Alert archive / Wyoming / Special Weather Statements in 2021

Special Weather Statement, NWS Cheyenne, WY

July 9, 2021Laramie County, Wyoming

NWS Cheyenne, WY issued this special weather statement at Jul 9, 2021, 1:31 PM MDT for Laramie County, Wyoming. It was in force for 29 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
Jul 9, 2021, 1:31 PM MDT (19:31 UTC)
Expired
Jul 9, 2021, 2:00 PM MDT
In force
29 min
Issued by
NWS Cheyenne, WY

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 5 km from the middle of the area, began a volume at 19:34 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 (KDNR), launched 12:00Z, 7.5 hours before the alert went out and 194 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 12:00Z on 2021-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 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 12:00Z on 2021-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 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
5 J/kg
Mixed-layer CIN
-346 J/kg
Mixed-layer LCL
3383 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
50 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 Jul 9, 11:50 AM MDT, 1 hour 41 minutes earlier.

Area forecast discussion, Jul 9, 11:50 AM MDT, 1 hour 41 minutes before
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<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <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.
      </p>
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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, Jul 9, 4:43 AM MDT, 8 hours 48 minutes before
Hazardous Weather Outlook
National Weather Service Cheyenne WY
443 AM MDT Fri Jul 9 2021

NEZ002-003-019>021-054-055-095-096-WYZ101-102-107-108-119-101045-
Dawes County-Box Butte County-Scotts Bluff County-Banner County-
Morrill County-Kimball County-Cheyenne County-
Northern Sioux County-Southern Sioux County-
Converse County Lower Elevations-Niobrara County-
East Platte County-Goshen County-East Laramie County-
443 AM MDT Fri Jul 9 2021

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

.DAY ONE...TODAY AND TONIGHT

SPC has issued a Marginal to Slight Risk for severe thunderstorms.
Scattered to numerous showers and thunderstorms this afternoon
into overnight hours with some thunderstorms being strong to
severe with gusty, erratic winds, large hail, and heavy rainfall.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

The probability for hazardous weather is low.

.Spotter information statement...

Spotter activation may be needed.

WYZ105-111-112-114-115-101045-
Shirley Basin-Southwest Carbon County-Sierra Madre Range-
Snowy Range-Laramie Valley-
443 AM MDT Fri Jul 9 2021

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

.DAY ONE...TODAY AND TONIGHT

Elevated fire weather concerns through the afternoon for low
humidity and gusty winds.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

The probability for hazardous weather is low.

.Spotter information statement...

Spotter activation will not be needed.

WYZ104-109-110-113-101045-
Ferris/Seminoe/Shirley Mountains-Central Carbon County-
North Snowy Range Foothills-Upper North Platte River Basin-
443 AM MDT Fri Jul 9 2021

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

.DAY ONE...TODAY AND TONIGHT

Red Flag Warning in effect Friday from 11 AM MDT to 8 PM MDT for
gusty winds and low humidity.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

The probability for hazardous weather is low.

.Spotter information statement...

Spotter activation will not be needed.

WYZ103-106-116>118-101045-
North Laramie Range-
Central Laramie Range and Southwest Platte County-
South Laramie Range-South Laramie Range Foothills-
Central Laramie County-
443 AM MDT Fri Jul 9 2021

This hazardous weather outlook is for portions of southeast
Wyoming.

.DAY ONE...TODAY AND TONIGHT

Isolated to scattered showers and thunderstorms this afternoon.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

The probability for hazardous weather is low.

.Spotter information statement...

Spotter activation will not be needed.

In the hours before

Special weather statement, Jul 9, 1:31 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Cheyenne WY
131 PM MDT Fri Jul 9 2021

WYZ117>119-092000-
Central Laramie County WY-South Laramie Range Foothills WY-
East Laramie County WY-
131 PM MDT Fri Jul 9 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN LARAMIE COUNTY UNTIL
200 PM MDT...

At 130 PM MDT, Doppler radar was tracking a strong thunderstorm near
Warren AFB, or 9 miles west of Cheyenne, moving east at 40 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Cheyenne, South Greeley, Hillsdale, Ranchettes, Warren AFB, Frontier
Park, North Cheyenne, Warren Af Base, Fox Farm-College and South
Greeley High.

This includes the following highways...
 Interstate 25 in Wyoming between mile markers 2 and 18.
 Interstate 80 in Wyoming between mile markers 348 and 380.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Cheyenne.

&&

LAT...LON 4109 10508 4126 10505 4125 10444 4100 10451
      4100 10483
TIME...MOT...LOC 1930Z 277DEG 35KT 4117 10497

Hammer

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 1:58 PM MDTSpecial Weather StatementCYSLaramie32 min
Jul 9, 2:20 PM MDTSevere Thunderstorm WarningCYSLaramie40 min
Jul 9, 2:29 PM MDTSpecial Weather StatementCYSLaramie31 min
Jul 9, 2:51 PM MDTSevere Thunderstorm WarningCYSLaramie39 min
Jul 9, 2:58 PM MDTSevere Thunderstorm WarningCYSBanner, Cheyenne, Kimball, Morrill47 min
Jul 9, 3:32 PM MDTSpecial Weather StatementCYSSioux28 min
Jul 9, 3:37 PM MDTSevere Thunderstorm WarningCYSCheyenne, Kimball42 min
Jul 9, 3:54 PM MDTSevere Thunderstorm WarningCYSDawes, Sioux36 min
Jul 9, 4:30 PM MDTSevere Thunderstorm WarningCYSBox Butte, Dawes, Sioux45 min
Jul 9, 5:08 PM MDTSevere Thunderstorm WarningCYSBox Butte, Dawes52 min
Jul 9, 5:42 PM MDTTornado WarningCYSBox Butte33 min
Jul 9, 5:49 PM MDTAreal Flood AdvisoryCYSBox Butte, Morrill3 hr
Jul 9, 5:58 PM MDTSevere Thunderstorm WarningCYSBox Butte, Morrill47 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.