Alert archive / Nebraska / Special Weather Statements in 2021

Special Weather Statement, NWS Cheyenne, WY

August 19, 2021Box Butte County, Nebraska

NWS Cheyenne, WY issued this special weather statement at Aug 19, 2021, 4:37 PM MDT for Box Butte County, Nebraska. It was in force for 38 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 19, 2021, 4:37 PM MDT (22:37 UTC)
Expired: Aug 19, 2021, 5:15 PM MDT
In force: 38 min
Issued by: NWS Cheyenne, WY
Hail: 0.50 in
Wind: 50

County Box Butte County, NE

The radar

The Cheyenne radar (KCYS), 178 km from the middle of the area, began a volume at 22:39 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.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 10.6 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: 541 J/kg
Mixed-layer CIN: -64 J/kg
Mixed-layer LCL: 810 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 125 m²/s²
0-3 km storm-relative helicity: 96 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Cheyenne, WY wrote its last area forecast discussion before this special weather statement went out at Aug 19, 2:38 PM MDT, 1 hour 59 minutes earlier.

Area forecast discussion, Aug 19, 2:38 PM MDT, 1 hour 59 minutes before

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Hazardous weather outlook, Aug 19, 5:40 AM MDT, 10 hours 57 minutes before

Hazardous Weather Outlook
National Weather Service Cheyenne WY
540 AM MDT Thu Aug 19 2021

NEZ002-003-019>021-054-055-095-096-WYZ101>103-106>108-116>119-
201145-
Dawes County-Box Butte County-Scotts Bluff County-Banner County-
Morrill County-Kimball County-Cheyenne County-
Northern Sioux County-Southern Sioux County-
Converse County Lower Elevations-Niobrara County-
North Laramie Range-
Central Laramie Range and Southwest Platte County-
East Platte County-Goshen County-South Laramie Range-
South Laramie Range Foothills-Central Laramie County-
East Laramie County-
540 AM MDT Thu Aug 19 2021

This hazardous weather outlook is for the western Nebraska
panhandle...east central Wyoming and far southeast Wyoming along
and east of Interstate 25.

.DAY ONE...TODAY AND TONIGHT

Showers and thunderstorms will redevelop late this morning and
early this afternoon and quickly move northeast across the area as
a Pacific storm system drifts east over the area. Some of these
thunderstorms will become severe today with several rounds of
thunderstorms possible into late this evening. Severe
thunderstorms may contain strong winds, very heavy rainfall which
may result in flash flooding, and large hail. Please monitor the
latest forecasts for additional statements or severe weather watches
this afternoon.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

Much cooler temperatures are expected behind the surface cold
front Friday and Saturday.

.Spotter information statement...

Spotter activation is possible this afternoon and this evening.

WYZ104-105-109-111>115-201145-
Ferris/Seminoe/Shirley Mountains-Shirley Basin-
Central Carbon County-Southwest Carbon County-Sierra Madre Range-
Upper North Platte River Basin-Snowy Range-Laramie Valley-
540 AM MDT Thu Aug 19 2021

This hazardous weather outlook is for portions of south central
Wyoming, mainly west of Interstate 25.

.DAY ONE...TODAY AND TONIGHT

Showers and thunderstorms will continue to redevelop this morning
and quickly move northeast across the area as a Pacific storm
system drifts east over the area. Some of these thunderstorms may
become strong today with several rounds of thunderstorms possible
into late this evening.

In addition, some light snowfall is possible across the higher
peaks of the Snowy Range and Sierra Madre Range tonight and early
Friday morning as the colder air arrives behind the cold front.
Any snow accumulations should be minimal and confined to areas
above 10,000 feet.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

Much cooler temperatures are expected behind the surface cold
front Friday and Saturday. Strong gusty winds are expected Friday
morning across the wind prone areas.

.Spotter information statement...

Spotter activation is unlikely, but spotters are urged to alert
the National Weather Service of any strong winds and hail.

WYZ110-201145-
North Snowy Range Foothills-
540 AM MDT Thu Aug 19 2021

This hazardous weather outlook is for portions of south central
Wyoming.

.DAY ONE...TODAY AND TONIGHT

Showers and thunderstorms will continue to redevelop this morning
and quickly move northeast across the area as a Pacific storm
system drifts east over the area. Some of these thunderstorms may
become strong today with several rounds of thunderstorms possible
into late this evening.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

Locally strong west winds are forecast for the Arlington and Elk
Mountain areas as the storm system pushes east of the region. West
winds of 35 to 45 mph with gusts up to 65 mph are possible Friday
morning. Winds are expected to diminish slightly in the afternoon.

.Spotter information statement...

Spotter activation is unlikely, but spotters are urged to alert
the National Weather Service of any strong winds and hail.

In the hours before

Special weather statement, Aug 19, 1:35 PM MDT, 3 hours 2 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
135 PM MDT Thu Aug 19 2021

NEZ055-192000-
Cheyenne NE-
135 PM MDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of central Cheyenne
County through 200 PM MDT...

At 135 PM MDT, Doppler radar was tracking a strong thunderstorm near
Lorenzo, or 11 miles southwest of Sidney, moving north at 35 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Sidney, Gurley, Brownson, Sidney Airport and Lorenzo.

This includes Interstate 80 in Nebraska between mile markers 44 and
59.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Severe Thunderstorm Watch remains in effect until 800 PM MDT for
the Panhandle of Nebraska.

&&

LAT...LON 4140 10320 4134 10285 4100 10300 4100 10326
      4101 10326
TIME...MOT...LOC 1935Z 193DEG 32KT 4103 10314

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Hammer

Special weather statement, Aug 19, 2:06 PM MDT, 2 hours 31 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
206 PM MDT Thu Aug 19 2021

NEZ055-192030-
Cheyenne NE-
206 PM MDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of central Cheyenne
County through 230 PM MDT...

At 206 PM MDT, Doppler radar was tracking a strong thunderstorm near
Sidney Airport, or near Sidney, moving northeast at 20 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Sidney, Gurley, Colton, Brownson and Sidney Airport.

This includes Interstate 80 in Nebraska between mile markers 49 and
64.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Severe Thunderstorm Watch remains in effect until 800 PM MDT for
the Panhandle of Nebraska.

&&

LAT...LON 4101 10298 4110 10318 4139 10304 4125 10273
TIME...MOT...LOC 2006Z 210DEG 16KT 4113 10304

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Hammer

Special weather statement, Aug 19, 2:34 PM MDT, 2 hours 3 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
234 PM MDT Thu Aug 19 2021

NEZ055-192100-
Cheyenne NE-
234 PM MDT Thu Aug 19 2021

...Strong thunderstorms will impact portions of eastern Cheyenne
County through 300 PM MDT...

At 234 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Gurley to 8 miles northwest of Twin
Buttes. Movement was north at 35 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Sidney, Lodgepole, Gurley, Colton, Sunol, Brownson, Lorenzo and
Sidney Airport.

This includes Interstate 80 in Nebraska between mile markers 51 and
77.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

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

A Severe Thunderstorm Watch remains in effect until 800 PM MDT for
the Panhandle of Nebraska.

&&

LAT...LON 4100 10262 4101 10316 4107 10319 4143 10292
      4143 10264 4140 10263 4139 10261
TIME...MOT...LOC 2034Z 200DEG 29KT 4133 10293 4102 10285

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

Hammer

Special weather statement, Aug 19, 3:18 PM MDT, 1 hour 19 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
318 PM MDT Thu Aug 19 2021

NEZ021-055-192145-
Cheyenne NE-Morrill NE-
318 PM MDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of northwestern
Cheyenne and southwestern Morrill Counties through 345 PM MDT...

At 317 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles west of Gurley, or 18 miles northwest of Sidney, moving north
at 25 mph.

HAZARD...Wind gusts up to 50 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This storm will remain over mainly rural areas of northwestern
Cheyenne and southwestern Morrill Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Severe Thunderstorm Watch remains in effect until 800 PM MDT for
the Panhandle of Nebraska.

&&

LAT...LON 4129 10308 4129 10322 4159 10329 4159 10295
TIME...MOT...LOC 2117Z 182DEG 24KT 4137 10316

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

Brothers

Special weather statement, Aug 19, 4:37 PM MDT, 0 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
437 PM MDT Thu Aug 19 2021

NEZ003-021-192315-
Box Butte NE-Morrill NE-
437 PM MDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of southeastern Box
Butte and north central Morrill Counties through 515 PM MDT...

At 436 PM MDT, Doppler radar was tracking a strong thunderstorm near
Angora, or 16 miles southwest of Alliance, moving north at 30 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Alliance.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Severe Thunderstorm Watch remains in effect until 800 PM MDT for
the Panhandle of Nebraska.

&&

LAT...LON 4180 10289 4181 10307 4220 10314 4218 10277
TIME...MOT...LOC 2236Z 186DEG 26KT 4188 10301

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

Brothers

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 18, 6:34 PM MDT	Special Weather Statement	CYS	Laramie	26 min
Aug 18, 7:41 PM MDT	Special Weather Statement	CYS	Goshen	34 min
Aug 18, 9:49 PM MDT	Special Weather Statement	CYS	Goshen	41 min
Aug 19, 2:10 AM MDT	High Wind Warning	CYS	Albany, Carbon, Laramie	34 hr
Aug 19, 10:00 AM MDT	Special Weather Statement	CYS	Converse	45 min
Aug 18, 6:46 PM MDT	Special Weather Statement	CYS	Dawes	29 min
Aug 18, 7:06 PM MDT	Areal Flood Advisory	CYS	Dawes	4 hr
Aug 18, 7:10 PM MDT	Special Weather Statement	CYS	Scotts Bluff	35 min
Aug 18, 7:16 PM MDT	Special Weather Statement	CYS	Sioux	29 min
Aug 18, 9:17 PM MDT	Special Weather Statement	CYS	Sioux	43 min
Aug 19, 1:35 PM MDT	Special Weather Statement	CYS	Cheyenne	25 min
Aug 19, 2:06 PM MDT	Special Weather Statement	CYS	Cheyenne	24 min
Aug 19, 2:34 PM MDT	Special Weather Statement	CYS	Cheyenne	26 min
Aug 19, 3:18 PM MDT	Special Weather Statement	CYS	Cheyenne	27 min
Aug 19, 4:28 PM MDT	Areal Flood Advisory	CYS	Cheyenne	2 hr

Nearby

Special Weather Statements in Nebraska, 2021 Every special weather statement 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.