Alert archive / Nebraska / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 257
The Storm Prediction Center issued this severe thunderstorm watch at Jun 11, 2021, 5:36 AM CDT for 28 counties in Nebraska. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 11, 2021, 5:36 AM CDT (10:36 UTC)
- Expired
- Jun 11, 2021, 11:00 AM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 28 counties
Antelope County, NE, Boone County, NE, Burt County, NE, Butler County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Greeley County, NE, Knox County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, York County, NE
The radar
The Omaha radar (KOAX), 131 km from the middle of the area, began a volume at 10:39 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
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 50%
Warnings issued inside it
10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 11, 5:55 AM CDT | Severe Thunderstorm Warning | OAX | Antelope, Cedar, Knox, Pierce, Wayne | 35 min |
| Jun 11, 6:45 AM CDT | Severe Thunderstorm Warning | OAX | Boone | 30 min |
| Jun 11, 7:10 AM CDT | Severe Thunderstorm Warning | OAX | Burt, Cuming, Madison, Platte, Stanton, Thurston | 35 min |
| Jun 11, 7:24 AM CDT | Severe Thunderstorm Warning | OAX | Platte | 36 min |
| Jun 11, 7:31 AM CDT | Severe Thunderstorm Warning | GID | Merrick, Nance, Polk | 29 min |
| Jun 11, 7:34 AM CDT | Severe Thunderstorm Warning | OAX | Burt, Cuming, Dodge, Thurston | 26 min |
| Jun 11, 7:41 AM CDT | Severe Thunderstorm Warning | OAX | Butler, Colfax, Madison, Platte, Stanton | 34 min |
| Jun 11, 7:50 AM CDT | Severe Thunderstorm Warning | OAX | Burt, Washington | 40 min |
| Jun 11, 8:13 AM CDT | Severe Thunderstorm Warning | OAX | Butler, Colfax, Platte | 47 min |
| Jun 11, 9:00 AM CDT | Severe Thunderstorm Warning | OAX | Butler, Lancaster, Saunders, Seward | 30 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, 10.6 hours before the alert went out and 131 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.
- Mixed-layer CAPE
- 1135 J/kg
- Mixed-layer CIN
- -96 J/kg
- Mixed-layer LCL
- 2153 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- -6 m²/s²
- 0-3 km storm-relative helicity
- 85 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.6
The text
As transmitted.
323 WWUS20 KWNS 111033 SEL7 SPC WW 111033 NEZ000-111600- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 257 NWS Storm Prediction Center Norman OK 535 AM CDT Fri Jun 11 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northeast Nebraska * Effective this Friday morning from 535 AM until 1100 AM CDT. * Primary threats include... Isolated damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...A line of storms is expected to develop southeastward across northeast Nebraska through mid morning, with an accompanying threat for isolated damaging winds and large hail. The severe thunderstorm watch area is approximately along and 50 statute miles east and west of a line from 10 miles west northwest of Yankton SD to 45 miles south southeast of Norfolk NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 255...WW 256... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 31025. ...Thompson
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 10, 8:28 PM CDT | Mesoscale Discussion | SPC | Arthur, Banner, Blaine, Box Butte, Brown, Cherry and 12 more | 92 min |
| Jun 10, 9:08 PM CDT | Severe Thunderstorm Watch | SPC | Arthur, Banner, Blaine, Box Butte, Brown, Cherry and 12 more | 6 hr |
| Jun 10, 11:07 PM CDT | Mesoscale Discussion | SPC | Box Butte, Dawes, Sheridan, Sioux | 83 min |
| Jun 11, 12:52 AM CDT | Mesoscale Discussion | SPC | Antelope, Boyd, Cedar, Holt, Keya Paha, Knox and 4 more | 53 min |
| Jun 11, 2:15 AM CDT | Severe Thunderstorm Watch | SPC | Dakota, Dixon | 5 hr |
| Jun 11, 7:28 AM CDT | Mesoscale Discussion | SPC | Boone, Burt, Butler, Cass, Colfax, Cuming and 18 more | 92 min |
| Jun 11, 8:30 AM CDT | Severe Thunderstorm Watch | SPC | Cass, Gage, Jefferson, Johnson, Nemaha, Otoe and 2 more | 7 hr |
| Jun 11, 10:28 AM CDT | Mesoscale Discussion | SPC | Gage, Johnson, Nemaha, Otoe, Pawnee, Richardson | 2 hr |
| Jun 10, 11:50 PM CDT | Mesoscale Discussion | SPC | Dewey, Haakon, Jackson, Jones, Meade, Mellette and 5 more | 85 min |
| Jun 11, 4:37 AM CDT | Mesoscale Discussion | SPC | Aurora, Beadle, Brookings, Brown, Charles Mix, Clark and 21 more | 83 min |
Nearby
Severe Thunderstorm Watches in Nebraska, 2021Every severe thunderstorm watch in 2021
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.