Alert archive / Wyoming / Special Weather Statements in 2021

Special Weather Statement, NWS Cheyenne, WY

August 15, 2021Platte County, Wyoming

NWS Cheyenne, WY issued this special weather statement at Aug 15, 2021, 1:03 PM MDT for Platte County, Wyoming. It was in force for 42 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 15, 2021, 1:03 PM MDT (19:03 UTC)
Expired
Aug 15, 2021, 1:45 PM MDT
In force
42 min
Issued by
NWS Cheyenne, WY
Hail
0.50 in
Wind
30

County Platte County, WY

The radar

The Cheyenne radar (KCYS), 134 km from the middle of the area, began a volume at 19:03 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

Riverton, WY (KRIW), launched 12:00Z, 7.1 hours before the alert went out and 249 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, Riverton, WY at 12:00Z on 2021-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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, Riverton, WY at 12:00Z on 2021-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2705 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
46 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 15, 11:25 AM MDT, 1 hour 38 minutes earlier.

Area forecast discussion, Aug 15, 11:25 AM MDT, 1 hour 38 minutes before
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  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
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  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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Hazardous weather outlook, Aug 15, 10:58 AM MDT, 2 hours 5 minutes before
Hazardous Weather Outlook
National Weather Service Cheyenne WY
1058 AM MDT Sun Aug 15 2021

NEZ002-019-020-054-095-096-WYZ109-111>114-118-119-161200-
Dawes County-Scotts Bluff County-Banner County-Kimball County-
Northern Sioux County-Southern Sioux County-Central Carbon County-
Southwest Carbon County-Sierra Madre Range-
Upper North Platte River Basin-Snowy Range-Central Laramie County-
East Laramie County-
1058 AM MDT Sun Aug 15 2021

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

.DAY ONE...TODAY AND TONIGHT

Isolated to scattered thunderstorms are expected this afternoon
and evening. A few of the thunderstorms could be strong,
producing small hail and gusty winds.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

Thunderstorm chances will exist most every afternoon and evening,
with the greatest chances on Wednesday, when scattered to numerous
thunderstorms will prevail.

.Spotter information statement...

Spotters are encouraged to report any severe or significant
weather to the National Weather Service in Cheyenne.

WYZ101>108-110-115>117-161200-
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-
Laramie Valley-South Laramie Range-South Laramie Range Foothills-
1058 AM MDT Sun Aug 15 2021

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

.DAY ONE...TODAY AND TONIGHT

Poor air quality expected from 1 PM today through 1 PM MDT Monday.
Those sensitive to poor air quality should plan and limit their
outdoor time accordingly.

Isolated to scattered thunderstorms are expected this afternoon
and evening. A few of the thunderstorms could be strong,
producing small hail and gusty winds.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

Thunderstorm chances will exist most every afternoon and evening,
with the greatest chances on Wednesday, when scattered to numerous
thunderstorms will prevail.

.Spotter information statement...

Spotters are encouraged to report any severe or significant
weather to the National Weather Service in Cheyenne.

NEZ003-021-055-161200-
Box Butte County-Morrill County-Cheyenne County-
1058 AM MDT Sun Aug 15 2021

This hazardous weather outlook is for portions of panhandle
Nebraska.

.DAY ONE...TODAY AND TONIGHT

Isolated to scattered thunderstorms are expected this afternoon
and evening. A few of the thunderstorms could be strong to severe,
producing one inch hail and gusty winds.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

Thunderstorm chances will exist most every afternoon and evening,
with the greatest chances on Wednesday, when scattered to numerous
thunderstorms will prevail.

.Spotter information statement...

Spotters are encouraged to report any severe or significant
weather to the National Weather Service in Cheyenne.

In the hours before

Special weather statement, Aug 15, 1:03 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Cheyenne WY
103 PM MDT Sun Aug 15 2021

WYZ103-105-151945-
Shirley Basin WY-North Laramie Range WY-
103 PM MDT Sun Aug 15 2021

...A strong thunderstorm will impact portions of northeastern Albany
and south central Converse Counties through 145 PM MDT...

At 103 PM MDT, Doppler radar was tracking a strong thunderstorm near
Windy Peak, or 37 miles south of Douglas, moving northeast at 10 mph.

HAZARD...Winds in excess of 30 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...
Friend Park Campground, Windy Peak, Laramie Peak, Garrett and Curtis
Gulch Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

&&

LAT...LON 4205 10550 4210 10587 4242 10578 4238 10532
TIME...MOT...LOC 1903Z 205DEG 8KT 4225 10565

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

Mokry

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 14, 7:01 PM MDTSevere Thunderstorm WarningCYSLaramie44 min
Aug 14, 7:12 PM MDTSevere Thunderstorm Warning Considerable damage threatCYSLaramie48 min
Aug 14, 7:36 PM MDTSevere Thunderstorm WarningCYSLaramie39 min
Aug 15, 12:42 PM MDTAreal Flood AdvisoryCYSAlbany, Carbon3 hr
Aug 15, 1:06 PM MDTAreal Flood AdvisoryCYSAlbany3 hr
Aug 15, 1:42 PM MDTAreal Flood AdvisoryCYSAlbany, Carbon, Converse2 hr
Aug 15, 2:10 PM MDTSpecial Weather StatementCYSAlbany35 min
Aug 15, 2:21 PM MDTSpecial Weather StatementCYSAlbany24 min
Aug 15, 3:47 PM MDTSpecial Weather StatementCYSAlbany28 min
Aug 15, 3:49 PM MDTSpecial Weather StatementCYSAlbany26 min
Aug 15, 4:25 PM MDTSpecial Weather StatementCYSAlbany50 min
Aug 15, 4:46 PM MDTFlash Flood Warning Considerable damage threatCYSAlbany95 min
Aug 14, 6:21 PM MDTSevere Thunderstorm Warning Considerable damage threatCYSBox Butte, Morrill39 min
Aug 14, 6:29 PM MDTSevere Thunderstorm WarningCYSDawes46 min
Aug 14, 7:09 PM MDTSevere Thunderstorm WarningCYSDawes34 min
Aug 14, 7:34 PM MDTSevere Thunderstorm Warning Considerable damage threatCYSCheyenne, Kimball, Morrill41 min

Nearby

Special Weather Statements in Wyoming, 2021Every 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.