UTC)
Lifted
8:06 PM CDT (01:06 UTC)
On the ground
1 minutes
Path length
0.4 miles (0.6 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
Property damage
$10,000
County
Grady County
Touchdown point
35.160, -97.866
Lift-off point
35.165, -97.863
Record number
1805021905-01

What the Weather Service recorded

Several discrete supercells formed off a dryline in the eastern parts of the panhandles in the late afternoon of the 2nd. These storms moved eastward through the evening, eventually congealing into a line before coming across central Oklahoma. QLCS tornadoes became a significant hazard at this point. After this round of storms made its way out of the area, scattered storms began to form from central Texas up into south western Oklahoma overnight, moving generally northeast into the early morning hours.

This tornado developed approximately 4 miles west-southwest of Amber, briefly moved northeast before turning east-southeast. A barn and an RV were damaged southwest of Amber, and power poles were damaged south of Amber. Tree damage was also noted just west of Interstate 44, but the tornado did not appear to cross I-44.

As one tornado was dissipating south-southeast of Amber, this tornado developed approximately 1 mile east of Amber. Trees were snapped, a roof was damaged and a carport destroyed from this brief tornado as it moved northeast.

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

The warnings

3 minutes of warning. NWS OUN issued a tornado warning for this county at 01:02 UTC, 3 minutes before the tornado touched down, in force until 01:31 UTC.

The county was under a tornado watch, issued at 18:01 UTC and running to 03:00 UTC.

Issued (UTC)ExpiredProductOffice
18:01 UTC03:00 UTCTornado WatchOUN
22:57 UTC23:45 UTCSevere Thunderstorm WarningOUN
23:36 UTC00:15 UTCSevere Thunderstorm WarningOUN
23:43 UTC00:30 UTCSevere Thunderstorm WarningOUN
00:11 UTC01:00 UTCSevere Thunderstorm WarningOUN
00:30 UTC01:30 UTCSevere Thunderstorm WarningOUN
00:43 UTC03:45 UTCFlood AdvisoryOUN
00:44 UTC01:30 UTCSevere Thunderstorm WarningOUN
01:00 UTC01:30 UTCSevere Thunderstorm WarningOUN
01:02 UTC01:31 UTCTornado WarningOUN
01:04 UTC04:00 UTCFlash Flood WarningOUN
01:06 UTC01:30 UTCTornado WarningOUN
01:17 UTC02:00 UTCSevere Thunderstorm WarningOUN
01:22 UTC04:15 UTCFlood AdvisoryOUN
01:53 UTC03:07 UTCFlash Flood WarningOUN
05:17 UTC06:00 UTCSevere Thunderstorm WarningOUN
05:59 UTC06:45 UTCSevere Thunderstorm WarningOUN
06:53 UTC07:19 UTCSevere Thunderstorm WarningOUN
06:56 UTC07:45 UTCSevere Thunderstorm WarningOUN
08:39 UTC11:45 UTCFlood AdvisoryOUN
11:20 UTC11:45 UTCSevere Thunderstorm WarningOUN
11:42 UTC12:15 UTCSevere Thunderstorm WarningOUN
12:08 UTC12:29 UTCSevere Thunderstorm WarningOUN

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 Enhanced Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:52 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.

Norman, OK (KOUN), 00:00Z

1.1 hours before the tornado, 43 km from the path. May 3, 2018.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 00:00Z on 2018-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 826 joules per kilogram, CIN -62, lifted condensation level 930 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 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, Norman, OK at 00:00Z on 2018-05-03The 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 207 square meters per square second, 0 to 6 km bulk shear 55 knots.19395878Sfc1 km3 km6 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
826 J/kg
Mixed-layer CIN
-62 J/kg
Surface CAPE
1222 J/kg
Mixed-layer LCL
930 m above ground
0-6 km bulk shear
55 kt
0-1 km bulk shear
21 kt
0-1 km storm-relative helicity
207 m²/s²
0-3 km storm-relative helicity
231 m²/s²
Significant tornado parameter
0.7
Supercell composite
5.3
0-3 km lapse rate
5.6 K/km

Open this sounding in Storm Lab

Norman, OK (KOUN), 12:00Z

10.9 hours after it, 43 km from the path. May 3, 2018.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 12:00Z on 2018-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 236 joules per kilogram, CIN -135, lifted condensation level 974 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, Norman, OK at 12:00Z on 2018-05-03The 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 85 square meters per square second, 0 to 6 km bulk shear 59 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
236 J/kg
Mixed-layer CIN
-135 J/kg
Surface CAPE
244 J/kg
Mixed-layer LCL
974 m above ground
0-6 km bulk shear
59 kt
0-1 km bulk shear
16 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
244 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
5.4 K/km

Open this sounding in Storm Lab

The surface observations

Chickasha Municipal Airport (CHK), 12 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
23:10 UTC79.269140° 15 kt181007.1VCTS
23:35 UTC78.469.3140° 12 kt1007.5TS
23:50 UTC78.469.4130° 14 kt1007.8TSHZ
00:10 UTC7869.8130° 17 kt211007.8TS
00:30 UTC77.770130° 19 kt231007.5TSHZ
00:50 UTC7165.3220° 33 kt411010.2-TSRA
01:15 UTC62.861.3160° 7 kt1011.9+TSRA BR
01:30 UTC62.862100° 20 kt241010.2+TSRA BR
01:55 UTC6462140° 19 kt251009.8TS
02:10 UTC64.262110° 16 kt221009.8
02:30 UTC6462120° 16 kt1010.2
02:50 UTC6462.4110° 14 kt1009.8

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

The radar

The Norman radar (KTLX), 57 km away, was scanning. The volume nearest the touchdown began at 01:06 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
23:41 UTCHAIL 1.25GracemontCaddo, OK
23:42 UTCTSTM WND DMG3 Wnw AnadarkoCaddo, OKMETAL ROOF TAKEN OFF HOUSE.
23:51 UTCHAIL 0.885 E BingerCaddo, OK
00:20 UTCHAIL 1.55 Ene Lake ChickashaGrady, OKMPING.
01:00 UTCTSTM WND GST 724 Wnw Rush SpringsGrady, OK
01:00 UTCTORNADO5 S PocassetGrady, OKLOFTED DEBRIS VISIBLE. PERHAPS CORRUGATED ROOFING. TORNADO STARTED AT OR JUST EAST OF HWY 81, MOVING NE. PRESENT FOR 2-3 MINS.
01:11 UTCHAIL 0.754 Ene MustangOklahoma, OK
01:35 UTCFLASH FLOOD3 Sw MincoGrady, OKLOCAL OFFICIAL REPORTED WATER FLOWING OVER ROADWAYS WEST AND SOUTHWEST OF MINCO. TIME ESTIMATED.
01:44 UTCTORNADO5 Ne NormanCleveland, OKA WEAK TORNADO IMPACTED THE NORTHEASTERN PORTIONS OF NORMAN. EF1 DAMAGE WAS SURVEYED, INCLUDING STRUCTURAL AND HARDWOOD TREE DAMAGE. PRELIMINARY PATH LENGTH IS APPROXIMATELY 8 MILES.
02:03 UTCFLASH FLOODBethanyOklahoma, OKROUTE 66 IN BETHANY CLOSED DUE TO FLOODING.
02:05 UTCFLASH FLOOD4 Ssw BethanyCanadian, OKCAR SUBMERGED IN WATER NEAR RENO AND ALIANCE BLVD/I40 AND COUNCIL.

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

This ground now

The live radar over the trackEvery 2018 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

The other tornadoes of May 2, 2018

29 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 24:05 PM CDTEF0Ottawa, KS0.020
May 24:25 PM CDTEF0Greer, OK1.730
May 24:38 PM CDTUnratedKiowa, OK1.230
May 24:51 PM CDTEF0McPherson, KS2.075
May 25:30 PM CDTEF0Marshall, KS2.330
May 25:46 PM CDTUnratedWilbarger, TX0.225
May 25:47 PM CDTEF0Marshall, KS7.760
May 26:10 PM CDTUnratedTillman, OK0.520
May 26:21 PM CDTUnratedTillman, OK0.420
May 26:26 PM CDTEF1Tillman, OK1.650$5,000
May 26:34 PM CDTEF1Tillman, OK5.5150$5,000
May 26:47 PM CDTEF2Tillman, OK4.1600$5,000
May 26:51 PM CDTEF0Butler, KS0.875
May 27:02 PM CDTUnratedTillman, OK3.550
May 27:07 PM CDTEF1Tillman, OK3.0250$4,000
May 27:18 PM CDTEF0Holt, MO4.025
May 27:45 PM CDTEF0Lyon, KS0.020
May 27:51 PM CDTEF0Coffey, KS0.025
May 27:55 PM CDTEF1Grady, OK10.0400$30,000
May 27:58 PM CDTEF1Grady, OK5.5100$20,000
May 28:04 PM CDTEF0Osage, KS0.025
May 28:42 PM CDTEF1Cleveland, OK8.0400$10,000
May 28:48 PM CDTEF1McClain, OK4.740$10,000
May 29:09 PM CDTEF1Johnson, KS4.725
May 29:19 PM CDTEF1Pottawatomie, OK0.850$2,000
May 29:22 PM CDTEF0Cass, MO0.010
May 29:24 PM CDTEF0Jackson, MO1.625
May 29:26 PM CDTEF0Jackson, MO1.325
May 210:39 PM CDTEF0Crockett, TX0.850$50,000

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.