Alert archive / Nebraska / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 764

August 10, 20114 counties in Colorado; 24 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at Aug 10, 2011, 4:03 PM MDT for 4 counties in Colorado; 24 counties in Nebraska. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Aug 10, 2011, 4:03 PM MDT (22:03 UTC)
Expired
Aug 10, 2011, 10:00 PM MDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 28 counties

Logan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Arthur County, NE, Banner County, NE, Box Butte County, NE, Chase County, NE, Cherry County, NE, Cheyenne County, NE, Dawes County, NE, Deuel County, NE, Frontier County, NE, Garden County, NE, Grant County, NE, Hayes County, NE, Hooker County, NE, Keith County, NE, Kimball County, NE, Lincoln County, NE, Logan County, NE, McPherson County, NE, Morrill County, NE, Perkins County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE, Thomas County, NE

The radar

The North Platte radar (KLNX), 163 km from the middle of the area, began a volume at 22:03 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
10%
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
50%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 10, 4:09 PM MDTSevere Thunderstorm WarningBOULogan, Weld51 min
Aug 10, 4:11 PM MDTTornado WarningCYSKimball49 min
Aug 10, 4:31 PM MDTSevere Thunderstorm WarningLBFCherry59 min
Aug 10, 5:05 PM MDTSevere Thunderstorm WarningBOULogan, Weld55 min
Aug 10, 5:23 PM MDTSevere Thunderstorm WarningCYSMorrill53 min
Aug 10, 5:24 PM MDTSevere Thunderstorm WarningLBFCherry51 min
Aug 10, 5:45 PM MDTSevere Thunderstorm WarningBOUSedgwick60 min
Aug 10, 5:57 PM MDTSevere Thunderstorm WarningBOULogan, Washington46 min
Aug 10, 5:57 PM MDTSevere Thunderstorm WarningLBFCherry63 min
Aug 10, 6:10 PM MDTSevere Thunderstorm WarningCYSKimball24 min
Aug 10, 6:13 PM MDTSevere Thunderstorm WarningBOULogan, Weld38 min
Aug 10, 6:21 PM MDTTornado WarningLBFCherry24 min
Aug 10, 6:40 PM MDTSevere Thunderstorm WarningBOULogan, Washington65 min
Aug 10, 6:41 PM MDTSevere Thunderstorm WarningBOUSedgwick27 min
Aug 10, 6:47 PM MDTSevere Thunderstorm WarningBOULogan40 min
Aug 10, 6:55 PM MDTSevere Thunderstorm WarningLBFCherry50 min
Aug 10, 7:24 PM MDTSevere Thunderstorm WarningBOULogan55 min
Aug 10, 7:44 PM MDTSevere Thunderstorm WarningLBFCherry, Hooker46 min
Aug 10, 8:29 PM MDTSevere Thunderstorm WarningLBFHooker, McPherson46 min
Aug 10, 9:15 PM MDTSevere Thunderstorm WarningLBFMcPherson30 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, 10.1 hours before the alert went out and 188 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 2011-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 23 joules per kilogram.LCLLFCEL10008507005003002001001 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 2011-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 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
23 J/kg
Mixed-layer CIN
-97 J/kg
Mixed-layer LCL
851 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
-64 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 9, 8:26 PM MDTMesoscale DiscussionSPCLogan, Morgan, Phillips, Sedgwick, Washington, Weld and 1 more64 min
Aug 9, 8:51 PM MDTSevere Thunderstorm WatchSPCCheyenne, Kit Carson, Logan, Phillips, Sedgwick, Washington and 1 more7 hr
Aug 10, 3:42 PM MDTMesoscale DiscussionSPCLogan, Phillips, Sedgwick63 min
Aug 10, 5:54 PM MDTMesoscale DiscussionSPCCheyenne, Kit Carson, Logan, Phillips, Sedgwick, Washington and 1 more66 min
Aug 10, 2:53 AM MDTMesoscale DiscussionSPCChase, Dundy, Frontier, Hayes, Hitchcock, Lincoln and 2 more67 min

Nearby

Severe Thunderstorm Watches in Nebraska, 2011Severe Thunderstorm Watches in Colorado, 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.