Alert archive / Nebraska / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 140, NWS Cheyenne, WY

August 11, 2020Dawes County, Nebraska

NWS Cheyenne, WY issued this severe thunderstorm warning at Aug 11, 2020, 3:52 PM MDT for Dawes 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 counties it named.

The facts

Issued
Aug 11, 2020, 3:52 PM MDT (21:52 UTC)
Expired
Aug 11, 2020, 4:30 PM MDT
In force
38 min
Issued by
NWS Cheyenne, WY
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Dawes County, NE

The radar

The Rapid City radar (KUDX), 158 km from the middle of the area, began a volume at 21:53 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, 9.9 hours before the alert went out and 152 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, Rapid City, SD at 12:00Z on 2020-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 619 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, Rapid City, SD at 12:00Z on 2020-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -10 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
619 J/kg
Mixed-layer CIN
-348 J/kg
Mixed-layer LCL
2036 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
-10 m²/s²
0-3 km storm-relative helicity
53 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

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 Aug 11, 2:22 PM MDT, 1 hour 30 minutes earlier.

Area forecast discussion, Aug 11, 2:22 PM MDT, 1 hour 30 minutes before
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Hazardous weather outlook, Aug 11, 11:00 AM MDT, 4 hours 52 minutes before
Hazardous Weather Outlook
National Weather Service Cheyenne WY
1100 AM MDT Tue Aug 11 2020

WYZ101>105-109>115-121700-
Converse County Lower Elevations-Niobrara County-
North Laramie Range-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-
1100 AM MDT Tue Aug 11 2020

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

.DAY ONE...TODAY AND TONIGHT

Warm, dry and breezy conditions will develop across western
Niobrara, Converse, Albany and Carbon Counties today. A Red Flag
Warning is in effect until 8 PM this evening.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Warm, dry and windy weather will continue each day for areas along
and west of the Laramie Range. A Fire Weather Watch is in effect
Wednesday.

.Spotter information statement...

Spotter activation will not be required.

NEZ002-003-019>021-054-055-095-096-WYZ106>108-116>119-121700-
Dawes-Box Butte-Scotts Bluff County-Banner County-Morrill-
Kimball County-Cheyenne-North Sioux-South Sioux-
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-
1100 AM MDT Tue Aug 11 2020

This hazardous weather outlook is for the western Nebraska
Panhandle and southeast Wyoming.

.DAY ONE...TODAY AND TONIGHT

Isolated to widely scattered thunderstorms will develop along the
Laramie Range early this afternoon and move east into the western
Nebraska Panhandle through early evening. A few of the storms are
expected to become severe with damaging downburst winds and large
hail across the Panhandle.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Warm, dry and windy conditions are expected Thursday across the
southeast Wyoming plains and western Nebraska Panhandle. Critical
fire weather conditions will be possible late Thursday morning
through the afternoon.

.Spotter information statement...

Spotter activation may be required across the western Nebraska
Panhandle from 4 PM through 8 PM this evening.

In the hours before

Special weather statement, Aug 11, 2:58 PM MDT, 54 minutes before
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Special weather statement, Aug 11, 3:11 PM MDT, 41 minutes before
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Special weather statement, Aug 11, 3:17 PM MDT, 35 minutes before
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Special weather statement, Aug 11, 3:34 PM MDT, 18 minutes before
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Special weather statement, Aug 11, 3:35 PM MDT, 17 minutes before
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Special weather statement, Aug 11, 3:44 PM MDT, 8 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 2:08 AM MDTFire Weather WatchCYS11 hr
Aug 11, 1:16 PM MDTSpecial Weather StatementCYSLaramie44 min
Aug 11, 1:20 PM MDTRed Flag WarningCYS31 hr
Aug 11, 5:11 PM MDTSpecial Weather StatementCYS49 min
Aug 11, 2:21 PM MDTSpecial Weather StatementCYSSioux39 min
Aug 11, 2:58 PM MDTSpecial Weather StatementCYSDawes47 min
Aug 11, 3:11 PM MDTSpecial Weather StatementCYSKimball34 min
Aug 11, 3:17 PM MDTSpecial Weather StatementCYSMorrill43 min
Aug 11, 3:34 PM MDTSpecial Weather StatementCYSDawes41 min
Aug 11, 3:35 PM MDTSpecial Weather StatementCYSBox Butte40 min
Aug 11, 4:12 PM MDTSpecial Weather StatementCYSBox Butte48 min
Aug 11, 4:20 PM MDTSpecial Weather StatementCYSDeuel40 min
Aug 11, 4:23 PM MDTSpecial Weather StatementCYSBox Butte52 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 2020Every severe thunderstorm warning in 2020

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.