EF0 tornado, Eldorado to Saronville, Nebraska, August 14, 2020

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

August 14, 2020

Touchdown

5:53 PM CDT (22:53 UTC)

Lifted

5:54 PM CDT (22:54 UTC)

On the ground

1 minutes

Path length

0.1 miles (0.2 km)

Path width

25 yards (23 m)

Deaths

0

Injuries

0

County

Clay County

Touchdown point

40.587, -97.921

Lift-off point

40.585, -97.921

Record number

2008141653-01

9 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.

• Crop damage in covererging pattern
• Cedar Tree damage. Crop damage. Tornado crossed road.
• Tornado started in Hay Field Photo with permission from Jason Poppe
• Crop damage/scour path. Photo with permission from Jason Poppe

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

Although it only impacted a small percentage of the 24-county South Central Nebraska area, the large and intense supercell storm that marched south-southwestward for over 90 miles through several eastern counties on this Friday afternoon/early evening was likely the local area's most noteworthy individual storm of the 2020 convective season. In addition to dropping three fairly brief EF-0 tornadoes in southeastern Hamilton and northeastern Clay counties, its main calling card was large hail, with several reports of golf ball to slightly larger than baseball size stones in Clay/Nuckolls counties, and smaller hail to around quarter size as far north as Osceola. Interestingly, damaging winds were not a major player, with no ground-truth gusts in excess of 50 MPH. Focusing on specific storm reports, and starting with the three EF-0 tornadoes, they all occurred between 5-6 p.m. CDT, touching down briefly along a roughly 15-mile long corridor from near Interstate 80 a few miles south of Hampton, down to the Saronville area. Per storm surveys, the first two tornadoes were each on the ground for roughly 2 miles. While the majority of minor damage was confined to crops and trees, a lean-to shed was destroyed and a pivot overturned. As for the hail, the largest reported was 3 diameter between Clay Center and Harvard, but towns including Sutton and Nelson endured stones to at least tennis ball size. Flooding was not much of an issue, as the storm was progressive enough to keep rainfall amounts largely under one inch. ||Breaking down the meteorological background and event timing, this was actually a fairly conditional severe weather setup for South Central Nebraska, with various pros and cons for/against robust activity. In the mid-upper levels, the local area resided a fair distance south of a vigorous shortwave trough swinging across the Dakotas towards northern MN, resulting in fairly limited forcing aloft. Also working against convection (especially widespread severe) was a plume of warm mid level temperatures, with 700 millibar values of 12-14C providing a healthy cap. On the other hand, low-level forcing was seasonably-strong, as a well-defined cold front slid southeastward into the area during the afternoon. Ahead of this boundary, a significantly-unstable airmass awaited, featuring temperatures in the upper 80s-low 90s F/dewpoints upper 60s-mid 70s F, yielding formidable mixed-layer CAPE around 4000 J/kg. This extreme instability, in the presence of sufficient deep-layer wind shear around 35 knots, clearly fostered a mesoscale environment capable of stout convection. As for what actually transpired, the main show was preceded by a broken line of non-severe, likely elevated storms that passed primarily through counties south of Interstate 80 and east of Highway 281 between 12:30-3:30 p.m. CDT. About the time this innocuous early afternoon activity was departing the local area to the southeast, a broken line of true, surface-based storms got going along the front in northeast Nebraska, with the southwestern-most cell building down into the far northeast corner of South Central Nebraska (eastern Nance/northeast Merrick/northern Polk counties) between 3-4 p.m. CDT. Within an hour thereafter, this tail end Charlie storm rapidly grew into a full-blown supercell over Polk/northern York counties, producing its first marginally-severe hail reports. During the following two hours (5-7 p.m. CDT), the storm anchored itself firmly to the surface front, with new updraft generation along its western edge promoting more of a southwestward propagation and causing it to grow larger in both intensity/size, becoming more of a supercell cluster. It was during this time that the brief tornadoes occurred along the storm's far western flank, likely driven by pronounced low-level vorticity stretching along the surface front. While the sporadic tornado touchdowns were brief, the storm continued to be a prolific hail-producer as it gradually exited the local area out of Nuckolls County into northern Kansas between 7-8 p.m. CDT, ending all South Central Nebraska convection for the night.

A brief tornado continued from Hamilton County. Cedar tree damage occurred as the tornado crossed the county road into Clay County. A pivot was overturned and crop damage occurred into a converging pattern along the tornado path.

A second brief tornado over Clay County was confirmed through video and was located about 1.5 miles southeast of Saronville. This tornado lasted no more than a minute and there was no reported damage.

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

11 minutes of warning. NWS GID issued a tornado warning for this county at 22:42 UTC, 11 minutes before the tornado touched down, in force until 23:15 UTC.

The county was under a severe thunderstorm watch, issued at 22:07 UTC and running to 01:09 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. The outlook in force was issued at 19:59 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.

Aurora (AUH), 35 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), 53 km away, was scanning. The volume nearest the touchdown began at 22:52 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 2020 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

30 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.