EF0 tornado, Natoma, Kansas, May 19, 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 19, 2011

Touchdown

8:30 PM CDT (01:30 UTC)

Lifted

8:31 PM CDT (01:31 UTC)

On the ground

1 minutes

Path length

0.1 miles (0.2 km)

Path width

25 yards (23 m)

Deaths

0

Injuries

0

Property damage

$25,000

County

Osborne County

Touchdown point

39.179, -99.027

Lift-off point

39.181, -99.025

Record number

1105191930-01

Following a short stretch of dry days centered around mid-month, an abrupt transition to a very wet and stormy 24-hour period commenced in North Central Kansas during the early morning hours of Thursday the 19th, followed by a separate, more significant event focused from the evening of the 19th into the early morning hours of the 20th. Although heavy rainfall and flooding was the main story, a brief EF0 tornado touched down on the edge of the Natoma city limits in Osborne County during the evening, with minor damage reported.||The initial wave of strong storms early on the 19th blossomed shortly after midnight CDT, lifting north across the six-county area before moving out or weakening by 5 AM CDT. These storms formed within a classic nocturnal low level jet axis, in an environment featuring up to around 1500 J/kg most-unstable CAPE. Locally brief, but heavy downpours were the main result of these storms, along with a lone report of penny size hail in Osborne. ||Following a break in the action that lasted most of the day, the mid-afternoon through overnight hours featured more significant rounds of strong to severe storms, which formed along and just north of a well-defined east-west oriented surface warm front. By mid afternoon, the mesoscale environment along the warm front had become quite supportive of severe weather, featuring around 1500 J/kg mixed-layer CAPE, 50-60 knots of deep-layer vertical wind shear, and 0-1 kilometer low-level shear of 20-30 knots. The first round of afternoon and evening storms affected locations mainly along and east of Highway 281 during the 4 PM to 730 PM CDT time frame. Despite the favorable proximity of the warm front, no tornadoes occurred with this initial round of afternoon storms despite the presence of an organized supercell in southern Osborne County. ||The second round of strong to severe storms affected the area primarily between 8 PM and 1 AM CDT, before finally starting to exit east out of Jewell and Mitchell Counties. Other than the brief tornado at Natoma, additional heavy rainfall was the primary impact during this time. By daylight on the 20th, 24-hour rainfall totals of 2-4 inches were common across Smith, Osborne, Jewell and Mitchell Counties. A few of the highest measured rainfall amounts included 4.17 inches in southern Mitchell County, and 3.33 inches in Smith Center. Extensive lowland and small creek flooding resulted from this soaking, along with river flooding on the North Fork Solomon at Portis, and White Rock Creek near Burr Oak. The gauge at Portis crested 5.37 feet above flood stage on the evening of the 20th.

The path of this weak tornado affected two farmsteads. Damage reported included a few broken trees, mangled cattle panels, feed bunks overturned, a hay shed moved 100 yards from its original location, and hay bales moved. A garage had some tin ripped from the roof and a light pole was broken in the yard.

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.

The county was under a tornado watch, issued at 18:44 UTC and running to 01:47 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 00:55 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.

Russell (RSL), 39 km from the path, in the two hours either side.

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

The Grand Island radar (KUEX), 136 km away, was scanning. The volume nearest the touchdown began at 01:31 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

10 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.