Alert archive / Nebraska / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 629

July 11, 201111 counties in Nebraska; 6 counties in South Dakota; 5 counties in Wyoming

The Storm Prediction Center issued this severe thunderstorm watch at Jul 11, 2011, 2:07 PM MDT for 11 counties in Nebraska; 6 counties in South Dakota; 5 counties in Wyoming. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jul 11, 2011, 2:07 PM MDT (20:07 UTC)
Expired
Jul 11, 2011, 9:00 PM MDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 22 counties

Banner County, NE, Box Butte County, NE, Cheyenne County, NE, Dawes County, NE, Deuel County, NE, Garden County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE, Butte County, SD, Custer County, SD, Fall River County, SD, Lawrence County, SD, Meade County, SD, Pennington County, SD, Campbell County, WY, Crook County, WY, Goshen County, WY, Niobrara County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 119 km from the middle of the area, began a volume at 20:07 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
30%
One or more gusts of 65 knots or more
10%
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
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 11, 2:38 PM MDTSevere Thunderstorm WarningCYSNiobrara41 min
Jul 11, 2:42 PM MDTSevere Thunderstorm WarningUNRCrook19 min
Jul 11, 3:16 PM MDTSevere Thunderstorm WarningCYSNiobrara29 min
Jul 11, 3:19 PM MDTSevere Thunderstorm WarningLBFSheridan56 min
Jul 11, 3:31 PM MDTSevere Thunderstorm WarningCYSDawes59 min
Jul 11, 3:44 PM MDTTornado WarningCYSSioux46 min
Jul 11, 4:04 PM MDTFlash Flood WarningLBFSheridan6 hr
Jul 11, 4:12 PM MDTSevere Thunderstorm WarningLBFSheridan63 min
Jul 11, 4:14 PM MDTSevere Thunderstorm WarningUNRFall River61 min
Jul 11, 4:24 PM MDTSevere Thunderstorm WarningCYSSioux51 min
Jul 11, 5:08 PM MDTSevere Thunderstorm WarningCYSDawes, Sioux26 min
Jul 11, 5:14 PM MDTSevere Thunderstorm WarningLBFCherry, Sheridan61 min
Jul 11, 5:59 PM MDTSevere Thunderstorm WarningCYSCheyenne, Morrill39 min
Jul 11, 6:14 PM MDTSevere Thunderstorm WarningLBFCherry, Sheridan61 min
Jul 11, 7:23 PM MDTSevere Thunderstorm WarningLBFDeuel67 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

Rapid City, SD (KUNR), launched 12:00Z, 8.1 hours before the alert went out and 112 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, Rapid City, SD at 12:00Z on 2011-07-11Temperature 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, Rapid City, SD at 12:00Z on 2011-07-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -49 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
1860 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-49 m²/s²
0-3 km storm-relative helicity
74 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
Jul 10, 6:21 PM MDTMesoscale DiscussionSPCAdams, Blaine, Brown, Buffalo, Chase, Custer and 29 more84 min
Jul 10, 6:24 PM MDTSevere Thunderstorm WatchSPCAdams, Blaine, Boyd, Brown, Buffalo, Chase and 38 more6 hr
Jul 10, 9:27 PM MDTMesoscale DiscussionSPCAntelope, Boone, Buffalo, Burt, Butler, Cedar and 27 more63 min
Jul 10, 9:57 PM MDTSevere Thunderstorm WatchSPCAntelope, Boone, Burt, Butler, Cedar, Colfax and 14 more4 hr
Jul 10, 10:56 PM MDTSevere Thunderstorm WatchSPCDakota, Dixon4 hr
Jul 11, 1:50 PM MDTMesoscale DiscussionSPCArthur, Banner, Box Butte, Cheyenne, Dawes, Deuel and 8 more85 min
Jul 11, 4:01 PM MDTMesoscale DiscussionSPCCherry, Dawes, Sheridan29 min
Jul 11, 4:06 PM MDTTornado WatchSPCBox Butte, Cherry, Dawes, Sheridan, Sioux5 hr

Nearby

Severe Thunderstorm Watches in Nebraska, 2011Severe Thunderstorm Watches in South Dakota, 2011Severe Thunderstorm Watches in Wyoming, 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.