Alert archive / Nebraska / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 122, NWS Cheyenne, WY

August 14, 2021Box Butte County, Dawes County, Sioux County, Nebraska

NWS Cheyenne, WY issued this severe thunderstorm warning at Aug 14, 2021, 4:50 PM MDT for Box Butte County, Dawes County, Sioux County, Nebraska. It was in force for 40 min. 5 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 14, 2021, 4:50 PM MDT (22:50 UTC)
Expired: Aug 14, 2021, 5:30 PM MDT
In force: 40 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Damage threat: Considerable
Hail: 1.75 in
Wind: 60.0 mph

Counties Box Butte County, NE, Dawes County, NE, Sioux County, NE

The radar

The Cheyenne radar (KCYS), 177 km from the middle of the area, began a volume at 22:51 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 was reported inside it

Time	Report	Where	Remark
Aug 14, 4:59 PM MDT	HAIL 1.25	3 Nw Marsland, NE
Aug 14, 5:09 PM MDT	HAIL 1.75	15 W Hemingford, NE
Aug 14, 5:14 PM MDT	TORNADO	17 Wsw Hemingford, NE	BRIEF LANDSPOUT TORNADO WAS VIEWED BY A TRAINED SPOTTER.
Aug 14, 5:18 PM MDT	HAIL 1.5	9 Ssw Marsland, NE
Aug 14, 5:35 PM MDT	HAIL 2.5	20 Wnw Alliance, NE	DELAYED REPORT. RECEIVED VIA TWITTER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 14, 3:28 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 10.8 hours before the alert went out and 211 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 911 J/kg
Mixed-layer CIN: -150 J/kg
Mixed-layer LCL: 1691 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 93 m²/s²
0-3 km storm-relative helicity: 90 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.7

Open this sounding in Storm Lab

The text

As transmitted.

412 
WUUS55 KCYS 142250
SVRCYS
NEC013-045-165-142330-
/O.NEW.KCYS.SV.W.0122.210814T2250Z-210814T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Cheyenne WY
450 PM MDT Sat Aug 14 2021

The National Weather Service in Cheyenne has issued a

* Severe Thunderstorm Warning for...
  Box Butte County in the Panhandle of Nebraska...
  Southwestern Dawes County in the Panhandle of Nebraska...
  Southeastern Sioux County in the Panhandle of Nebraska...

* Until 530 PM MDT.

* At 450 PM MDT, a severe thunderstorm was located 8 miles northeast
  of Flahertys Corner, or 33 miles southwest of Chadron, moving south
  at 30 mph.

  HAZARD...Golf ball size hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           wind damage to roofs, siding, and trees.

* Locations impacted include...
  Alliance, Hemingford, Kilpatrick Lake, Alliance Airport, Berea,
  Flahertys Corner and Marsland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in Cheyenne.

&&

LAT...LON 4201 10348 4250 10347 4256 10331 4203 10269
      4202 10270
TIME...MOT...LOC 2250Z 354DEG 26KT 4242 10336 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Claycomb

1 follow-up statement

605 
WWUS55 KCYS 142308
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
508 PM MDT Sat Aug 14 2021

NEC045-142317-
/O.CAN.KCYS.SV.W.0122.000000T0000Z-210814T2330Z/
Dawes NE-
508 PM MDT Sat Aug 14 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN DAWES COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
the Panhandle of Nebraska.

LAT...LON 4201 10348 4242 10345 4242 10315 4203 10269
      4202 10270
TIME...MOT...LOC 2307Z 352DEG 24KT 4231 10334 

$$

NEC013-165-142330-
/O.CON.KCYS.SV.W.0122.000000T0000Z-210814T2330Z/
Box Butte NE-Sioux NE-
508 PM MDT Sat Aug 14 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM MDT
FOR BOX BUTTE AND SOUTHEASTERN SIOUX COUNTIES...

At 507 PM MDT, a severe thunderstorm was located near Flahertys
Corner, or 27 miles northwest of Alliance, moving south at 30 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
Alliance, Hemingford, Kilpatrick Lake, Berea, Flahertys Corner and
Alliance Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Cheyenne.

&&

LAT...LON 4201 10348 4242 10345 4242 10315 4203 10269
      4202 10270
TIME...MOT...LOC 2307Z 352DEG 24KT 4231 10334 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Claycomb

The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 14, 3:54 PM MDT	Severe Thunderstorm Warning	CYS	Dawes	51 min
Aug 14, 4:06 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Dawes, Sioux	39 min
Aug 14, 4:14 PM MDT	Severe Thunderstorm Warning Considerable damage threat	CYS	Dawes	46 min
Aug 14, 4:45 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Dawes	45 min
Aug 14, 5:22 PM MDT	Severe Thunderstorm Warning Considerable damage threat	CYS	Box Butte, Morrill, Scotts Bluff, Sioux	38 min
Aug 14, 5:52 PM MDT	Severe Thunderstorm Warning Destructive damage threat	CYS	Box Butte, Morrill, Scotts Bluff, Sioux	38 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 2021 Every severe thunderstorm warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.