Alert archive / Nebraska / Tornado Watches in 2011

Tornado Watch 862

October 7, 201130 counties in Nebraska

The Storm Prediction Center issued this tornado watch at Oct 7, 2011, 6:45 PM CDT for 30 counties in Nebraska. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Oct 7, 2011, 6:45 PM CDT (23:45 UTC)
Expired
Oct 8, 2011, 2:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 30 counties

Adams County, NE, Antelope County, NE, Boone County, NE, Buffalo County, NE, Colfax County, NE, Custer County, NE, Dawson County, NE, Franklin County, NE, Frontier County, NE, Furnas County, NE, Gosper County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Howard County, NE, Kearney County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Phelps County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Sherman County, NE, Stanton County, NE, Valley County, NE, Wayne County, NE, Wheeler County, NE, York County, NE

The radar

The Grand Island radar (KUEX), 112 km from the middle of the area, began a volume at 23:45 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Oct 7, 7:05 PM CDTSevere Thunderstorm WarningGIDFurnas, Gosper, Harlan, Phelps40 min
Oct 7, 7:25 PM CDTSevere Thunderstorm WarningOAXAntelope, Knox, Pierce50 min
Oct 7, 7:33 PM CDTSevere Thunderstorm WarningGIDBuffalo, Greeley, Hall, Howard, Sherman, Valley29 min
Oct 7, 7:41 PM CDTSevere Thunderstorm WarningGIDBuffalo, Kearney, Phelps49 min
Oct 7, 7:53 PM CDTTornado WarningGIDBuffalo, Kearney, Phelps37 min
Oct 7, 8:43 PM CDTSevere Thunderstorm WarningGIDBuffalo, Kearney, Phelps32 min
Oct 7, 9:46 PM CDTSevere Thunderstorm WarningGIDBuffalo, Hall, Howard, Sherman44 min
Oct 7, 11:29 PM CDTSevere Thunderstorm WarningGIDFurnas, Harlan31 min
Oct 7, 11:35 PM CDTSevere Thunderstorm WarningLBFCuster, Lincoln, Logan40 min
Oct 8, 12:14 AM CDTSevere Thunderstorm WarningLBFCuster, Loup61 min
Oct 8, 12:24 AM CDTSevere Thunderstorm WarningGIDAdams, Buffalo, Hall, Kearney, Phelps36 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 11.8 hours before the alert went out and 154 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, N. Platte/Lee Bi, NE at 12:00Z on 2011-10-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, N. Platte/Lee Bi, NE at 12:00Z on 2011-10-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2787 m above ground
0-6 km bulk shear
91 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
111 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

851 
WWUS20 KWNS 072347
SEL2
SPC WW 072347
NEZ000-080500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 862
NWS STORM PREDICTION CENTER NORMAN OK
645 PM CDT FRI OCT 7 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

       SOUTH CENTRAL AND EAST CENTRAL NEBRASKA

EFFECTIVE THIS FRIDAY NIGHT FROM 645 PM UNTIL MIDNIGHT CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 45 STATUTE
MILES EAST AND WEST OF A LINE FROM 35 MILES WEST NORTHWEST OF
NORFOLK NEBRASKA TO 55 MILES SOUTH SOUTHWEST OF KEARNEY NEBRASKA.
 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU2).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 861...

DISCUSSION...TO THE IMMEDIATE EAST OF A NORTHEAST-SOUTHWEST ORIENTED
FRONTAL BOUNDARY...SCATTERED STRONG/SEVERE TSTMS ARE LIKELY TO
CONTINUE TO DEVELOP/QUICKLY MOVE NORTHEASTWARD THIS EVENING ACROSS
PORTIONS OF CENTRAL/EASTERN NEB. WHILE THE BOUNDARY LAYER IS NOT
STRONGLY UNSTABLE...STRENGTHENING DEEP LAYER/LOW LEVEL SHEAR THIS
EVENING WILL SUPPORT EMBEDDED/TRANSIENT SUPERCELLS. A FEW TORNADOES
COULD OCCUR MAINLY THROUGH EARLY/MID EVENING...WITH SEVERE HAIL/WIND
POSSIBLE AS WELL.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 23035.


...GUYER/THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 6, 8:29 PM CDTSevere Thunderstorm WatchSPCDundy, Hitchcock, Red Willow5 hr
Oct 6, 8:45 PM CDTMesoscale DiscussionSPCArthur, Cherry, Garden, Grant, Hooker, Logan and 2 more90 min
Oct 6, 11:08 PM CDTMesoscale DiscussionSPCFrontier, Furnas, Red Willow97 min
Oct 7, 12:42 AM CDTMesoscale DiscussionSPCAdams, Franklin, Furnas, Harlan, Kearney, Phelps and 1 more93 min
Oct 7, 2:24 PM CDTMesoscale DiscussionSPCAdams, Antelope, Boone, Buffalo, Cedar, Clay and 21 more96 min
Oct 7, 6:33 PM CDTTornado WatchSPCHitchcock, Red Willow7 hr

Nearby

Tornado Watches in Nebraska, 2011Every tornado watch in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.