Alert archive / Nebraska / Severe Thunderstorm Watches in 2017

Severe Thunderstorm Watch 493

October 2, 201729 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at Oct 2, 2017, 8:00 PM CDT for 29 counties in Nebraska. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Oct 2, 2017, 8:00 PM CDT (01:00 UTC)
Expired
Oct 3, 2017, 12:00 AM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 29 counties

Adams County, NE, Boone County, NE, Buffalo County, NE, Butler County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Fillmore County, NE, Franklin County, NE, Furnas County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Howard County, NE, Kearney County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nuckolls County, NE, Phelps County, NE, Platte County, NE, Polk County, NE, Seward County, NE, Stanton County, NE, Thayer County, NE, Wayne County, NE, Webster County, NE, York County, NE

The radar

The Omaha radar (KOAX), 104 km from the middle of the area, began a volume at 01:00 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
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Oct 2, 8:00 PM CDTSevere Thunderstorm WarningGIDHall, Hamilton, Merrick, Polk20 min
Oct 2, 8:11 PM CDTSevere Thunderstorm WarningGIDMerrick, Nance34 min
Oct 2, 8:16 PM CDTSevere Thunderstorm WarningGIDFranklin, Webster44 min
Oct 2, 8:24 PM CDTSevere Thunderstorm WarningGIDAdams, Clay, Hall, Hamilton36 min
Oct 2, 8:51 PM CDTSevere Thunderstorm WarningGIDHamilton24 min
Oct 2, 8:55 PM CDTSevere Thunderstorm WarningGIDAdams, Webster35 min
Oct 2, 9:54 PM CDTSevere Thunderstorm WarningGIDBuffalo, Dawson27 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, 1.0 hours before the alert went out and 103 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 2017-10-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 778 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, Omaha, NE at 00:00Z on 2017-10-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 307 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
778 J/kg
Mixed-layer CIN
-59 J/kg
Mixed-layer LCL
1536 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
307 m²/s²
0-3 km storm-relative helicity
383 m²/s²
Significant tornado parameter
0.7
Supercell composite
3.8

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 2, 8:18 PM CDTMesoscale DiscussionSPCBlaine, Chase, Custer, Dundy, Frontier, Hayes and 8 more2 hr

Nearby

Severe Thunderstorm Watches in Nebraska, 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.