Alert archive / Nebraska / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 781

August 14, 20117 counties in Colorado; 7 counties in Kansas; 27 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at Aug 14, 2011, 2:29 PM MDT for 7 counties in Colorado; 7 counties in Kansas; 27 counties in Nebraska. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Aug 14, 2011, 2:29 PM MDT (20:29 UTC)
Expired
Aug 14, 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 41 counties

Cheyenne County, CO, Kit Carson County, CO, Logan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Yuma County, CO, Cheyenne County, KS, Decatur County, KS, Rawlins County, KS, Sheridan County, KS, Sherman County, KS, Thomas County, KS, Wallace County, KS, 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, Dundy County, NE, Frontier County, NE, Garden County, NE, Grant County, NE, Hayes County, NE, Hitchcock 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, Red Willow County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE, Thomas County, NE

The radar

The North Platte radar (KLNX), 181 km from the middle of the area, began a volume at 20:28 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
30%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 14, 3:39 PM MDTSevere Thunderstorm WarningBOULogan, Morgan, Weld32 min
Aug 14, 5:16 PM MDTSevere Thunderstorm WarningBOULogan29 min
Aug 14, 6:00 PM MDTSevere Thunderstorm WarningGLDYuma60 min
Aug 14, 6:59 PM MDTSevere Thunderstorm WarningGLDCheyenne46 min
Aug 14, 7:10 PM MDTSevere Thunderstorm WarningLBFArthur, Keith, McPherson50 min
Aug 14, 7:32 PM MDTSevere Thunderstorm WarningGLDYuma58 min
Aug 14, 7:45 PM MDTSevere Thunderstorm WarningGLDCheyenne, Rawlins38 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

Denver, CO (KDNR), launched 12:00Z, 8.5 hours before the alert went out and 173 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, Denver, CO at 12:00Z on 2011-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 249 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, Denver, CO at 12:00Z on 2011-08-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 16 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
249 J/kg
Mixed-layer CIN
-409 J/kg
Mixed-layer LCL
1695 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
16 m²/s²
0-3 km storm-relative helicity
-26 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 14, 1:59 PM MDTMesoscale DiscussionSPCAdams, Arapahoe, Cheyenne, Crowley, Elbert, El Paso and 9 more91 min

Nearby

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