EF0 tornado, Swedehome, Nebraska, April 27, 2014

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

April 27, 2014

Touchdown

5:17 PM CDT (22:17 UTC)

Lifted

5:18 PM CDT (22:18 UTC)

On the ground

1 minutes

Path length

0.4 miles (0.6 km)

Path width

45 yards (41 m)

Deaths

0

Injuries

0

County

Polk County

Touchdown point

41.201, -97.707

Lift-off point

41.206, -97.706

Record number

1404271617-01

2 damage points were recorded along this path by NWS GID, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 75 mph.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

Isolated to scattered severe thunderstorms raked across portions of South Central Nebraska on this Sunday afternoon, resulting in not only several reports of large hail and damaging winds, but also Nebraska's first three tornadoes of 2014. Fortunately, these tornadoes were of the weak and brief variety (rated EF-0) and resulted in no reports of damage. The first tornado touched down shortly before 230 PM CDT in far northern Franklin County near Upland. The other two tornadoes occurred a few hours later between 430-530 PM, associated with the strongest, most organized supercell storm of the day as it tracked north through the far eastern counties of the local area. One of these tornadoes touched down north of Bradshaw in York County and the other in west-central Polk County several miles west-northwest of Osceola. As for hail reports, the majority of them originated from western Thayer and Fillmore and northern Adams counties, including some stones up to golf ball size. There were only a few reports of marginally severe winds, highlighted by a measured 62 MPH gust near Wood River. ||All strong to severe thunderstorms within the 24-county area occurred between 12-6 PM CDT in association with a seasonably classic and powerful, vertically-stacked low pressure system migrating northeastward into South Central Nebraska. All severe storms also concentrated east and northeast of a Lexington-Franklin line, as the far southwestern counties were spared due to the passage of a well-defined, northward-drifting surface dryline and occluding cold front. There were essentially two primary areas and modes of severe storm development. The first, which accounted for most of the day's thunderstorm activity, consisted of a broken arc of storms lifting north across mainly central and west-central portions of the area. Several individual cells within this arc drifted northwestward in sync with the counter-clockwise circulation of the parent low. The initial development got going over Dawson County between 12-1 PM CDT, but these storms yielded no reports of severe weather before departing the local area into Custer and Lincoln counties. Following a brief lull, the second and more dominant arc of convection flared up generally along an axis running from eastern Dawson to Webster counties between 130 PM and 3 PM CDT, during which time the first tornado occurred near Upland. Eventually, the eastern-most cells in the arc became the most intense as they lifted north-northwest, resulting in several hail reports along a path through counties including Adams, Hall and Sherman between 330 PM and 5 PM CDT before weakening and eventually departing the local area to the north. Meanwhile, the second primary area/mode of severe weather developed farther east, and revolved around an isolated supercell that developed over southwestern Thayer County around 230 PM CDT and then drifted almost due north for the next several hours, finally departing the local area out of far eastern Nance and Merrick counties around 6 PM CDT. This lone supercell produced both the York and Polk County tornadoes, along with several hail reports. Just to the east of this main supercell of the day, another briefly-severe storm affected far eastern York County around 5 PM CDT. All strong-severe convection vacated the entire 24-county area by around 6 PM CDT, leaving behind only lingering stratiform rain in western counties under the core of the mid level low.||On the synoptic scale, the day began with a deep, vertically stacked closed low centered over central portions of the Kansas-Colorado border area as its 984 millibar surface low started to occlude. By early afternoon, severe storm development in South Central Nebraska focused within a corridor of steep low level lapse rates under the mid-level dry slot, with the southwestern extent of storm development defined by the leading edge of the northward-drifting occluded front/dryline. By late afternoon, the deep low had migrated to near McCook, allowing the surface front to push northward through all of South Central and ending the severe threat. Ahead of this occluded front/sharp dryline, surface-based CAPE climbed to around 1000 J/kg in an environment featuring surface dewpoints in the mid-upper 50s F. Behind the boundary, dewpoints quickly crashed into the 30s F.

This tornado, which touched down northwest of the intersection of Highways 92 and 39 approximately 8 miles west-northwest of Osceola, was witnessed by multiple storm chasers. No damage was reported with this tornado.

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

23 minutes of warning. NWS GID issued a tornado warning for this county at 21:54 UTC, 23 minutes before the tornado touched down, in force until 22:30 UTC.

The county was under a tornado watch, issued at 17:16 UTC and running to 23:02 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 20:00 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 Omaha radar (KOAX), 113 km away, was scanning. The volume nearest the touchdown began at 22:16 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 2014 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

16 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.