F0 tornado, Norman, Oklahoma, May 4, 1999

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.

Rating

F0

Date

May 4, 1999

Touchdown

7:00 AM CDT (12:00 UTC)

Path length

2.0 miles (3.2 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Property damage

$1,000

County

Cleveland County

Touchdown point

35.320, -97.400

Lift-off point

35.330, -97.380

Record number

464

Severe thunderstorms affected parts of southwest and central Oklahoma from early morning through mid-afternoon of the 4th. One tornado, rated F0, was observed by 2 persons about 7 miles north-northeast of Norman in Cleveland County, near Stanley Draper Lake. The only known damage occurred to fences, which were blown down near the intersection of Midwest Blvd. and SE 149th. There were also numerous reports of straight-line wind damage associated with other severe thunderstorms. Several trees were blown down at 0600 CST on Pecan Rd. and Kyme Rd. in Ponca City in Kay County. Trees were reported down again in Ponca City at 0655 CST, and power lines were downed 3 miles east of Ponca City. The last report of damage from Kay County involved a lightning strike. Lightning struck the roof of a house on North 5th St. in Ponca City, causing a large fire. Lightning also struck a barn in Yale in Payne County, setting it on fire, which then spread to a nearby barn. Other reports of damage included a blown down fence at the Postal Service Training Center in Norman in Cleveland County, large tree limbs blown down in Agra in Lincoln County, large tree limbs and power lines downed in Pauls Valley in Garvin County, and a large tree blown down at Elks Country Club in Duncan in Stephens County.

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 Slight Risk. The outlook in force was issued at 06:12 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.

The Norman radar (KTLX), 10 km away, was scanning. The volume nearest the touchdown began at 12:00 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.

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

42 more were confirmed in the United States that day.

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.