EF0 tornado, Greeley, Nebraska, May 27, 2012

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 27, 2012

Touchdown

5:23 PM CDT (22:23 UTC)

Lifted

5:24 PM CDT (22:24 UTC)

On the ground

1 minutes

Path length

0.1 miles (0.1 km)

Path width

15 yards (14 m)

Deaths

0

Injuries

0

County

Greeley County

Touchdown point

41.475, -98.467

Lift-off point

41.475, -98.466

Record number

1205271623-01

1 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 70 mph.

• Brief Touchdown reported by Storm Chaser. \n15 yards wide in open field\nNo damage reported.

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

Sunday of Memorial Day weekend featured a prolonged afternoon and evening outbreak of severe thunderstorms primarily within the eastern two-thirds of South Central Nebraska. In addition to dozens of reports of large hail and damaging winds over the course of seven hours between 4-11 PM CDT, there was one brief EF0 tornado reported by storm chasers in a rural area between Greeley and Wolbach around 530 PM CDT with no damage reported. Hail to at least golf ball size fell in several locations, including in or near Greeley, Geneva, Franklin, Riverton, Blue Hill and along Interstate 80 in far eastern York County. In east central Greeley County, at least one home sustained broken windows. Damaging winds estimated from 60 to at least 70 MPH overturned a number of irrigation pivots, destroyed grain bins and downed trees, with some of this wind damage reported in or near Wood River, Blue Hill and Fairfield. Rainfall-wise, several counties received 1-3 inches, with a few of the highest known measured amounts including 2.90 inches southeast of Palmer and 2.88 inches north of Osceola. Although flooding was not widespread, rainfall of around 2.60 inches in the Wood River area resulted in water over a county road.||The primary zone of severe storms was associated with a slow-moving cold front and focused roughly 20 miles either side of the Highway 281 corridor between the Kansas border and the Greeley area. However, a smaller, separate cluster of severe storms also developed east of the frontal zone, affecting counties such as Thayer, Fillmore and eastern York. In both of these areas, the initiation of severe storms occurred between 4-6 PM CDT. During these first few hours, one of the strongest, most discrete supercells of the day produced the brief tornado and large hail in Greeley County before exiting the local area into Boone County. Between 6-8 PM CDT, a mix of brief supercell and quasi-linear multicell storm structures trained along the aforementioned north-south corridor near Highway 281. Then between 8-11 PM CDT, this initially narrow zone of storms expanded eastward as northern storms weakened and southern storms became more dominant. It was during this time frame that a few intense storms passed along a corridor from Franklin to Clay Counties, including a short bowing segment that resulted in several wind damage reports. Finally by 11 PM CDT, storm intensity trended downward and no additional severe weather was reported despite activity lingering well past midnight mainly south of Interstate 80 and east of Highway 281. ||This severe weather event was anticipated several days in advance, and featured a Moderate Risk Day 1 Convective Outlook from the Storm Prediction Center. The primary forcing mechanism aloft was a strong shortwave pushing northeast out of Colorado, along the southeast periphery of a deep mid-level low centered in Montana. At the surface, the aforementioned slow-moving cold front served as the primary low-level trigger, as it aligned from northwest Kansas to northeast Nebraska at mid-afternoon. As this strong upper forcing intercepted the cold front and severe storms erupted, mesoscale convective parameters featured between 1000-2000 J/kg mixed-layer CAPE and impressive 0-6 kilometer vertical wind shear of 50-70 knots. A potentially more significant tornado threat was likely kept in check by somewhat high cloud bases, resulting from surface temperature-dewpoint spreads of 20-30F early in the event.

No damage was reported with this brief tornado touchdown.

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 severe thunderstorm watch, issued at 20:52 UTC and running to 05:00 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 Moderate Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:36 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.

Ord/Sharp Field (ODX), 44 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), 128 km away, was scanning. The volume nearest the touchdown began at 22:22 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 2012 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

4 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.