Alert archive / Wyoming / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 73, NWS Cheyenne, WY

June 20, 2023Converse County, Niobrara County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jun 20, 2023, 10:06 PM MDT for Converse County, Niobrara County, Wyoming. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jun 20, 2023, 10:06 PM MDT (04:06 UTC)
Expired
Jun 20, 2023, 10:45 PM MDT
In force
39 min
Issued by
NWS Cheyenne, WY
Area
Storm-based polygon
Hail
1.5 in
Wind
60.0 mph

Counties Converse County, WY, Niobrara County, WY

The radar

The Cheyenne radar (KCYS), 208 km from the middle of the area, began a volume at 04:09 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 00:00Z, 4.1 hours before the alert went out and 419 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-pSkew-T log-p diagram, N. Platte/Lee Bi, NE at 00:00Z on 2023-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2113 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, N. Platte/Lee Bi, NE at 00:00Z on 2023-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
2113 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
1242 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning 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 severe thunderstorm warning went out at Jun 20, 8:56 PM MDT, 1 hour 10 minutes earlier.

Area forecast discussion, Jun 20, 8:56 PM MDT, 1 hour 10 minutes before
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Hazardous weather outlook, Jun 20, 3:04 PM MDT, 7 hours 2 minutes before
Hazardous Weather Outlook
National Weather Service Cheyenne WY
304 PM MDT Tue Jun 20 2023

WYZ101>103-106>108-116>119-212115-
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-
304 PM MDT Tue Jun 20 2023

This hazardous weather outlook is for portions of east central
Wyoming and southeast Wyoming.

.DAY ONE...THIS AFTERNOON AND TONIGHT

Widely scattered late afternoon and early evening thunderstorms
will develop over east central Wyoming. A few strong storms
producing small hail and gusty winds are possible.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Strong to severe thunderstorms possible Wednesday afternoon with
large hail and damaging winds possible. Daily chances for afternoon
and evening showers and thunderstorms will continue through Friday.

.Spotter information statement...

Spotter activation will not be required.

NEZ002-003-019>021-054-055-095-096-212115-
Dawes County-Box Butte County-Scotts Bluff County-Banner County-
Morrill County-Kimball County-Cheyenne County-
Northern Sioux County-Southern Sioux County-
304 PM MDT Tue Jun 20 2023

This hazardous weather outlook is for western portions of the
Nebraska Panhandle.

.DAY ONE...THIS AFTERNOON AND TONIGHT

Widely scattered thunderstorms will develop late this afternoon
and early evening. Isolated severe thunderstorms producing large
hail and damaging winds are possible.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Strong to severe thunderstorms possible Wednesday afternoon with
large hail and damaging winds possible. Daily chances for afternoon
and evening showers and thunderstorms will continue through Friday.

.Spotter information statement...

Spotter activation may be required late this afternoon and early
evening.

WYZ104-105-109>115-212115-
Ferris/Seminoe/Shirley Mountains-Shirley Basin-
Central Carbon County-North Snowy Range Foothills-
Southwest Carbon County-Sierra Madre Range-
Upper North Platte River Basin-Snowy Range-Laramie Valley-
304 PM MDT Tue Jun 20 2023

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

The probability for widespread hazardous weather is low.

.Spotter information statement...

Spotter activation will not be required.

MAJ

In the hours before

Special weather statement, Jun 20, 6:30 PM MDT, 3 hours 36 minutes before
Special Weather Statement
National Weather Service Cheyenne WY
630 PM MDT Tue Jun 20 2023

NEZ002-095-096-210115-
Dawes NE-North Sioux NE-South Sioux NE-
630 PM MDT Tue Jun 20 2023

...A strong thunderstorm will impact portions of southwestern Dawes
and east central Sioux Counties through 715 PM MDT...

At 630 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles northeast of Agate Bed National Monument, or 38 miles northeast
of Torrington, moving north-northeast at 20 mph.

HAZARD...Winds in excess of 30 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.

Locations impacted include...
Fort Robinson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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

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

&&

LAT...LON 4235 10352 4239 10375 4269 10379 4267 10339
TIME...MOT...LOC 0030Z 198DEG 17KT 4250 10371

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...30 MPH

Wills
Special weather statement, Jun 20, 6:39 PM MDT, 3 hours 27 minutes before
Special Weather Statement
National Weather Service Cheyenne WY
639 PM MDT Tue Jun 20 2023

WYZ101-210215-
Converse County Lower Elevations WY-
639 PM MDT Tue Jun 20 2023

...A strong thunderstorm will impact portions of northwestern
Converse County through 815 PM MDT...

At 639 PM MDT, Doppler radar was tracking a strong thunderstorm near
Antelope Hills, or 13 miles north of Casper, moving northeast at 30
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.

This storm will remain over mainly rural areas of northwestern
Converse County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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

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.

&&

LAT...LON 4301 10573 4299 10607 4350 10607 4350 10522
TIME...MOT...LOC 0039Z 246DEG 25KT 4302 10623

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

Wills
Local storm report, Jun 20, 7:32 PM MDT, 2 hours 34 minutes before
Preliminary Local Storm Report
National Weather Service Cheyenne WY
732 PM MDT Tue Jun 20 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0650 PM     Hail             10.5 SE Harrison        42.58N 103.74W
06/20/2023  M1.75 inch       Sioux              NE   Trained Spotter

&&
Special weather statement, Jun 20, 7:51 PM MDT, 2 hours 15 minutes before
Special Weather Statement
National Weather Service Cheyenne WY
751 PM MDT Tue Jun 20 2023

NEZ002-095-210245-
Dawes NE-North Sioux NE-
751 PM MDT Tue Jun 20 2023

...A strong thunderstorm will impact portions of northwestern Dawes
and northeastern Sioux Counties through 845 PM MDT...

At 751 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles southeast of Montrose, or 30 miles west of Chadron, moving
north at 15 mph.

HAZARD...Winds in excess of 30 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.

This storm will remain over mainly rural areas of northwestern Dawes
and northeastern Sioux Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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

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.

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 1000 PM MDT for
the Panhandle of Nebraska.

&&

LAT...LON 4276 10352 4280 10366 4300 10362 4300 10325
TIME...MOT...LOC 0151Z 196DEG 12KT 4281 10361

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...30 MPH

Wills
Special weather statement, Jun 20, 7:55 PM MDT, 2 hours 11 minutes before
Special Weather Statement
National Weather Service Cheyenne WY
755 PM MDT Tue Jun 20 2023

WYZ101-102-210300-
Converse County Lower Elevations WY-Niobrara County WY-
755 PM MDT Tue Jun 20 2023

...A strong thunderstorm will impact portions of northwestern
Niobrara and northeastern Converse Counties through 900 PM MDT...

At 755 PM MDT, Doppler radar was tracking a strong thunderstorm 15
miles west of Bill, or 33 miles north of Douglas, moving northeast at
20 mph.

HAZARD...Winds in excess of 40 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...
Bill and Dull Center.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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

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.

&&

LAT...LON 4329 10469 4320 10529 4320 10568 4350 10568
      4350 10441
TIME...MOT...LOC 0155Z 246DEG 18KT 4323 10557

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

Wills
Local storm report, Jun 20, 8:29 PM MDT, 1 hour 37 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jun 20, 6:39 PM MDTSpecial Weather StatementCYSConverse96 min
Jun 20, 7:55 PM MDTSpecial Weather StatementCYS65 min
Jun 20, 8:04 PM MDTSevere Thunderstorm WarningCYSConverse41 min
Jun 20, 11:13 PM MDTSevere Thunderstorm WarningCYSConverse, Goshen, Niobrara, Platte47 min
Jun 20, 11:52 PM MDTSevere Thunderstorm Warning Considerable damage threatCYSGoshen, Niobrara, Platte38 min
Jun 21, 2:02 PM MDTSevere Thunderstorm WarningCYSAlbany, Carbon43 min
Jun 21, 2:11 PM MDTSevere Thunderstorm Warning Considerable damage threatCYSLaramie49 min
Jun 21, 2:23 PM MDTSpecial Weather StatementCYS37 min
Jun 21, 2:40 PM MDTSevere Thunderstorm WarningCYSCarbon35 min
Jun 21, 2:45 PM MDTSevere Thunderstorm WarningCYSAlbany45 min
Jun 21, 2:54 PM MDTSevere Thunderstorm WarningCYSLaramie51 min
Jun 21, 2:59 PM MDTTornado WarningCYSAlbany31 min
Jun 21, 3:29 PM MDTTornado WarningCYSAlbany15 min
Jun 21, 3:39 PM MDTSevere Thunderstorm WarningCYSLaramie51 min
Jun 21, 3:46 PM MDTSpecial Weather StatementCYSPlatte44 min
Jun 21, 4:14 PM MDTSevere Thunderstorm Warning Considerable damage threatCYSAlbany, Platte46 min
Jun 21, 4:39 PM MDTSevere Thunderstorm WarningCYSGoshen51 min
Jun 21, 4:54 PM MDTFlash Flood WarningCYSLaramie3 hr
Jun 21, 5:00 PM MDTSpecial Weather StatementCYSPlatte45 min
Jun 21, 5:10 PM MDTSevere Thunderstorm WarningCYSGoshen, Niobrara50 min
Jun 21, 5:17 PM MDTSevere Thunderstorm WarningCYSAlbany, Platte43 min
Jun 21, 5:27 PM MDTSevere Thunderstorm Warning Considerable damage threatCYSGoshen, Niobrara28 min
Jun 21, 5:29 PM MDTSevere Thunderstorm WarningCYSLaramie, Platte19 min
Jun 21, 5:36 PM MDTSevere Thunderstorm WarningCYSPlatte39 min
Jun 21, 5:41 PM MDTSpecial Weather StatementCYSNiobrara34 min
Jun 21, 5:52 PM MDTSevere Thunderstorm WarningCYSGoshen, Niobrara20 min
Jun 20, 6:30 PM MDTSpecial Weather StatementCYSSioux45 min
Jun 20, 6:37 PM MDTSevere Thunderstorm WarningCYSSioux38 min
Jun 20, 7:05 PM MDTSevere Thunderstorm WarningCYSSioux16 min
Jun 20, 7:15 PM MDTSevere Thunderstorm WarningCYSSioux45 min
Jun 20, 7:51 PM MDTSpecial Weather StatementCYSDawes54 min
Jun 21, 1:29 AM MDTSpecial Weather StatementCYSSioux46 min
Jun 21, 12:49 PM MDTSevere Thunderstorm WarningCYSCheyenne41 min
Jun 21, 1:08 PM MDTSevere Thunderstorm WarningCYSCheyenne52 min
Jun 21, 1:11 PM MDTSevere Thunderstorm Warning Considerable damage threatCYSCheyenne49 min
Jun 21, 1:24 PM MDTTornado WarningCYSCheyenne36 min
Jun 21, 2:00 PM MDTSevere Thunderstorm WarningCYSCheyenne30 min
Jun 21, 2:22 PM MDTSpecial Weather StatementCYSMorrill23 min
Jun 21, 2:27 PM MDTSpecial Weather StatementCYSKimball33 min
Jun 21, 2:48 PM MDTSevere Thunderstorm WarningCYSKimball42 min
Jun 21, 3:09 PM MDTSevere Thunderstorm WarningCYSBanner, Scotts Bluff51 min
Jun 21, 3:19 PM MDTSpecial Weather StatementCYSBanner41 min
Jun 21, 3:57 PM MDTSpecial Weather StatementCYSScotts Bluff33 min
Jun 21, 4:22 PM MDTSpecial Weather StatementCYSSioux23 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2023Every severe thunderstorm warning in 2023

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.