Alert archive / Wyoming / Special Weather Statements in 2021

Special Weather Statement, NWS Riverton, WY

July 5, 2021

NWS Riverton, WY issued this special weather statement at Jul 5, 2021, 3:26 PM MDT. It was in force for 19 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 5, 2021, 3:26 PM MDT (21:26 UTC)
Expired
Jul 5, 2021, 3:45 PM MDT
In force
19 min
Issued by
NWS Riverton, WY

The radar

The Pocatello radar (KSFX), 156 km from the middle of the area, began a volume at 21:28 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, 9.4 hours before the alert went out and 203 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 2021-07-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 24 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 2021-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 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
24 J/kg
Mixed-layer CIN
-300 J/kg
Mixed-layer LCL
1993 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
36 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

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 Riverton, WY wrote its last area forecast discussion before this special weather statement went out at Jul 5, 2:50 PM MDT, 36 minutes earlier.

Area forecast discussion, Jul 5, 2:50 PM MDT, 36 minutes before
<!doctype html>
<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>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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  </main>
  <script src="index.js"></script>
</body>
</html>
Hazardous weather outlook, Jul 5, 4:49 AM MDT, 10 hours 37 minutes before
Hazardous Weather Outlook
National Weather Service Riverton WY
449 AM MDT Mon Jul 5 2021

WYZ001>020-022>030-061100-
Yellowstone National Park-Absaroka Mountains-Cody Foothills-
North Big Horn Basin-Southwest Big Horn Basin-
Southeast Big Horn Basin-Owl Creek and Bridger Mountains-
Bighorn Mountains West-Bighorn Mountains Southeast-
Northeast Johnson County-Southeast Johnson County-
Teton and Gros Ventre Mountains-Jackson Hole-
Wind River Mountains West-Wind River Mountains East-
Upper Wind River Basin-Wind River Basin-Lander Foothills-
Green Mountains and Rattlesnake Range-
Natrona County Lower Elevations-Casper Mountain-Star Valley-
Salt River and Wyoming Ranges-Upper Green River Basin Foothills-
Upper Green River Basin-South Lincoln County-
Rock Springs and Green River-Flaming Gorge-East Sweetwater County-
449 AM MDT Mon Jul 5 2021

This Hazardous Weather Outlook is for Western and Central
Wyoming.

.DAY ONE...Today and Tonight.

Scattered to numerous showers and thunderstorms are expected this
afternoon and evening, especially across northwest Wyoming. Brief
gusty winds are possible near any showers.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

In the hours before

Special weather statement, Jul 5, 2:04 PM MDT, 1 hour 22 minutes before
Special Weather Statement
National Weather Service Riverton WY
204 PM MDT Mon Jul 5 2021

WYZ012-013-024-052030-
Jackson Hole-Teton and Gros Ventre Mountains-Salt River and Wyoming
Ranges-
204 PM MDT Mon Jul 5 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN LINCOLN AND SOUTH
CENTRAL TETON COUNTIES UNTIL 230 PM MDT...

At 203 PM MDT, Doppler radar was tracking a strong thunderstorm near
Hoback, or 13 miles northeast of Alpine, moving east at 20 mph.

Pea size hail and winds in excess of 40 mph will be possible with
this storm.

This strong thunderstorm will be near...
  Hoback around 220 PM MDT.

Other locations impacted by this storm include Hoback Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Brief heavy rainfall is also occurring with this storm.

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

&&

LAT...LON 4321 11087 4337 11087 4340 11055 4313 11058
TIME...MOT...LOC 2003Z 274DEG 15KT 4328 11082

Vorst
Special weather statement, Jul 5, 2:15 PM MDT, 1 hour 11 minutes before
Special Weather Statement
National Weather Service Riverton WY
215 PM MDT Mon Jul 5 2021

WYZ012-013-052030-
Jackson Hole-Teton and Gros Ventre Mountains-
215 PM MDT Mon Jul 5 2021

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL TETON COUNTY UNTIL
230 PM MDT...

At 215 PM MDT, Doppler radar was tracking a strong thunderstorm over
Moran Junction, moving east at 25 mph.

Pea size hail and winds in excess of 40 mph will be possible with
this storm.

This strong thunderstorm will be near...
  Buffalo Valley Ranch around 225 PM MDT.

Other locations impacted by this storm include Hatchet Campground,
Togwotee Mountain Lodge and Buffalo Ranger Station.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Brief heavy rainfall is also occurring with this storm.

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

&&

LAT...LON 4375 11050 4386 11057 4404 11027 4380 11014
TIME...MOT...LOC 2015Z 248DEG 23KT 4382 11048

Vorst
Special weather statement, Jul 5, 3:26 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Riverton WY
326 PM MDT Mon Jul 5 2021

WYZ023-024-052145-
Star Valley-Salt River and Wyoming Ranges-
326 PM MDT Mon Jul 5 2021

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL LINCOLN COUNTY UNTIL
345 PM MDT...

At 326 PM MDT, Doppler radar was tracking a strong thunderstorm over
Afton, moving east at 25 mph.

Pea size hail and winds in excess of 40 mph will be possible with
this storm.

This strong thunderstorm will be near...
  Corral Creek Guard Station around 345 PM MDT.

Other locations impacted by this storm include Fairview, Afton
Municipal Airport and Lincoln County Fairgrounds.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Brief heavy rainfall is also occurring with this storm.

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

&&

LAT...LON 4263 11097 4276 11102 4290 11067 4267 11058
TIME...MOT...LOC 2126Z 251DEG 20KT 4270 11091

Vorst

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 4, 6:06 PM MDTSpecial Weather StatementRIWPark24 min
Jul 4, 7:47 PM MDTSpecial Weather StatementRIWFremont28 min
Jul 4, 8:19 PM MDTSpecial Weather StatementRIWFremont26 min
Jul 5, 2:04 PM MDTSpecial Weather StatementRIW26 min
Jul 5, 2:15 PM MDTSpecial Weather StatementRIWTeton15 min
Jul 5, 4:58 PM MDTSpecial Weather StatementRIWFremont32 min
Jul 5, 5:14 PM MDTSpecial Weather StatementRIWFremont31 min
Jul 5, 5:25 PM MDTSevere Thunderstorm WarningRIWFremont35 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.