Alert archive / Nebraska / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 741

August 7, 2011Ida County, Woodbury County, Iowa; 66 counties in Nebraska; 6 counties in South Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Aug 7, 2011, 7:49 PM CDT for Ida County, Woodbury County, Iowa; 66 counties in Nebraska; 6 counties in South Dakota. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Aug 7, 2011, 7:49 PM CDT (00:49 UTC)
Expired
Aug 8, 2011, 3:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
70 kt
All 74 counties

Ida County, IA, Woodbury County, IA, Adams County, NE, Antelope County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Buffalo County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Cherry County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Custer County, NE, Dakota County, NE, Dawson County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Gage County, NE, Garfield County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Holt County, NE, Hooker County, NE, Howard County, NE, Jefferson County, NE, Johnson County, NE, Kearney County, NE, Keya Paha County, NE, Knox County, NE, Lancaster County, NE, Logan County, NE, Loup County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Pawnee County, NE, Phelps County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Richardson County, NE, Rock County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Thayer County, NE, Thomas County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Webster County, NE, Wheeler County, NE, York County, NE, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Gregory County, SD, Union County, SD, Yankton County, SD

The radar

The North Platte radar (KLNX), 102 km from the middle of the area, began a volume at 00:53 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
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
95%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 7, 8:10 PM CDTSevere Thunderstorm WarningLBFBrown, Cherry, Keya Paha, Rock50 min
Aug 7, 8:12 PM CDTSevere Thunderstorm WarningGIDBuffalo, Hall, Howard, Sherman33 min
Aug 7, 8:49 PM CDTSevere Thunderstorm WarningLBFBoyd, Brown, Holt, Keya Paha, Rock56 min
Aug 7, 9:34 PM CDTSevere Thunderstorm WarningLBFBoyd, Garfield, Holt, Keya Paha, Rock, Wheeler56 min
Aug 7, 9:39 PM CDTSevere Thunderstorm WarningFSDBon Homme, Charles Mix, Gregory66 min
Aug 7, 9:46 PM CDTSevere Thunderstorm WarningOAXAntelope, Boone, Cedar, Knox, Madison, Pierce44 min
Aug 7, 10:25 PM CDTSevere Thunderstorm WarningOAXAntelope, Boone, Cedar, Knox, Madison, Pierce and 2 more50 min
Aug 7, 10:33 PM CDTSevere Thunderstorm WarningFSDDakota, Dixon57 min
Aug 7, 10:58 PM CDTSevere Thunderstorm WarningOAXBurt, Cedar, Cuming, Madison, Stanton, Thurston and 1 more47 min
Aug 7, 11:10 PM CDTFlash Flood WarningFSDWoodbury80 min
Aug 7, 11:12 PM CDTSevere Thunderstorm WarningFSDPlymouth, Woodbury48 min
Aug 7, 11:52 PM CDTSevere Thunderstorm WarningFSDIda, Woodbury38 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 00:00Z, 0.8 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 00:00Z on 2011-08-08Temperature 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 00:00Z on 2011-08-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 359 square meters per square second.19395878Sfc1 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
2434 m above ground
0-6 km bulk shear
67 kt
0-1 km storm-relative helicity
359 m²/s²
0-3 km storm-relative helicity
467 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 7, 10:28 PM CDTMesoscale DiscussionSPCAudubon, Calhoun, Carroll, Cass, Cherokee, Crawford and 10 more2 hr
Aug 7, 11:34 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Audubon, Calhoun, Carroll, Cass and 15 more4 hr
Aug 8, 1:06 PM CDTMesoscale DiscussionSPCBenton, Cedar, Clinton, Des Moines, Dubuque, Henry and 11 more84 min
Aug 8, 2:41 AM CDTMesoscale DiscussionSPCAdams, Buffalo, Butler, Cass, Clay, Fillmore and 23 more34 min
Aug 8, 3:09 PM CDTMesoscale DiscussionSPCArthur, Blaine, Box Butte, Custer, Dawes, Garden and 11 more66 min
Aug 8, 4:52 PM CDTSevere Thunderstorm WatchSPCArthur, Box Butte, Chase, Cherry, Cheyenne, Dawes and 19 more6 hr
Aug 8, 6:27 PM CDTMesoscale DiscussionSPCArthur, Box Butte, Chase, Cheyenne, Dawes, Dawson and 21 more2 hr
Aug 8, 6:44 PM CDTSevere Thunderstorm WatchSPCDawson, Furnas, Gosper, Harlan, Phelps4 hr

Nearby

Severe Thunderstorm Watches in Nebraska, 2011Severe Thunderstorm Watches in South Dakota, 2011Severe Thunderstorm Watches in Iowa, 2011Every severe thunderstorm 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.