Alert archive / Nebraska / Severe Thunderstorm Watches in 2007

Severe Thunderstorm Watch 535

July 18, 200715 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at Jul 18, 2007, 6:05 PM CDT for 15 counties in Nebraska. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jul 18, 2007, 6:05 PM CDT (23:05 UTC)
Expired
Jul 18, 2007, 8:50 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
70 kt

Counties Blaine County, NE, Boyd County, NE, Brown County, NE, Cherry County, NE, Garden County, NE, Garfield County, NE, Grant County, NE, Holt County, NE, Hooker County, NE, Keya Paha County, NE, Loup County, NE, Rock County, NE, Sheridan County, NE, Thomas County, NE, Wheeler County, NE

The radar

The North Platte radar (KLNX), 71 km from the middle of the area, began a volume at 23:06 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
50%
One or more gusts of 65 knots or more
30%
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
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 18, 6:10 PM CDTSevere Thunderstorm WarningLBFSheridan65 min
Jul 18, 6:25 PM CDTSevere Thunderstorm WarningLBFSheridan65 min
Jul 18, 6:50 PM CDTSevere Thunderstorm WarningLBFGarden55 min
Jul 18, 7:25 PM CDTSevere Thunderstorm WarningLBFSheridan65 min
Jul 18, 7:39 PM CDTSevere Thunderstorm WarningLBFGarden36 min
Jul 18, 8:04 PM CDTSevere Thunderstorm WarningLBFArthur, Garden, Grant, Sheridan56 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, 11.1 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 12:00Z on 2007-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 121 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 2007-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 square meters per square second.1939Sfc1 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
121 J/kg
Mixed-layer CIN
-604 J/kg
Mixed-layer LCL
2358 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
102 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 18, 1:51 PM CDTMesoscale DiscussionSPCCherry, Dawes, Keya Paha, Sheridan54 min
Jul 18, 4:15 PM CDTMesoscale DiscussionSPCBoyd, Cedar, Dixon, Knox3 hr

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.