Alert archive / Nebraska / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 137, NWS Cheyenne, WY

September 1, 2021Box Butte County, Morrill County, Nebraska

NWS Cheyenne, WY issued this severe thunderstorm warning at Sep 1, 2021, 5:49 PM MDT for Box Butte County, Morrill County, Nebraska. It was in force for 41 min. 2 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: Sep 1, 2021, 5:49 PM MDT (23:49 UTC)
Expired: Sep 1, 2021, 6:30 PM MDT
In force: 41 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Box Butte County, NE, Morrill County, NE

The radar

The Cheyenne radar (KCYS), 177 km from the middle of the area, began a volume at 23:50 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
Sep 1, 6:18 PM MDT	TSTM WND GST 66	5 Se Alliance, NE	CORRECTS PREVIOUS TSTM WND GST REPORT FROM 5 SE ALLIANCE. ASOS STATION KAIA ALLIANCE AIRPORT.
Sep 1, 6:25 PM MDT	TSTM WND GST 66	5 Se Alliance, NE	ASOS STATION KAIA ALLIANCE AIRPORT.

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
Sep 1, 5:26 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 11.8 hours before the alert went out and 216 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: 19 J/kg
Mixed-layer CIN: -769 J/kg
Mixed-layer LCL: 775 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 241 m²/s²
0-3 km storm-relative helicity: 221 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

650 
WUUS55 KCYS 012349
SVRCYS
NEC013-123-020030-
/O.NEW.KCYS.SV.W.0137.210901T2349Z-210902T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Cheyenne WY
549 PM MDT Wed Sep 1 2021

The National Weather Service in Cheyenne has issued a

* Severe Thunderstorm Warning for...
  Southeastern Box Butte County in the Panhandle of Nebraska...
  North central Morrill County in the Panhandle of Nebraska...

* Until 630 PM MDT.

* At 549 PM MDT, a severe thunderstorm was located near Angora, or 14
  miles southwest of Alliance, moving northeast at 20 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Alliance and Alliance Airport. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4180 10296 4191 10315 4220 10303 4201 10269
TIME...MOT...LOC 2349Z 218DEG 17KT 4192 10300 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Mokry

3 follow-up statements

868 
WWUS55 KCYS 020001
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
601 PM MDT Wed Sep 1 2021

NEC013-123-020030-
/O.CON.KCYS.SV.W.0137.000000T0000Z-210902T0030Z/
Box Butte NE-Morrill NE-
601 PM MDT Wed Sep 1 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM MDT
FOR SOUTHEASTERN BOX BUTTE AND NORTH CENTRAL MORRILL COUNTIES...

At 601 PM MDT, a severe thunderstorm was located 9 miles southwest of
Alliance Airport, or 10 miles southwest of Alliance, moving northeast
at 20 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Alliance and Alliance Airport. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4183 10292 4190 10302 4199 10312 4220 10303
      4201 10269
TIME...MOT...LOC 0001Z 218DEG 17KT 4197 10295 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Mokry

751 
WWUS55 KCYS 020005
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
605 PM MDT Wed Sep 1 2021

NEC013-123-020030-
/O.CON.KCYS.SV.W.0137.000000T0000Z-210902T0030Z/
Box Butte NE-Morrill NE-
605 PM MDT Wed Sep 1 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM MDT
FOR SOUTHEASTERN BOX BUTTE AND NORTH CENTRAL MORRILL COUNTIES...

At 605 PM MDT, a severe thunderstorm was located 8 miles southwest of
Alliance Airport, or 10 miles south of Alliance, moving northeast at
20 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 and Alliance Airport. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4183 10292 4190 10302 4199 10312 4220 10303
      4201 10269
TIME...MOT...LOC 0005Z 232DEG 17KT 4196 10291 

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

$$

Mokry

638 
WWUS55 KCYS 020026
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
626 PM MDT Wed Sep 1 2021

NEC013-123-020034-
/O.EXP.KCYS.SV.W.0137.000000T0000Z-210902T0030Z/
Box Butte NE-Morrill NE-
626 PM MDT Wed Sep 1 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BOX BUTTE AND
NORTH CENTRAL MORRILL COUNTIES WILL EXPIRE AT 630 PM MDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

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

LAT...LON 4183 10292 4190 10302 4199 10312 4220 10303
      4201 10269
TIME...MOT...LOC 0024Z 218DEG 17KT 4203 10284 

$$

Mokry

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 1, 4:38 PM MDT	Special Weather Statement	CYS	Morrill	37 min
Sep 1, 4:49 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Morrill, Scotts Bluff	41 min
Sep 1, 5:06 PM MDT	Severe Thunderstorm Warning Destructive damage threat	CYS	Morrill	39 min
Sep 1, 5:45 PM MDT	Special Weather Statement	CYS	Box Butte	30 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.