Tornadoes · United States · Nebraska · 2011

EF0 tornado, Atkinson, Nebraska, May 30, 2011

Name: EF0 tornado, Atkinson, Nebraska, May 30, 2011
Start: 2011-05-30T22:05:00.000Z
End: 2011-05-30T22:08:00.000Z
Location: Atkinson, Nebraska

This EF0 tornado ran 0.0 miles across Holt County on May 30, 2011, touching down at 5:05 PM CDT 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 mphthis tornado
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.
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.

The record

Rating: EF0
Date: May 30, 2011
Touchdown: 5:05 PM CDT (22:05 UTC)
Lifted: 5:08 PM CDT (22:08 UTC)
On the ground: 3 minutes
Path length: 0.0 miles (0.0 km)
Path width: 20 yards (18 m)
Deaths: 0
Injuries: 0
County: Holt County
Touchdown point: 42.490, -98.980
Lift-off point: 42.490, -98.980
Record number: 1105301605-01

What the Weather Service recorded

A powerful low pressure system moved across western and north central Nebraska on Memorial Day. Thunderstorms developed along a cold front extending across central Nebraska. The storms tracked quickly northeast to produce hail up to 4 inches in diameter, damaging winds and several tornadoes.

Dispatcher reported tornado briefly touched down in open field where foliage debris extended east along Highway 11.

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

The warnings

18 minutes of warning. NWS LBF issued a tornado warning for this county at 21:47 UTC, 18 minutes before the tornado touched down, in force until 22:15 UTC.

The county was under a tornado watch, issued at 19:10 UTC and running to 02:00 UTC.

Issued (UTC)	Expired	Product	Office
15:00 UTC	23:22 UTC	Wind Advisory	LBF
15:00 UTC	08:57 UTC	High Wind Watch	LBF
19:10 UTC	02:00 UTC	Tornado Watch	LBF
21:47 UTC	22:15 UTC	Tornado Warning	LBF
22:10 UTC	22:45 UTC	Tornado Warning	LBF
22:43 UTC	23:15 UTC	Tornado Warning	LBF
22:46 UTC	23:15 UTC	Tornado Warning	LBF
23:11 UTC	00:00 UTC	Severe Thunderstorm Warning	LBF
23:40 UTC	00:15 UTC	Tornado Warning	LBF
23:54 UTC	00:15 UTC	Tornado Warning	LBF

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 forecast that day

The Storm Prediction Center had this point in a Moderate Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:51 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.

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 North Platte, NE wrote its last area forecast discussion before the tornado touched down at May 30, 2:32 PM CDT, 2 hours 33 minutes earlier.

Area forecast discussion, May 30, 2:32 PM CDT, 2 hours 33 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
232 PM CDT MON MAY 30 2011

.SYNOPSIS...
A TROUGH OF SURFACE LOW PRESSURE EXTENDS FORM SE COLORADO INTO
EASTERN SOUTH DAKOTA. DEEPEST LOW PRESSURE SHOULD FOCUS NEAR OR
SOUTH OF CUSTER COUNTY. TEMPS IN THE MID/UPPER 80S EAT OF SURFACE
FRONT...WHILE TO THE WEST MID 60S TO LOW 70S PREVAIL. LINE OF
TOWERING CUMULUS ALONG FRONTAL BOUNDARY EXTENDING FROM NEAR NORTH
PLATTE THROUGH BREWSTER...BASSETT AND SPRINGVIEW. STORMS JUST
INITIATING AT 1930Z. THIS IS A PRECURSOR TO SEVERE STORM DEVELOPMENT
THIS AFTERNOON/EVENING.

&&

.SHORT TERM DISCUSSION (THIS EVENING THROUGH THURSDAY NIGHT)...

THIS EVENING...SURFACE BASED STORMS LIKELY TO BE WELL ROOTED EAST OF
A LINE FROM NEAR BRADY THROUGH AINSWORTH AND SPRINGVIEW IN VICINITY
OF SFC FRONT STRETCHED ACROSS THE REGION. DISCRETE STORM MOTION
EARLY EVENING TO TRANSITION QUICKLY TO A SQUALL LINE AS COLD FRONT
GET STRONG PUSH FROM THE WEST. TRAINING STORM ECHOES LIFTING
NORTHEAST WILL POSE A RISK FOR FLASH FLOODING UNTIL LATE
EVENING...WHEN CONVECTION SHOULD EXIT FAR EASTERN COUNTIES. THERE IS
AN ENHANCED RISK FOR LARGE HAIL AND EVEN AN ISOLATED TORNADO OR TWO.
LOCATIONS WHERE A CORRIDOR OF BACKED LOW LEVEL FLOW NORTH OF MAIN
SURFACE LOW FORECAST IN CUSTER COUNTY SHOWED AREAS IN CUSTER COUNTY
AND COUNTIES TO THE NORTH AND NORTHEAST OF CUSTER COUNTY NORTHEAST
MOST AT RISK.

TUESDAY...DRY WITH BREEZY WEST WINDS AND A MAINLY SUNNY SKY AND MILD
TEMPS IN THE MID/UPPER 70S. DEWPOINTS LOWERING TO THE MID 30S/LOWER
40S WILL BRING AN INCREASED FIRE DANGER WITH LOWEST RH OF 20 TO 30
PERCENT.

TUESDAY NIGHT/WEDNESDAY/WEDNESDAY NIGHT...PRECIPITABLE WATER (PWS)
VALUES INCREASE TO 0.75 TO 1.25 INCHES BY 12Z WEDNESDAY. GFS/NAM IN
GOOD AGREEMENT WITH CONVECTION DEVELOPING LATE TUESDAY NIGHT ACROSS
SWRN NEBR. PWS INCREASE TO 1 TO 1.5 INCHES BY LATE WEDNESDAY
AFTERNOON. MODERATELY UNSTABLE WITH SBCAPES FROM 1500 TO 3500 J/KG.
HIGHS MID 80S TO NEAR 90. POTENTIAL FOR STRONGEST CONVECTION BY
EVENING AS BACKED LOW LEVEL FLOW TO INCREASE HELICITY VALUES FOR
ROTATING STORMS WITH DEEP LAYER SHEAR OF 35 TO 45 KTS.

THURSDAY/THURSDAY NIGHT...THURSDAY WILL LIKELY BE THE HOTTEST DAYS
IN THE NEXT 7 DAYS. UPPER RIDGE BREAK DOWN AS TROUGH MOVES INTO
INTERMOUNTAIN WEST. GOING HIGHS FROM 88 TO 95 LOOK APPROPRIATE.
THERE SHOULD BE AT LEAST ISOLATED STORMS POSSIBLE THURSDAY NIGHT.

.EXTENDED DISCUSSION (FRIDAY THROUGH MONDAY)...

AN UPPER TROUGH LIFTING ACROSS THE NORTHERN PLAINS WILL BRING A
COOLDOWN FRIDAY BEHIND A COLD FRONT. HIGHS WILL STILL MANAGE TO
REACH THE UPPER 70S NORTHWEST WITH MID 80S SOUTHEAST. UPPER RIDGE
WILL BUILD BACK INTO THE SRN/CNTRL PLAINS AND INTERMOUNTAIN REGION
THROUGH MONDAY IN RESPONSE TO A CLOSED LOW DIGGING INTO NRN
CALIFORNIA. A HEATUP AGAIN IN STORE BY SUNDAY WITH 85 TO 90 AND
UPPER 80/LOWER 90S POSSIBLE BY MONDAY.  MOISTURE TRAJECTORIES STILL
INDICATE MAINLY NOCTURNAL CONVECTION FAVORED THROUGH SATURDAY NIGHT
IN SWRLY FLOW ALOFT ACROSS NEW MEXICO NORTHEAST ACROSS COLORADO INTO
KANSAS. THIS PERIOD LOOKS DRY...ALTHOUGH ISOLATED STORMS POSSIBLE.

&&

.AVIATION...
MAINLY VFR CONDITIONS THE NEXT 24 HOURS. A COLD FRONT WILL PUSH
ACROSS THE REGION TONIGHT. NORTHWEST WINDS WILL BE INCREASING BEHIND
THE FRONT...HIGHEST ACROSS SOUTHWEST NEB...GUSTING ABOVE 20 KTS.
AHEAD OF THE FRONT...EARLY THIS EVENING...WILL BE A LINE OF STRONG
TO SEVERE THUNDERSTORMS. THIS LINE IS EXPECTED TO OCCUR EAST OF TAF
SITES...KLBF AND KVTN AND RACE TO THE NORTHEAST. EVERYTHING EXITS BY
MORNING WITH CLEAR VFR SKIES FOR TUESDAY.

&&

.HYDROLOGY...
WARM TEMPERATURES THIS WEEK IN THE ROCKIES WILL AID IN INCREASING
RUNOFF FROM SNOW MELT. THUS OVER THE NEXT COUPLE OF WEEKS THE SOUTH
PLATTE RIVER IS EXPECTED TO RISE...STILL REMAINING WELL BELOW FLOOD
STAGE. MEANWHILE...THE NORTH PLATTE...UPSTREAM OF LAKE
MCCONAUGHY...WILL REMAIN STEADY OR SLIGHTLY FALL UNTIL RELEASES
CHANGE FROM THE WYOMING RESERVOIRS. LAKE MCCONAUGHY WILL CONTINUE TO
INCREASE RELEASES THROUGHOUT THE WEEK...IN A STAIR STEP FASHION.
THIS WILL CAUSE THE NORTH PLATTE RIVER TO RISE OVER THE NEXT WEEK
AND A HALF. BY THURSDAY THE RIVER AT NORTH PLATTE IS EXPECTED TO BE
UP TO 8.0 FEET...WITH AN ADDITIONAL RISE TO 8.1 FEET BY SATURDAY.
FURTHER RISES TO 8.5 FEET BY NEXT WEDNESDAY...JUNE 8...IS
ANTICIPATED BASED ON PLANNED RELEASES FROM THE LAKE...HOWEVER THIS
PLANNED RELEASE SCHEDULE MAY BE ALTERED PENDING SNOW MELT IN THE
MOUNTAINS AND RELEASES FROM THE WYOMING RESERVOIRS.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY CONTINUES FOR
NEZ010-027>029-038-071 TIL 01Z.

&&

SHORT TERM/EXTENDED...ROBERG
AVIATION/HYDROLOGY...MASEK

Hazardous weather outlook, May 30, 4:43 PM CDT, 22 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
443 PM CDT MON MAY 30 2011

NEZ004>010-022>029-035>038-056>059-069>071-094-312145-
SHERIDAN-EASTERN CHERRY-KEYA PAHA-BOYD-BROWN-ROCK-HOLT-GARDEN-
GRANT-HOOKER-THOMAS-BLAINE-LOUP-GARFIELD-WHEELER-ARTHUR-MCPHERSON-
LOGAN-CUSTER-DEUEL-KEITH-PERKINS-LINCOLN-CHASE-HAYES-FRONTIER-
WESTERN CHERRY-
443 PM CDT MON MAY 30 2011 /343 PM MDT MON MAY 30 2011/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN AND
NORTH CENTRAL NEBRASKA.

.DAY ONE...TONIGHT.

SCATTERED SEVERE THUNDERSTORMS CAPABLE OF VERY LARGE HAIL...WIND
DAMAGE AND TORNADOES...PERHAPS ONE OR TWO STRONG...WILL MOVE
ALONG AND EAST OF HIGHWAY 83. STORM MOTION WILL BE NORTHEAST AT
30 TO 40 MPH. MEANWHILE A COLD FRONT WILL PUSH EAST ACROSS
WESTERN NEBRASKA THIS EVENING...WITH A CHANCE FOR SEVERE
THUNDERSTORMS. THE MAIN THREAT WITH THE WESTERN STORMS IS FOR
LARGE HAIL AND DAMAGING WINDS. THUNDERSTORMS ARE EXPECTED TO
DIMINISH AFTER MIDNIGHT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

SCATTERED SEVERE STORMS ARE POSSIBLE WEDNESDAY AFTERNOON AND
EVENING. THE AREA OF CONCERN IS GENERALLY ALONG AND EAST OF
HIGHWAY 83. A WARM FRONT IS EXPECTED TO LIFT NORTH INTO CENTRAL
NEBRASKA WITH STORM DEVELOPMENT LATE IN THE AFTERNOON DURING THE
PEAK HEATING PERIOD. WINDS ALOFT WILL BE STRONG FAVORING STORMS
CAPABLE OF LARGE HAIL AND WIND DAMAGE. STORM MOTION IS EXPECTED
TO BE NORTHEAST AT AROUND 25 MPH.

THURSDAY AND BEYOND...THE NORTH PLATTE RIVER AT NORTH PLATTE WILL
RISE TO 8.0 FEET PRODUCING RECORD FLOODING. WARM WEATHER IN THE
ROCKIES WILL PRODUCE RAPID SNOW MELT THIS WEEK INCREASING THE
RISK OF RISES ON THE NORTH PLATTE RIVER AT LISCO AND LEWELLEN.

DEEP TROPICAL MOISTURE WILL BEGIN AFFECTING THE CENTRAL PLAINS
FRIDAY THROUGH SUNDAY. AN APPROACHING STORM SYSTEM FROM THE WEST
COULD SPARK THUNDERSTORMS AND HEAVY RAIN DAILY. THE AREA OF
CONCERN IS SOUTHWEST NEBRASKA AND THE RISK OF FLASH FLOODING MAY
INCREASE NEXT WEEKEND.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS LIKELY THIS EVENING ALONG AND EAST OF
HIGHWAY 183. SPOTTER ACTIVATION IS ALSO POSSIBLE ELSEWHERE AS FAR
WEST AS HIGHWAY 83.

&&

THIS PRODUCT IS NOW AVAILABLE...ALONG WITH OTHER WEATHER...
HYDROLOGICAL AND CLIMATOLOGICAL INFORMATION...AT
HTTP://WWW.WEATHER.GOV/NORTHPLATTE

MASEK

In the hours before

Local storm report, May 30, 4:51 PM CDT, 14 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORTH PLATTE NE
451 PM CDT MON MAY 30 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0445 PM     HAIL             ROSE                    42.17N 99.53W
05/30/2011  M2.50 INCH       ROCK               NE   LAW ENFORCEMENT

            GOLF BALL TO TENNIS BALL SIZED HAIL COVERING GROUND.5

&&

CARMEL

Local storm report, May 30, 4:52 PM CDT, 13 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
452 PM CDT MON MAY 30 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0420 PM     TORNADO          3 E ROSE                42.17N 99.47W
05/30/2011                   ROCK               NE   STORM CHASER

            BRIEF TORNADO TOUCHDOWN REPORTED BY STORM CHASER 100 TO
            300 YARDS EAST OF HIGHWAY 183.

&&

CARMEL

Local storm report, May 30, 4:56 PM CDT, 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORTH PLATTE NE
456 PM CDT MON MAY 30 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0447 PM     TORNADO          3 E DUNNING             41.83N 100.05W
05/30/2011                   BLAINE             NE   STORM CHASER

            TORNADO REPORTED BY STORM CHASER. CONTINUED ROTATING WALL
            CLOUD WITH MULTIPLE FUNNELS ALSO REPORTED.

&&

CARMEL

Local storm report, May 30, 4:59 PM CDT, 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORTH PLATTE NE
459 PM CDT MON MAY 30 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0425 PM     HAIL             2 N ROSE                42.20N 99.53W
05/30/2011  M2.50 INCH       ROCK               NE   STORM CHASER

            DELAYED REPORT FROM STORM CHASER. 2 VEHICLES HAD
            WINDSHIELD DAMAGE FROM HAIL. ONE VEHICLE REAR WWINDOW
            BUSTED OUT. GROUND WAS COVERED BY HAIL.

&&

CARMEL

Local storm report, May 30, 5:00 PM CDT, 5 minutes before

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE NORTH PLATTE NE
500 PM CDT MON MAY 30 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0320 PM     HAIL             3 ENE BASSETT           42.60N 99.48W
05/30/2011  M0.50 INCH       ROCK               NE   PUBLIC

            PEA TO MARBLE SIZED HAIL LASTED 10 MINUTES BEGINNING AT
            320 PM CDT. ALSO REPORTED HEAVY RAIN.

0328 PM     HAIL             4 SE DUNNING            41.79N 100.05W
05/30/2011  M1.00 INCH       BLAINE             NE   PUBLIC

            BIGGEST HAIL THE SIZE OF QUARTERS ALONG WITH HEAVY RAIN.

0330 PM     HAIL             5 NE DUNNING            41.88N 100.04W
05/30/2011  M1.00 INCH       BLAINE             NE   PUBLIC

            NICKEL TO QUARTER SIZED HAIL AND HEAVY RAIN AT TIME OF
            REPORT NEAR HIGHWAY 91.

0352 PM     HAIL             7 NNE DUNNING           41.92N 100.05W
05/30/2011  M1.00 INCH       BLAINE             NE   PUBLIC

0401 PM     HAIL             BREWSTER                41.94N 99.87W
05/30/2011  M1.00 INCH       BLAINE             NE   LAW ENFORCEMENT

            PEA TO QUARTER SIZE HAIL REPORTED BY DISPATCHER. GROUND
            COVERED BY HAIL.

0410 PM     HAIL             6 E BASSETT             42.58N 99.42W
05/30/2011  M1.00 INCH       ROCK               NE   PUBLIC

            BIG MARBLES TO QUARTER SIZED HAIL WITH BRIEF DURATION.

0420 PM     HAIL             25 S LONG PINE          42.17N 99.70W
05/30/2011  M1.00 INCH       BROWN              NE   LAW ENFORCEMENT

            MARBLE TO QUARTER SIZED HAIL COVERING THE GROUND. VERY
            HEAVY RAIN ALSO REPORTED.

0420 PM     HAIL             ROSE                    42.17N 99.53W
05/30/2011  U1.25 INCH       ROCK               NE   LAW ENFORCEMENT

            WINDOWS BROKEN OUT OF HOME BY LARGE HAIL EXACT SIZE
            UNKNOWN AT THIS TIME.

0420 PM     TORNADO          3 E ROSE                42.17N 99.47W
05/30/2011                   ROCK               NE   STORM CHASER

            BRIEF TORNADO TOUCHDOWN REPORTED BY STORM CHASER 100 TO
            300 YARDS EAST OF HIGHWAY 183.

0425 PM     HAIL             2 N ROSE                42.20N 99.53W
05/30/2011  M2.50 INCH       ROCK               NE   STORM CHASER

            DELAYED REPORT FROM STORM CHASER. 2 VEHICLES HAD
            WINDSHIELD DAMAGE FROM HAIL. ONE VEHICLE REAR WWINDOW
            BUSTED OUT. GROUND WAS COVERED BY HAIL.

0445 PM     HAIL             ROSE                    42.17N 99.53W
05/30/2011  M2.50 INCH       ROCK               NE   LAW ENFORCEMENT

            GOLF BALL TO TENNIS BALL SIZED HAIL COVERING GROUND.5

0447 PM     TORNADO          3 E DUNNING             41.83N 100.05W
05/30/2011                   BLAINE             NE   STORM CHASER

            TORNADO REPORTED BY STORM CHASER. CONTINUED ROTATING WALL
            CLOUD WITH MULTIPLE FUNNELS ALSO REPORTED.

&&

CARMEL

Local storm report, May 30, 5:05 PM CDT, 0 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORTH PLATTE NE
505 PM CDT MON MAY 30 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0500 PM     HAIL             6 SW ATKINSON           42.47N 99.06W
05/30/2011  M2.75 INCH       HOLT               NE   LAW ENFORCEMENT

            BASEBALL SIZED HAIL 6 MILES SOUTHWEST OF ATKINSON.

&&

CARMEL

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.

N. Platte/Lee Bi, NE (KLBF), 12:00Z

10.1 hours before the tornado, 202 km from the path. May 30, 2011.

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: 1099 J/kg
Mixed-layer CIN: -360 J/kg
Surface CAPE: 941 J/kg
Mixed-layer LCL: 2078 m above ground
0-6 km bulk shear: 38 kt
0-1 km bulk shear: 38 kt
0-1 km storm-relative helicity: 296 m²/s²
0-3 km storm-relative helicity: 302 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0
0-3 km lapse rate: 5.3 K/km

Open this sounding in Storm Lab

N. Platte/Lee Bi, NE (KLBF), 00:00Z

1.9 hours after it, 202 km from the path. May 31, 2011.

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

Mixed-layer CAPE: 634 J/kg
Mixed-layer CIN: -231 J/kg
Surface CAPE: 2342 J/kg
Mixed-layer LCL: 2144 m above ground
0-6 km bulk shear: 79 kt
0-1 km bulk shear: 20 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 144 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -1.1
0-3 km lapse rate: 7.5 K/km

Open this sounding in Storm Lab

The surface observations

O Neill (ONL), 24 km from the path, in the two hours either side.

Time (UTC)	Temp (°F)	Dew point (°F)	Wind	Gust (kt)	Pressure (mb)	Weather
20:15 UTC	86	62.6	180° 21 kt	32	998.3
20:35 UTC	87.8	64.4	170° 23 kt	28	998.3
20:55 UTC	86	64.4	170° 20 kt	31	997.6
21:15 UTC	86	64.4	170° 19 kt	27	997.6
21:35 UTC	84.2	64.4	160° 19 kt	30	997	VCTS
21:55 UTC	82.4	64.4	160° 20 kt	29	996.6	VCTS
22:15 UTC	82.4	62.6	150° 27 kt	34	995.9	TS
22:35 UTC	71.6	59	330° 11 kt	24	998.3	TS
22:55 UTC	69.8	60.8	360° 3 kt		997
23:15 UTC	75.2	62.6	120° 6 kt		995.9	VCTS
23:35 UTC	69.8	60.8	320° 9 kt	16	996.6	TS
23:55 UTC	64.4	60.8	20° 12 kt	17	997.3	+TSRA

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

The radar

The North Platte radar (KLNX), 144 km away, was scanning. The volume nearest the touchdown began at 22:06 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)	Report	Where	County	Remark
20:20 UTC	HAIL 0.5	3 Ene Bassett	Rock, NE	PEA TO MARBLE SIZED HAIL LASTED 10 MINUTES BEGINNING AT 320 PM CDT. ALSO REPORTED HEAVY RAIN.
21:10 UTC	HAIL 1	6 E Bassett	Rock, NE	BIG MARBLES TO QUARTER SIZED HAIL WITH BRIEF DURATION.
21:20 UTC	HAIL 1.25	Rose	Rock, NE	WINDOWS BROKEN OUT OF HOME BY LARGE HAIL EXACT SIZE UNKNOWN AT THIS TIME.
21:20 UTC	TORNADO	3 E Rose	Rock, NE	BRIEF TORNADO TOUCHDOWN REPORTED BY STORM CHASER 100 TO 300 YARDS EAST OF HIGHWAY 183.
21:25 UTC	HAIL 2.5	2 N Rose	Rock, NE	DELAYED REPORT FROM STORM CHASER. 2 VEHICLES HAD WINDSHIELD DAMAGE FROM HAIL. ONE VEHICLE REAR WWINDOW BUSTED OUT. GROUND WAS COVERED BY HAIL.
21:35 UTC	HAIL 2.75	22 S Newport	Rock, NE
21:35 UTC	TORNADO	1 E Rose	Rock, NE	BRIEF TORNADO TOUCHDOWN REPORTED BY STORM CHASER.
21:44 UTC	TORNADO	3 E Rose	Rock, NE	BRIEF TORNADO TOUCHDOWN REPORTED BY STORM CHASER 100 TO 300 YARDS EAST OF HIGHWAY 183.
21:45 UTC	HAIL 2.5	Rose	Rock, NE	GOLF BALL TO TENNIS BALL SIZED HAIL COVERING GROUND.5
22:00 UTC	HAIL 2.75	6 Sw Atkinson	Holt, NE	BASEBALL SIZED HAIL 6 MILES SOUTHWEST OF ATKINSON.
22:05 UTC	TORNADO	3 S Atkinson	Holt, NE	DISPATCHER RELAYED REPORT OF TORNADO 3 MILES SOUTH OF ATKINSON. LOTS OF DEBRIS REPORTED ALONG HIGHWAY 11.
22:10 UTC	HAIL 1	1 E Naper	Boyd, NE
22:10 UTC	HAIL 2.75	Atkinson	Holt, NE	BASEBALL SIZED HAIL FALLING 1 MILE SOUTH OF ATKINSON ON HIGHWAY 11.
22:10 UTC	HAIL 4	Atkinson	Holt, NE	AT LEAST GRAPEFRUIT SIZE HAIL REPORTED IN THE CENTER OF ATKINSON. TIME OF REPORT WAS 510 PM CDT.
22:11 UTC	HAIL 2.75	Atkinson	Holt, NE	BASEBALL SIZE HAIL FALLING IN SOUTHWEST PART OF ATKINSON.
22:12 UTC	HAIL 2.75	3 N Rose	Rock, NE	REPORT OF MANY HAIL STONES OVER 1 INCH WITH A THIRD OF HAIL STONES OVER ONE AND THREE QUARTER INCH IN DIAMETER. LARGEST HAIL STONES WERE BASEBALL SIZED...AFTER MELTING AS REPORTED BY STORM CHASER.
22:13 UTC	HAIL 1.75	2 Se Stuart	Holt, NE	GOLF BALL SIZE HAIL FALLING JUST SOUTHEAST OF STUART AS REPORTED BY DEPUTIES.
22:13 UTC	HAIL 2.75	Atkinson	Holt, NE	BASEBALL HAIL FALLING AT COUNTRY CLUB AND ELSEWHERE IN ATKINSON.
22:16 UTC	HAIL 2	3 Ne Atkinson	Holt, NE
22:17 UTC	HAIL 4	3 Ese Atkinson	Holt, NE	NEARLY GRAPEFRUIT SIZE HAIL SIZE MEASURED BY STORM CHASER. ACTUAL DIAMETER OF STONE WAS 3.5 INCHES.
22:30 UTC	TORNADO	5 N Atkinson	Holt, NE	DEPUTIES REPORT 3 TORNADOES ON THE GROUND. 873RD ROAD AND 487TH AVENUE IS APPROXIMATE LOCATION OF REPORT.
22:30 UTC	TORNADO	5 N Oneill	Holt, NE	DEPUTIES REPORT 3 TORNADOES ON THE GROUND. 873RD ROAD AND 487TH AVENUE IS APPROXIMATE LOCATION OF REPORT.
23:26 UTC	HAIL 1.75	1 Sw Atkinson	Holt, NE
23:26 UTC	HAIL 1.75	Atkinson	Holt, NE	COOPERATIVE OBSERVER REPORTED GOLF BALL SIZED HAIL IN ATKINSON.
23:33 UTC	TORNADO	4 N Oneill	Holt, NE	LOTS OF ROTATION. SEVERAL FUNNELS REPORTED BY STORM CHASER. ONE BRIEF TORNADO TOUCHDOWN AND SAW A POWER FLASH.
23:39 UTC	HAIL 0.88	Emmet	Holt, NE	NICKEL SIZED HAIL FELL FOR A FOUR MINUTE PERIOD.
23:40 UTC	TORNADO	2 Ne Oneill	Holt, NE	2 TORNADOES ON THE GROUND 2 MILES NORTHEAST OF ONEILL AS REPORTED BY THE FIRE CHIEF.
23:50 UTC	TORNADO	6 Se Atkinson	Holt, NE	STORM CHASER ESTIMATES TORNADO 1/8 MILE WIDE. LOCATION WAS ALONG OLD HIGHWAY 20 AND HIGHWAY 281.
23:52 UTC	TORNADO	Oneill	Holt, NE	2 TORNADOES CONFIRMED ON EASTERN EDGE OF ONEILL BY POLICE CHIEF AND DEPUTY AND RELAYED BY DISPATCH. NO DAMAGE REPORTS THUS FAR.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the track Every 2011 tornado in Nebraska Every tornado in Nebraska since 1950 Warnings in force in Nebraska now The forecast where you are

The other tornadoes of May 30, 2011

15 more were confirmed in the United States that day.

Date	Time	Rating	Where	Path (mi)	Width (yd)	Damage
May 30	3:04 PM MDT	EF0	Adams, CO	0.1	50
May 30	4:20 PM CDT	EF0	Rock, NE	0.0	20
May 30	4:47 PM CDT	EF0	Blaine, NE	0.0	20
May 30	6:26 PM CDT	EF0	Charles Mix, SD	0.5	50
May 30	6:52 PM CDT	EF0	Holt, NE	0.0	20
May 30	7:34 PM CDT	EF0	Dawson, NE	0.4	25
May 30	8:12 PM CDT	EF0	Lake, SD	0.7	50
May 30	8:22 PM CDT	EF0	Lake, SD	0.5	50
May 30	8:46 PM CDT	EF2	Richland, ND	4.3	600	$550,000
May 30	8:52 PM CDT	EF1	Cass, ND	2.3	150	$250,000
May 30	8:55 PM CDT	EF2	Cass, ND	4.0	400	$600,000
May 30	9:01 PM CDT	EF1	Clay, MN	4.5	200	$250,000
May 30	9:03 PM CDT	EF2	Cass, ND	7.4	600	$750,000
May 30	9:26 PM CDT	EF1	Polk, MN	9.0	100	$50,000
May 30	10:35 PM CDT	EF1	Hubbard, MN	6.0	300	$600,000

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.