Tornadoes · United States · Nebraska · 2019

Unrated tornado, Berea to Nonpareil, Nebraska, September 20, 2019

Name: Unrated tornado, Berea to Nonpareil, Nebraska, September 20, 2019
Start: 2019-09-21T00:05:00.000Z
End: 2019-09-21T00:06:00.000Z
Location: Berea to Nonpareil, Nebraska

From Berea to Nonpareil, this Unrated tornado ran 10.3 miles across Box Butte County on September 20, 2019, touching down at 6:05 PM MDT and reaching 20 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
Unratedthis tornado
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.

The record

Rating: Unrated
Date: September 20, 2019
Touchdown: 6:05 PM MDT (00:05 UTC)
Lifted: 6:06 PM MDT (00:06 UTC)
On the ground: 1 minutes
Path length: 10.3 miles (16.5 km)
Path width: 20 yards (18 m)
Deaths: 0
Injuries: 0
County: Box Butte County
Touchdown point: 42.090, -103.190
Lift-off point: 42.090, -103.390
Record number: 1909201805-01

What the Weather Service recorded

Severe thunderstorms moved across the Nebraska Panhandle producing large hail from nickel size to golf ball size. In addition, a supercell thunderstorm with associated outflow boundaries produced several gustnadoes along the outflow. The supercell thunderstorm also produced a brief tornado with reports saying it remained on the ground for roughly 90 seconds for 10 miles. The tornado did not hit any structures or produce any damage to assign any other rating besides unknown. Tornado path width is also estimated given the lack of evidence.

Tornado was observed for roughly ninety seconds with several outflow gustnadoes reported near the parent supercell. No visible damage was noted making it impossible to discern an appropriate rating besides unknown.

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

What forecasters said that day

The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Cheyenne, WY wrote its last area forecast discussion before the tornado touched down at Sep 20, 5:35 PM MDT, 30 minutes earlier.

Area forecast discussion, Sep 20, 5:35 PM MDT, 30 minutes before

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Hazardous weather outlook, Sep 20, 4:11 PM MDT, 1 hour 54 minutes before

Hazardous Weather Outlook
National Weather Service Cheyenne WY
411 PM MDT Fri Sep 20 2019

NEZ002-003-019>021-054-055-095-096-WYZ101>103-106>108-117>119-
212215-
Dawes-Box Butte-Scotts Bluff-Banner-Morrill-Kimball-Cheyenne-
North Sioux-South Sioux-Converse County Lower Elevations-
Niobrara County-North Laramie Range-
Central Laramie Range and Southwest Platte County-
East Platte County-Goshen County-South Laramie Range Foothills-
Central Laramie County-East Laramie County-
411 PM MDT Fri Sep 20 2019

.DAY ONE...THIS AFTERNOON AND TONIGHT

...SEVERE THUNDERSTORM WATCH 655 IS IN EFFECT UNTIL 1 AM FOR THE
FOLLOWING COUNTIES

IN NEBRASKA THIS WATCH INCLUDES 5 COUNTIES

IN WESTERN NEBRASKA

BOX BUTTE             DAWES                 MORRILL
SCOTTS BLUFF          SIOUX

IN WYOMING THIS WATCH INCLUDES 2 COUNTIES

IN EAST CENTRAL WYOMING

NIOBRARA

IN SOUTHEAST WYOMING

GOSHEN

strong to severe thunderstorms are expected this afternoon and
evening with large hail and damaging winds the main threat. An
isolated tornado or two will also be possible across the far
northern Nebraska panhandle.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

Widespread hazardous weather is not expected.

.Spotter information statement...

Spotter activation will likely be needed tonight.

WYZ111-113-212215-
Southwest Carbon County-Upper North Platte River Basin-
411 PM MDT Fri Sep 20 2019

This hazardous weather outlook is for portions of south central
Wyoming.

.DAY ONE...THIS AFTERNOON AND TONIGHT

Cold overnight low temperatures are expected to bring freezing
conditions to interior valleys. Sensitive plants maybe killed by
frost.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

Widespread hazardous weather is not expected.

.Spotter information statement...

Spotter activation will not be needed.

WYZ104-105-109-110-112-114>116-212215-
Ferris/Seminoe/Shirley Mountains-Shirley Basin-
Central Carbon County-North Snowy Range Foothills-
Sierra Madre Range-Snowy Range-Laramie Valley-South Laramie Range-
411 PM MDT Fri Sep 20 2019

This hazardous weather outlook is for portions of south central
Wyoming and southeast Wyoming.

.DAY ONE...THIS AFTERNOON AND TONIGHT

Strong winds are likely across Arlington and Elk Mountain this
evening and overnight through early morning saturday. Light and
high profile vehicles may experience significant crosswinds along
I-80.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

Widespread hazardous weather is not expected.

.Spotter information statement...

Spotter activation will not be needed.

In the hours before

Special weather statement, Sep 20, 5:17 PM MDT, 48 minutes before

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Local storm report, Sep 20, 5:27 PM MDT, 38 minutes before

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Local storm report, Sep 20, 5:30 PM MDT, 35 minutes before

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Local storm report, Sep 20, 5:45 PM MDT, 20 minutes before

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Special weather statement, Sep 20, 5:46 PM MDT, 19 minutes before

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Local storm report, Sep 20, 5:52 PM MDT, 13 minutes before

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The air that afternoon

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.

Rapid City, SD (KUNR), 00:00Z

0.1 hours before the tornado, 223 km from the path. September 21, 2019.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.

Mixed-layer CAPE: 1201 J/kg
Mixed-layer CIN: -90 J/kg
Surface CAPE: 2222 J/kg
Mixed-layer LCL: 1361 m above ground
0-6 km bulk shear: 39 kt
0-1 km bulk shear: 18 kt
0-1 km storm-relative helicity: 125 m²/s²
0-3 km storm-relative helicity: 174 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.3
0-3 km lapse rate: 7.4 K/km

Open this sounding in Storm Lab

The surface observations

Scottsbluff (BFF), 35 km from the path, in the two hours either side.

Time (UTC)	Temp (°F)	Dew point (°F)	Wind	Gust (kt)	Pressure (mb)	Weather
00:00 UTC

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

The radar

The Cheyenne radar (KCYS), 164 km away, was scanning. The volume nearest the touchdown began at 00:05 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.

This ground now

The live radar over the track Every 2019 tornado in Nebraska Every tornado in Nebraska since 1950 Warnings in force in Nebraska now The forecast where you are

The other tornadoes of September 20, 2019

1 more were confirmed in the United States that day.

Date	Time	Rating	Where	Path (mi)	Width (yd)	Deaths	Injuries	Damage
September 20	6:00 PM CDT	EF0	Towner, ND	0.1	25

What this means

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.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.