Alert archive / Nebraska / Severe Thunderstorm Watches in 2017

Severe Thunderstorm Watch 422

July 19, 20174 counties in Iowa; 14 counties in Nebraska; 10 counties in South Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Jul 19, 2017, 4:52 PM CDT for 4 counties in Iowa; 14 counties in Nebraska; 10 counties in South Dakota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jul 19, 2017, 4:52 PM CDT (21:52 UTC)
Expired
Jul 19, 2017, 10:58 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt
All 28 counties

Lyon County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Antelope County, NE, Boyd County, NE, Brown County, NE, Cedar County, NE, Cherry County, NE, Dakota County, NE, Dixon County, NE, Holt County, NE, Keya Paha County, NE, Knox County, NE, Pierce County, NE, Rock County, NE, Thurston County, NE, Wayne County, NE, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Douglas County, SD, Gregory County, SD, Hutchinson County, SD, Lincoln County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 172 km from the middle of the area, began a volume at 21:55 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
2%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
20%
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
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 19, 5:00 PM CDTSevere Thunderstorm WarningLBFBoyd, Holt45 min
Jul 19, 5:52 PM CDTSevere Thunderstorm WarningLBFHolt38 min
Jul 19, 6:30 PM CDTSevere Thunderstorm WarningLBFHolt60 min
Jul 19, 7:14 PM CDTSevere Thunderstorm WarningLBFHolt46 min
Jul 19, 7:59 PM CDTSevere Thunderstorm WarningLBFHolt46 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

Aberdeen, SD (KABR), launched 12:00Z, 9.9 hours before the alert went out and 221 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, Aberdeen, SD at 12:00Z on 2017-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Aberdeen, SD at 12:00Z on 2017-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 square meters per square second.1939587897117Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1451 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
208 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 19, 12:11 PM CDTMesoscale DiscussionSPCBremer, Buena Vista, Butler, Cerro Gordo, Cherokee, Chickasaw and 20 more2 hr
Jul 19, 12:36 PM CDTSevere Thunderstorm WatchSPCBremer, Butler, Cerro Gordo, Clay, Dickinson, Emmet and 7 more5 hr
Jul 19, 2:38 PM CDTMesoscale DiscussionSPCAllamakee, Chickasaw, Howard, Winneshiek2 hr
Jul 19, 3:29 PM CDTSevere Thunderstorm WatchSPCAllamakee, Chickasaw, Clayton, Fayette, Floyd, Howard and 2 more6 hr
Jul 19, 5:11 PM CDTMesoscale DiscussionSPCBuchanan, Clayton, Clinton, Delaware, Dubuque, Jackson and 1 more34 min
Jul 19, 5:45 PM CDTSevere Thunderstorm WatchSPCBuchanan, Cedar, Clinton, Delaware, Dubuque, Jackson and 3 more6 hr
Jul 19, 6:32 PM CDTMesoscale DiscussionSPCAllamakee, Chickasaw, Clayton, Fayette, Floyd, Howard and 2 more58 min
Jul 18, 7:58 PM CDTMesoscale DiscussionSPCBox Butte, Dawes, Sheridan, Sioux2 hr
Jul 19, 2:52 PM CDTMesoscale DiscussionSPCBoyd83 min
Jul 19, 7:01 AM CDTMesoscale DiscussionSPCBrown, Campbell, Corson, Day, Dewey, Edmunds and 13 more119 min
Jul 19, 9:55 AM CDTMesoscale DiscussionSPCBeadle, Brookings, Clark, Codington, Day, Deuel and 6 more2 hr
Jul 19, 10:24 AM CDTSevere Thunderstorm WatchSPCAurora, Beadle, Brookings, Clark, Codington, Davison and 15 more4 hr

Nearby

Severe Thunderstorm Watches in Nebraska, 2017Severe Thunderstorm Watches in South Dakota, 2017Severe Thunderstorm Watches in Iowa, 2017Every severe thunderstorm watch in 2017

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.