Alert archive / Wyoming / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 144, NWS Cheyenne, WY

July 3, 2015Converse County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jul 3, 2015, 7:38 PM MDT for Converse County, Wyoming. It was in force for 32 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
Jul 3, 2015, 7:38 PM MDT (01:38 UTC)
Expired
Jul 3, 2015, 8:10 PM MDT
In force
32 min
Issued by
NWS Cheyenne, WY
Area
Storm-based polygon
Hail
1.75 in
Wind
60.0 mph

County Converse County, WY

The radar

The Cheyenne radar (KCYS), 210 km from the middle of the area, began a volume at 01:41 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

Denver, CO (KDEN), launched 00:00Z, 1.6 hours before the alert went out and 394 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, Denver, CO at 00:00Z on 2015-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 721 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, Denver, CO at 00:00Z on 2015-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -9 square meters per square second.19395878Sfc1 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
721 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
2055 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
22 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

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 Jul 3, 5:56 PM MDT, 1 hour 42 minutes earlier.

Area forecast discussion, Jul 3, 5:56 PM MDT, 1 hour 42 minutes before
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Hazardous weather outlook, Jul 3, 11:32 AM MDT, 8 hours 6 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
1132 AM MDT FRI JUL 3 2015

NEZ002-003-019>021-054-055-095-096-WYZ101>108-110-114>119-041145-
DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE-
NORTH SIOUX-SOUTH SIOUX-CONVERSE COUNTY LOWER ELEVATIONS-
NIOBRARA COUNTY-NORTH LARAMIE RANGE-
FERRIS/SEMINOE/SHIRLEY MOUNTAINS-SHIRLEY BASIN-
CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY-
EAST PLATTE COUNTY-GOSHEN COUNTY-NORTH SNOWY RANGE FOOTHILLS-
SNOWY RANGE-LARAMIE VALLEY-SOUTH LARAMIE RANGE-
SOUTH LARAMIE RANGE FOOTHILLS-CENTRAL LARAMIE COUNTY-
EAST LARAMIE COUNTY-
1132 AM MDT FRI JUL 3 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NEBRASKA AND
PORTIONS OF SOUTHEAST WYOMING.

.DAY ONE...TODAY AND TONIGHT

WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON AND CONTINUE INTO THIS EVENING.  A FEW OF THESE
THUNDERSTORMS MAY CONTAIN GUSTY WINDS AND SMALL HAIL.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

AN ISOLATED THUNDERSTORM IS POSSIBLE ON SATURDAY...BUT
THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE ON SUNDAY AND EARLY
NEXT WEEK AS A COLD FRONT MOVES SOUTHWARD ACROSS THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

WYZ109-111>113-041145-
CENTRAL CARBON COUNTY-SOUTHWEST CARBON COUNTY-SIERRA MADRE RANGE-
UPPER NORTH PLATTE RIVER BASIN-
1132 AM MDT FRI JUL 3 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
WYOMING...MAINLY THE LOWER ELEVATIONS OF CARBON COUNTY.

.DAY ONE...TODAY AND TONIGHT

A STRAY THUNDERSTORM OR TWO IS POSSIBLE THIS AFTERNOON.
OTHERWISE...NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

AN ISOLATED THUNDERSTORM IS POSSIBLE ON SATURDAY...BUT
THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE ON SUNDAY AND EARLY
NEXT WEEK AS A COLD FRONT MOVES SOUTHWARD ACROSS THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

In the hours before

Local storm report, Jul 3, 6:12 PM MDT, 1 hour 26 minutes before
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Special weather statement, Jul 3, 6:15 PM MDT, 1 hour 23 minutes before
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Special weather statement, Jul 3, 6:39 PM MDT, 59 minutes before
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Special weather statement, Jul 3, 6:50 PM MDT, 48 minutes before
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Local storm report, Jul 3, 7:13 PM MDT, 25 minutes before
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Special weather statement, Jul 3, 7:33 PM MDT, 5 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 3, 6:15 PM MDTSpecial Weather StatementCYS45 min
Jul 3, 6:39 PM MDTSpecial Weather StatementCYSConverse66 min
Jul 3, 6:50 PM MDTSpecial Weather StatementCYSPlatte55 min
Jul 3, 7:33 PM MDTSpecial Weather StatementCYSConverse57 min
Jul 4, 12:56 PM MDTSpecial Weather StatementCYSPlatte49 min
Jul 4, 3:42 PM MDTSpecial Weather StatementCYSLaramie48 min
Jul 4, 3:21 PM MDTSpecial Weather StatementCYSBox Butte39 min
Jul 4, 3:40 PM MDTSpecial Weather StatementCYSSioux35 min
Jul 4, 3:49 PM MDTSevere Thunderstorm WarningCYSBox Butte, Dawes, Sioux56 min
Jul 4, 4:45 PM MDTSpecial Weather StatementCYSSioux30 min
Jul 4, 5:13 PM MDTSpecial Weather StatementCYSBox Butte32 min
Jul 4, 5:32 PM MDTSpecial Weather StatementCYSScotts Bluff28 min
Jul 4, 5:51 PM MDTSevere Thunderstorm WarningCYSMorrill, Scotts Bluff, Sioux39 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2015Every severe thunderstorm warning in 2015

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.