Tornadoes · United States · Oklahoma · 2020

Unrated tornado, Davidson, Oklahoma, May 15, 2020

This Unrated tornado ran 0.3 miles across Tillman County on May 15, 2020, touching down at 7:32 PM CDT and reaching 50 yards wide. It killed nobody.

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 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. Unratedthis tornado

    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
Unrated
Date
May 15, 2020
Touchdown
7:32 PM CDT (00:32 UTC)
Path length
0.3 miles (0.5 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Tillman County
Touchdown point
34.229, -99.006
Lift-off point
34.229, -99.006
Record number
2005151832-01

What the Weather Service recorded

An outflow boundary and a dryline both led to numerous thunderstorms developing during the afternoon and evening of the 15th, with hail, wind, and a brief tornado reported.

A storm chaser photographed a tornado east of Davidson. The specific location is estimated based on the spotter's location and viewing angle and radar. No damage was reported.

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.

The county was under a severe thunderstorm watch, issued at 18:42 UTC and running to 02:33 UTC.

Issued (UTC)ExpiredProductOffice
18:42 UTC02:33 UTCSevere Thunderstorm WatchOUN
20:00 UTC07:30 UTCFlood WatchOUN
22:32 UTC00:30 UTCFlood AdvisoryOUN
22:57 UTC00:00 UTCSevere Thunderstorm WarningOUN
23:04 UTC02:00 UTCFlash Flood WarningOUN
23:12 UTC00:15 UTCSevere Thunderstorm WarningOUN
23:35 UTC00:15 UTCSevere Thunderstorm WarningOUN
23:58 UTC01:15 UTCSevere Thunderstorm WarningOUN
23:59 UTC03:00 UTCFlash Flood WarningOUN
00:33 UTC03:30 UTCFlash Flood WarningOUN
00:58 UTC02:00 UTCSevere Thunderstorm WarningOUN
01:25 UTC01:55 UTCSevere Thunderstorm WarningOUN
03:27 UTC07:33 UTCFlood 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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:47 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), 12:00Z

11.5 hours after it, 184 km from the path. May 16, 2020.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 12:00Z on 2020-05-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -92604, lifted condensation level 1097 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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 2020-05-16The 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 -45 square meters per square second, 0 to 6 km bulk shear 17 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
0 J/kg
Mixed-layer CIN
-92604 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1097 m above ground
0-6 km bulk shear
17 kt
0-1 km bulk shear
16 kt
0-1 km storm-relative helicity
-45 m²/s²
0-3 km storm-relative helicity
-47 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.8 K/km

Open this sounding in Storm Lab

The surface observations

Frederick (FDR), 14 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:35 UTC 391004.1
22:40 UTC80° 421004.4
22:45 UTC80° 361004.4
22:50 UTC80° 1004.4
22:53 UTC736480° 28 kt421004.4
22:55 UTC80° 1004.4
23:00 UTC80° 32 kt1004.4
23:05 UTC80° 31 kt371003.7
23:06 UTC726380° 32 kt411003.7VCTS
23:10 UTC90° 29 kt341004.1
23:15 UTC80° 32 kt391004.4
23:20 UTC80° 30 kt371005.4
23:25 UTC716590° 27 kt381005.8-TSRA
23:30 UTC90° 32 kt1005.1-RA BR
23:34 UTC696690° 34 kt411004.7+TSRA BR
23:35 UTC 35 kt411005.1+RA BR
23:40 UTC80° 35 kt431004.7+RA BR
23:44 UTC676590° 37 kt511005.1+TSRA FG
23:45 UTC90° 38 kt441005.4+RA FG
23:50 UTC50° 23 kt291005.8+RA FG
23:53 UTC676550° 25 kt441006.4+TSRA BR
23:55 UTC50° 22 kt1006.8+RA BR
00:00 UTC676650° 20 kt331007.1TSRA BR
00:05 UTC60° 26 kt1007.5+RA BR
00:10 UTC50° 24 kt1007.8+RA BR
00:15 UTC666550° 18 kt331008.1+TSRA BR
00:20 UTC 29 kt381007.5+RA BR
00:24 UTC666330° 30 kt391008.1+TSRA BR
00:25 UTC 30 kt371008.1+RA BR
00:30 UTC 431009.5+RA BR
00:35 UTC 28 kt341009.1+RA BR
00:40 UTC 29 kt+RA
00:44 UTC6261360° 21 kt351009.8+TSRA
00:45 UTC 22 kt291010.2+RA
00:50 UTC 18 kt1011.5+RA BR
00:53 UTC6059350° 18 kt291011.5+TSRA BR
00:55 UTC 19 kt1011.9+RA BR
01:00 UTC 19 kt241012.5+RA BR
01:05 UTC 20 kt1012.9+RA FG
01:08 UTC6261250° 14 kt271013.2+TSRA FG
01:10 UTC210° 14 kt221013.2+RA FG
01:11 UTC6261220° 16 kt271013.2+TSRA BR
01:15 UTC 18 kt1013.2+RA BR
01:17 UTC6261190° 14 kt231012.9+TSRA BR
01:20 UTC190° 11 kt1012.5+RA BR
01:25 UTC6262180° 12 kt1012.2+TSRA BR
01:30 UTC 14 kt1012.2+RA BR
01:35 UTC 13 kt1011.9+RA BR
01:40 UTC150° 11 kt1011.5+RA BR
01:45 UTC130° 15 kt1011.9+RA BR
01:50 UTC130° 16 kt1012.2RA BR
01:53 UTC6260130° 15 kt1012.2TSRA
01:55 UTC130° 14 kt1012.2RA
02:00 UTC130° 10 kt1012.2RA
02:05 UTC140° 11 kt1012.2-RA
02:10 UTC120° 13 kt1012.2-RA
02:15 UTC 17 kt1012.2-RA
02:20 UTC 17 kt1012.2-RA
02:25 UTC 18 kt1011.9RA
02:26 UTC605990° 17 kt1011.9VCTS RA
02:30 UTC100° 16 kt1011.9RA

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

The radar

The Altus AFB radar (KFDR), 15 km away, was scanning. The volume nearest the touchdown began at 00:32 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
22:21 UTCHAIL 11 S AltusJackson, OKON HIGHWAY 283.
22:23 UTCHAIL 1.753 S AltusJackson, OKON HIGHWAY 283.
22:24 UTCHAIL 12 S AltusJackson, OK
22:36 UTCHAIL 1.25AltusJackson, OK
22:37 UTCHAIL 22 Se AltusJackson, OKMPING
23:20 UTCHAIL 14 E HeadrickTillman, OKVIA SOCIAL MEDIA.
23:37 UTCHAIL 1.25S DavidsonTillman, OK
23:40 UTCFLASH FLOODNw AltusJackson, OKHIGH WATER RESCUE.
23:41 UTCTSTM WND GST 593 Sse FrederickTillman, OK
23:41 UTCHAIL 0.75DavidsonTillman, OKVIA EMERGENCY MANAGER.
23:46 UTCHAIL 1.752 S FrederickTillman, OKON HIGHWAY 183.
23:50 UTCTSTM WND DMGFrederickTillman, OKHOUSE TIN ROOF REMOVED BY WINDS. TIME ESTIMATED BY RADAR.
23:51 UTCHAIL 1FrederickTillman, OK
00:15 UTCHAIL 15 S FrederickTillman, OKON HIGHWAY 183.
00:32 UTCTORNADO4 Ese DavidsonTillman, OKA BRIEF TORNADO WAS OBSERVED BY A STORM CHASER.
01:01 UTCFLASH FLOODFrederickTillman, OKHEAVY STREET FLOODING REPORTED WITH 3 INCHES OF RAIN.
01:37 UTCHAIL 0.88GrandfieldTillman, OK

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

This ground now

The live radar over the trackEvery 2020 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

The other tornadoes of May 15, 2020

2 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 159:38 AM CDTEF1Muskogee, OK4.85251$350,000
May 155:59 PM EDTEF1Saratoga, NY1.850

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.