Alert archive / Nebraska / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 88, NWS Cheyenne, WY

July 9, 2021Box Butte County, Dawes County, Sioux County, Nebraska

NWS Cheyenne, WY issued this severe thunderstorm warning at Jul 9, 2021, 4:30 PM MDT for Box Butte County, Dawes County, Sioux County, Nebraska. It was in force for 45 min. 4 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: Jul 9, 2021, 4:30 PM MDT (22:30 UTC)
Expired: Jul 9, 2021, 5:15 PM MDT
In force: 45 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Tornado: Possible
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), 189 km from the middle of the area, began a volume at 22:32 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
Jul 9, 4:42 PM MDT	HAIL 1.75	10 W Hemingford, NE
Jul 9, 4:44 PM MDT	HAIL 2	3 W Hemingford, NE
Jul 9, 5:04 PM MDT	HAIL 2.5	3 W Hemingford, NE	ESTIMATED BASED ON SEVERAL PHOTOS FROM SOCIAL MEDIA.
Jul 9, 5:10 PM MDT	HAIL 2.5	1 Wsw Marsland, NE	LOCATION AND TIMING ESTIMATED FROM RADAR.

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
Jul 9, 2:16 PM MDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 10.5 hours before the alert went out and 186 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: 766 J/kg
Mixed-layer CIN: -307 J/kg
Mixed-layer LCL: 1363 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 117 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

549 
WUUS55 KCYS 092230
SVRCYS
NEC013-045-165-092315-
/O.NEW.KCYS.SV.W.0088.210709T2230Z-210709T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Cheyenne WY
430 PM MDT Fri Jul 9 2021

The National Weather Service in Cheyenne has issued a

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

* Until 515 PM MDT.

* At 429 PM MDT, a severe thunderstorm was located 9 miles northeast
  of Flahertys Corner, or 32 miles northwest of Alliance, moving
  southeast at 25 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...
  Hemingford, Box Butte Campground, Berea, Box Butte Dam and
  Marsland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows!

&&

LAT...LON 4250 10359 4262 10343 4237 10275 4211 10309
TIME...MOT...LOC 2229Z 299DEG 23KT 4242 10332 

TORNADO...POSSIBLE
HAIL...1.75IN
WIND...60MPH
 
$$

Brothers

2 follow-up statements

372 
WWUS55 KCYS 092250
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
450 PM MDT Fri Jul 9 2021

NEC013-045-165-092315-
/O.CON.KCYS.SV.W.0088.000000T0000Z-210709T2315Z/
Box Butte NE-Dawes NE-Sioux NE-
450 PM MDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM MDT
FOR NORTHERN BOX BUTTE...SOUTHWESTERN DAWES AND EAST CENTRAL SIOUX
COUNTIES...

At 449 PM MDT, a severe thunderstorm was located near Hemingford, or 
23 miles northwest of Alliance, moving southeast at 25 mph. Trained 
spotters reported half dollar size hail west of Hemingford at 442 PM 
MDT.

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

SOURCE...Trained weather spotters.

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...
Hemingford, Box Butte Campground, Berea, Box Butte Dam and Marsland. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows.

&&

LAT...LON 4250 10359 4262 10343 4237 10275 4211 10309
TIME...MOT...LOC 2249Z 299DEG 23KT 4236 10316 

TORNADO...POSSIBLE
HAIL...1.75IN
WIND...60MPH
 
$$

Brothers

673 
WWUS55 KCYS 092257
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
457 PM MDT Fri Jul 9 2021

NEC013-045-165-092315-
/O.CON.KCYS.SV.W.0088.000000T0000Z-210709T2315Z/
Box Butte NE-Dawes NE-Sioux NE-
457 PM MDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM MDT
FOR NORTHERN BOX BUTTE...SOUTHWESTERN DAWES AND EAST CENTRAL SIOUX
COUNTIES...

At 456 PM MDT, a severe thunderstorm was located near Hemingford, or
18 miles northwest of Alliance, moving southeast at 30 mph.

HAZARD...Tennis 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...
Hemingford, Box Butte Campground, Berea, Box Butte Dam and Marsland. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows.

&&

LAT...LON 4250 10359 4262 10343 4237 10275 4211 10309
TIME...MOT...LOC 2256Z 304DEG 26KT 4229 10314 

TORNADO...POSSIBLE
HAIL...2.50IN
WIND...60MPH
 
$$

Brothers

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 2:20 PM MDT	Severe Thunderstorm Warning	CYS	Kimball	40 min
Jul 9, 2:51 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Kimball	39 min
Jul 9, 2:58 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Cheyenne, Kimball, Morrill	47 min
Jul 9, 3:32 PM MDT	Special Weather Statement	CYS	Sioux	28 min
Jul 9, 3:37 PM MDT	Severe Thunderstorm Warning	CYS	Cheyenne, Kimball	42 min
Jul 9, 3:54 PM MDT	Severe Thunderstorm Warning	CYS	Dawes, Sioux	36 min
Jul 9, 5:08 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Dawes	52 min
Jul 9, 5:42 PM MDT	Tornado Warning	CYS	Box Butte	33 min
Jul 9, 5:49 PM MDT	Areal Flood Advisory	CYS	Box Butte, Morrill	3 hr
Jul 9, 5:58 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Morrill	47 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.