Alert archive / Nebraska / Severe Thunderstorm Watches in 2007

Severe Thunderstorm Watch 563

August 4, 200718 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at Aug 4, 2007, 5:46 PM CDT for 18 counties in Nebraska. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Aug 4, 2007, 5:46 PM CDT (22:46 UTC)
Expired
Aug 4, 2007, 9:35 PM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Blaine County, NE, Buffalo County, NE, Custer County, NE, Dawson County, NE, Frontier County, NE, Garfield County, NE, Gosper County, NE, Greeley County, NE, Howard County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, Merrick County, NE, Nance County, NE, Polk County, NE, Sherman County, NE, Valley County, NE, Wheeler County, NE

The radar

The North Platte radar (KLNX), 100 km from the middle of the area, began a volume at 22:50 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
5%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
40%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
40%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 4, 6:06 PM CDTSevere Thunderstorm WarningLBFCuster39 min
Aug 4, 6:56 PM CDTSevere Thunderstorm WarningLBFCuster49 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, 10.8 hours before the alert went out and 72 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 2007-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 41 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 2007-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 130 square meters per square second.193958Sfc1 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
41 J/kg
Mixed-layer CIN
-331 J/kg
Mixed-layer LCL
1432 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
130 m²/s²
0-3 km storm-relative helicity
104 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 3, 8:02 PM CDTMesoscale DiscussionSPCAntelope, Blaine, Boyd, Brown, Cherry, Garfield and 8 more118 min
Aug 4, 1:49 AM CDTMesoscale DiscussionSPCBurt, Cedar, Cuming, Dakota, Dixon, Knox and 2 more86 min
Aug 4, 2:51 PM CDTMesoscale DiscussionSPCAntelope, Boone, Burt, Cedar, Cuming, Dakota and 13 more114 min
Aug 4, 3:55 PM CDTSevere Thunderstorm WatchSPCAntelope, Boone, Burt, Butler, Cass, Cedar and 18 more6 hr
Aug 4, 5:06 PM CDTMesoscale DiscussionSPCChase, Custer, Dawson, Dundy, Frontier, Garfield and 12 more114 min
Aug 4, 6:09 PM CDTMesoscale DiscussionSPCBurt, Cass, Cedar, Colfax, Cuming, Dakota and 13 more66 min

Nearby

Severe Thunderstorm Watches in Nebraska, 2007Every severe thunderstorm watch in 2007

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.