Alert archive / Nebraska / Special Weather Statements in 2021

Special Weather Statement, NWS Cheyenne, WY

May 21, 2021Box Butte County, Nebraska

NWS Cheyenne, WY issued this special weather statement at May 21, 2021, 4:28 PM MDT for Box Butte County, Nebraska. It was in force for 47 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: May 21, 2021, 4:28 PM MDT (22:28 UTC)
Expired: May 21, 2021, 5:15 PM MDT
In force: 47 min
Issued by: NWS Cheyenne, WY

County Box Butte County, NE

The radar

The Cheyenne radar (KCYS), 170 km from the middle of the area, began a volume at 22:31 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

Rapid City, SD (KUNR), launched 12:00Z, 10.5 hours before the alert went out and 217 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1093 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 112 m²/s²
0-3 km storm-relative helicity: 324 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 May 21, 2:50 PM MDT, 1 hour 38 minutes earlier.

Area forecast discussion, May 21, 2:50 PM MDT, 1 hour 38 minutes before

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Hazardous weather outlook, May 21, 5:40 AM MDT, 10 hours 48 minutes before

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In the hours before

Special weather statement, May 21, 4:10 PM MDT, 18 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
410 PM MDT Fri May 21 2021

NEZ002-003-212300-
Box Butte NE-Dawes NE-
410 PM MDT Fri May 21 2021

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN BOX BUTTE AND
SOUTHWESTERN DAWES COUNTIES UNTIL 500 PM MDT...

At 409 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Kilpatrick Lake, or 19 miles northwest of Alliance,
moving north at 55 mph.

Nickel size hail and wind gusts of 50 to 55 mph will be possible with
this storm.

This strong thunderstorm will be near...
  Box Butte Campground around 425 PM MDT.
  Whitney Lake around 450 PM MDT.

Other locations impacted by this storm include Marsland and Whitney.

LAT...LON 4210 10316 4210 10330 4279 10347 4279 10303
TIME...MOT...LOC 2209Z 179DEG 50KT 4222 10323

Rubin

Special weather statement, May 21, 4:28 PM MDT, 0 minutes before

Special Weather Statement
National Weather Service Cheyenne WY
428 PM MDT Fri May 21 2021

NEZ003-021-212315-
Box Butte NE-Morrill NE-
428 PM MDT Fri May 21 2021

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN BOX BUTTE AND
NORTHWESTERN MORRILL COUNTIES UNTIL 515 PM MDT...

At 427 PM MDT, Doppler radar was tracking a strong thunderstorm near
Kilpatrick Lake, or 21 miles west of Alliance, moving north at 40
mph.

Penny size hail and wind gusts of 50 to 55 mph will be possible with
this storm.

This strong thunderstorm will be near...
  Kilpatrick Lake around 435 PM MDT.
  Hemingford around 500 PM MDT.

A Severe Thunderstorm Watch remains in effect until 1000 PM MDT for
the Panhandle of Nebraska.

LAT...LON 4193 10322 4196 10335 4242 10338 4242 10298
TIME...MOT...LOC 2227Z 186DEG 35KT 4200 10327

Rubin

The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 7:07 PM MDT	Severe Thunderstorm Warning	CYS	Goshen	38 min
May 20, 7:27 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Niobrara, Platte	35 min
May 20, 6:10 PM MDT	Special Weather Statement	CYS	Banner	50 min
May 20, 6:49 PM MDT	Special Weather Statement	CYS	Scotts Bluff	41 min
May 20, 6:54 PM MDT	Special Weather Statement	CYS	Kimball	51 min
May 20, 7:15 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Cheyenne, Kimball	45 min
May 20, 7:55 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Cheyenne, Kimball, Morrill	39 min
May 20, 8:36 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Cheyenne, Kimball	24 min
May 21, 4:10 PM MDT	Special Weather Statement	CYS	Dawes	50 min
May 21, 4:38 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Dawes	52 min
May 21, 5:26 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Morrill, Scotts Bluff, Sioux	49 min
May 21, 5:32 PM MDT	Severe Thunderstorm Warning	CYS	Dawes	43 min

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.