Tornadoes · United States · Oklahoma · 1999

F0 tornado, Lequire to Keota, Oklahoma, May 4, 1999

From Lequire to Keota, this F0 tornado ran 9.0 miles across Haskell County on May 4, 1999, touching down at 12:00 PM CDT and reaching 80 yards wide. It killed nobody, and did $40,000 of property damage.

The rating scale

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

  1. F040 to 72 mphthis tornado

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

  2. F173 to 112 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 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. F3158 to 206 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4207 to 260 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5261 to 318 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
F0
Date
May 4, 1999
Touchdown
12:00 PM CDT (17:00 UTC)
Path length
9.0 miles (14.5 km)
Path width
80 yards (73 m)
Deaths
0
Injuries
0
Property damage
$40,000
County
Haskell County
Touchdown point
35.130, -95.000
Lift-off point
35.200, -94.920
Record number
1090

What the Weather Service recorded

Summary of events for May 3-4 1999:Following a week-long blocking weather pattern, a strong upper level trough finally moved out of the southwestern U.S. Interactions with a dryline in western Oklahoma and a slow-moving cold front brought the largest tornado outbreak in Oklahoma history from the afternoon of May 3 through the afternoon of May 4. Most notable was the F5 tornado that moved through southern parts of the Oklahoma City metro area. While the loss of life and the heaviest property damage was limited to central Oklahoma, eastern Oklahoma got into the act with a significant number of tornadoes.While there were dozens of individual storms on May 3 and 4, there are two storms in eastern Oklahoma that stand out as outstanding. The first outstanding storm moved northeast along the I-44 corridor on the evening of May 3, causing F3 damage to Stroud in Lincoln County. The storm went on to cause significant F1 damage in Sapulpa and southwestern portions of the city of Tulsa and millions of dollars in damage.The second outstanding storm got its start in southeast Oklahoma well south of McAlester. This storm moved northeast across Pushmataha, Latimer, Haskell, LeFlore and Sequoyah Counties, producing several damaging tornadoes along the way. The final tornado touched down in Sequoyah County and tracked 39 miles to near Fayetteville, AR, producing F3 damage in an unpopulated forest in Adair County.Following a very wet April that saturated area grounds, another slow-moving weather system made flash flooding another serious problem to deal with as most rainfall quickly ran off into creeks, streams and mainstem rivers. One flash flood in Vinita caused millions of dollars in damage following the flooding of dozens of homes.

An F1 tornado that started in Latimer County 2 miles south of Panola eventually moved across the Hasell-Latimer County line, downing numerous trees 2 miles south of Lequire in extreme southern Haskell County before this tornado lifted.

An F0 tornado touched down 2 miles southwest of McCurtain and tracked to south of Keota. Along the way, the tornado heavily damaged several barns, knocked down numerous power lines, and uprooted numerous trees. The McCurtain area was especially hard-hit with numerous downed trees that blocked several roadways.

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

The warnings

12 minutes of warning. NWS TSA issued a tornado warning for this county at 16:48 UTC, 12 minutes before the tornado touched down, in force until 17:30 UTC.

Issued (UTC)ExpiredProductOffice
16:48 UTC17:30 UTCTornado WarningTSA
17:21 UTC18:15 UTCTornado WarningTSA
18:22 UTC21:15 UTCFlash Flood WarningTSA
18:44 UTC19:30 UTCSevere Thunderstorm WarningTSA
19:29 UTC20:15 UTCSevere Thunderstorm WarningTSA

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 High Risk. The outlook in force was issued at 16:50 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.

Springfield, MO (KSGF), 12:00Z

5.0 hours before the tornado, 219 km from the path. May 4, 1999.

Skew-T log-pSkew-T log-p diagram, Springfield, MO at 12:00Z on 1999-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 145 joules per kilogram, CIN -410, lifted condensation level 1235 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, Springfield, MO at 12:00Z on 1999-05-04The 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 7 square meters per square second, 0 to 6 km bulk shear 42 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
145 J/kg
Mixed-layer CIN
-410 J/kg
Surface CAPE
270 J/kg
Mixed-layer LCL
1235 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.0 K/km

Open this sounding in Storm Lab

Springfield, MO (KSGF), 00:00Z

7.0 hours after it, 219 km from the path. May 5, 1999.

Skew-T log-pSkew-T log-p diagram, Springfield, MO at 00:00Z on 1999-05-05Temperature 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 -74808, lifted condensation level 1240 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, Springfield, MO at 00:00Z on 1999-05-05The 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 216 square meters per square second, 0 to 6 km bulk shear 61 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
0 J/kg
Mixed-layer CIN
-74808 J/kg
Surface CAPE
10 J/kg
Mixed-layer LCL
1240 m above ground
0-6 km bulk shear
61 kt
0-1 km bulk shear
36 kt
0-1 km storm-relative helicity
216 m²/s²
0-3 km storm-relative helicity
224 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.0 K/km

Open this sounding in Storm Lab

The surface observations

Fort Smith Municipal (FSM), 57 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
15:53 UTC6966150° 12 kt19998.6
16:45 UTC69.866.2170° 11 kt20998TS
16:53 UTC7066170° 10 kt18998TS
17:19 UTC69.866.2150° 11 kt996.3TS
17:53 UTC7166170° 12 kt20996.3-RA
18:15 UTC69.866.2160° 14 kt19996.3+TSRA BR
18:19 UTC69.866.2160° 11 kt19996.3TSRA BR
18:30 UTC69.866.2160° 11 kt996.6-TSRA BR
18:39 UTC71.668150° 9 kt995.9TS
18:53 UTC7268150° 10 kt995.6

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

The radar

The Western Arkansas radar (KSRX), 56 km away, was scanning. The volume nearest the touchdown began at 17:00 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.

This ground now

The live radar over the trackEvery 1999 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

The other tornadoes of May 4, 1999

42 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 41:59 AM CDTF0Muskogee, OK0.550
May 42:00 AM CDTF1Cherokee, OK3.0100$40,000
May 42:55 AM CDTF2Schleicher, TX23.0250$10,000
May 43:11 AM CDTF1Adair, OK0.550$1,000
May 47:00 AM CDTF0Cleveland, OK2.050$1,000
May 47:30 AM CDTF0Osage, OK0.550
May 410:50 AM CDTF1Pushmataha, OK1.050$1,000
May 411:30 AM CDTF1Latimer, OK14.0100$40,000
May 412:21 PM CDTF1LeFlore, OK0.50$110,000
May 412:34 PM CDTF1Sequoyah, OK2.080$90,000
May 412:45 PM CDTF2Red River, TX to OK14.61007$600,000
May 412:54 PM CDTF3Sequoyah, OK to AR38.20$100,000
May 41:49 PM CDTF3St. Clair, MO3.02001$50,000
May 42:02 PM CDTF1McPherson, KS8.00$1.1 million
May 42:04 PM CDTF3Franklin, TX to AR71.550122$125 million
May 42:08 PM CDTF0Saline, KS5.00
May 42:15 PM CDTF0Ellsworth, KS1.00
May 42:23 PM CDTF0McPherson, KS2.00
May 42:45 PM CDTF0Benton, MO0.150$10,000
May 42:45 PM CDTF0Lincoln, KS6.00
May 43:03 PM CDTF2Gregg, TX2.2117$6.0 million
May 43:06 PM CDTF2Gregg, TX9.702$19 million
May 43:40 PM CDTF0Harrison, TX2.20
May 43:50 PM CDTF1Harrison, TX4.650
May 44:35 PM CDTF1Marion, KS20.00$80,000
May 45:00 PM CDTF0Van Zandt, TX0.20
May 45:04 PM CDTF1Nevada, AR4.850$10,000
May 45:15 PM CDTF0Johnson, AR0.10
May 45:15 PM CDTF0Geary, KS0.550$1,000
May 45:20 PM CDTF0Henderson, TX0.210
May 45:28 PM CDTF2Bossier Parish, LA10.0250$300,000
May 45:30 PM CDTF1Morris, KS4.0100
May 45:54 PM CDTF0Geary, KS5.0100
May 46:13 PM CDTF0Clark, AR0.10
May 46:15 PM CDTF2Columbia, AR6.5100$150,000
May 46:30 PM CDTF0Wabaunsee, KS1.50
May 46:38 PM CDTF1Anderson, TX1.01504$300,000
May 46:43 PM CDTF3Columbia, AR9.0100$600,000
May 47:10 PM CDTF0Pottawatomie, KS0.20
May 47:14 PM CDTF0Anderson, TX0.210
May 47:37 PM CDTF0Jackson, KS0.230
May 47:52 PM CDTF2Cherokee, TX22.7200

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.