EF0 tornado, Stanley to Lenexa, Kansas, May 25, 2011

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.

Rating

EF0

Date

May 25, 2011

Touchdown

11:22 AM CDT (16:22 UTC)

Path length

0.1 miles (0.1 km)

Path width

40 yards (37 m)

Deaths

0

Injuries

0

County

Johnson County

Touchdown point

38.883, -94.667

Lift-off point

38.883, -94.667

Record number

1105251022-01

A very warm and moist airmass had advected northwest into the area, during the morning hours of May 25, 2011, with the development of an intensifying warm front, across extreme east central Kansas. Due to ample lift, provided by the strong upper level storm system just west of Kansas City, a little bit of clearing, made the rapid development of thunderstorms along and ahead of the cold front possible. As these storms lifted northward and rotated around the surface area of low pressure, they would rapidly begin to rotate, as they reached the enhanced winds near the warm front. ||There were four tornadoes reported, and confirmed by NWS damage survey crews and/or law enforcement. The tornadoes that occurred, were associated with the smaller cousin of the classic central plains supercell thunderstorm, called a mini- or low-topped supercell thunderstorm. Mini-supercells, typically occur in association with a cold-core upper level low pressure system, and are much smaller in height and areal expanse, than the classic supercell storm. But regardless of their size, mini-supercells still possess the mechanics to produce brief tornadoes. ||Brief tornado touchdowns were observed near Louisburg, rolling a pickup truck on Highway 69, and around the Overland Park area, with damage to a middle school and several trees, just north of 159th Street, between Nall and Roe Roads.

At 1010CST an EF0 tornado touched 1.2 miles south southeast of Stanley. The tornado moved north northeast and lifted at 1012CST, around 0.9 miles southeast of Stanley. Roof damage was observed at the Blue Valley Middle School, and several trees were damaged, north of 159th Street, between Roe and Nall.

At 1022CST a brief EF0 tornado touchdown, was observed 2.5 miles north northwest of Stanley. The tornado touched down and then went right back up. No damage was observed.

At 1038CST an EF0 tornado made a brief touchdown, 0.9 miles south of Lenexa. The tornado touched down and then went right back up. No damage was observed.

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

12 minutes of warning. NWS EAX issued a tornado warning for this county at 16:10 UTC, 12 minutes before the tornado touched down, in force until 16:45 UTC.

The county was under a tornado watch, issued at 15:40 UTC and running to 20:39 UTC.

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, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 12:55 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.

Olathe (Ojc) (OJC), 7 km from the path, in the two hours either side.

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

The Pleasant Hill radar (KEAX), 36 km away, was scanning. The volume nearest the touchdown began at 16:20 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.

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

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

The live radar over the trackEvery 2011 tornado in KansasEvery tornado in Kansas since 1950Warnings in force in Kansas nowThe forecast where you are

93 more were confirmed in the United States that day.

All 94 of them

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.