Alert archive / Nebraska / Tornado Watches in 2010

Tornado Watch 85

April 23, 20109 counties in Iowa; 31 counties in Nebraska

The Storm Prediction Center issued this tornado watch at Apr 23, 2010, 7:28 PM CDT for 9 counties in Iowa; 31 counties in Nebraska. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 23, 2010, 7:28 PM CDT (00:28 UTC)
Expired
Apr 24, 2010, 12:00 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 40 counties

Fremont County, IA, Harrison County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Shelby County, IA, Woodbury County, IA, Antelope County, NE, Boone County, NE, Boyd County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Gage County, NE, Holt County, NE, Johnson County, NE, Keya Paha County, NE, Knox County, NE, Lancaster County, NE, Madison County, NE, Nemaha County, NE, Otoe County, NE, Pierce County, NE, Platte County, NE, Rock County, NE, Sarpy County, NE, Saunders County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE

The radar

The Omaha radar (KOAX), 165 km from the middle of the area, began a volume at 00:31 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 23, 7:37 PM CDTSevere Thunderstorm WarningOAXLancaster38 min
Apr 23, 8:16 PM CDTTornado WarningOAXLancaster15 min
Apr 23, 8:23 PM CDTSevere Thunderstorm WarningOAXLancaster52 min
Apr 23, 8:24 PM CDTSevere Thunderstorm WarningOAXDodge, Saunders36 min
Apr 23, 8:34 PM CDTSevere Thunderstorm WarningOAXCass26 min
Apr 23, 8:53 PM CDTSevere Thunderstorm WarningOAXCass, Dodge, Douglas, Sarpy, Saunders37 min
Apr 23, 9:03 PM CDTSevere Thunderstorm WarningOAXDodge, Saunders27 min
Apr 23, 9:15 PM CDTSevere Thunderstorm WarningOAXCuming, Wayne20 min
Apr 23, 9:31 PM CDTSevere Thunderstorm WarningOAXBurt, Dodge, Douglas, Washington29 min
Apr 23, 9:48 PM CDTSevere Thunderstorm WarningOAXCass, Otoe, Saunders27 min
Apr 23, 9:53 PM CDTSevere Thunderstorm WarningOAXCedar, Knox, Pierce, Wayne37 min
Apr 23, 10:31 PM CDTSevere Thunderstorm WarningOAXBurt, Thurston, Washington29 min
Apr 23, 10:39 PM CDTSevere Thunderstorm WarningOAXFremont, Mills, Montgomery, Page36 min
Apr 23, 11:43 PM CDTSevere Thunderstorm WarningOAXHarrison, Monona14 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

Omaha, NE (KOAX), launched 00:00Z, 0.5 hours before the alert went out and 164 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, Omaha, NE at 00:00Z on 2010-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1792 joules per kilogram.LCLEL10008507005003002001001 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, Omaha, NE at 00:00Z on 2010-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 71 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
1792 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
927 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
71 m²/s²
0-3 km storm-relative helicity
164 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.9

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 23, 7:02 PM CDTMesoscale DiscussionSPCFremont, Harrison, Mills, Monona, Pottawattamie88 min
Apr 23, 9:22 PM CDTMesoscale DiscussionSPCFremont, Harrison, Mills, Monona, Pottawattamie53 min
Apr 23, 10:58 PM CDTTornado WatchSPCAdair, Adams, Audubon, Carroll, Cass, Crawford and 13 more5 hr
Apr 24, 3:15 AM CDTMesoscale DiscussionSPCDecatur, Union30 min
Apr 24, 1:29 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Buena Vista, Calhoun, Carroll and 30 more91 min
Apr 23, 10:03 PM CDTMesoscale DiscussionSPCPawnee, Richardson27 min

Nearby

Tornado Watches in Nebraska, 2010Tornado Watches in Iowa, 2010Every tornado watch in 2010

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.