Alert archive / Wyoming / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 64, NWS Riverton, WY

July 12, 2019Fremont County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jul 12, 2019, 2:47 PM MDT for Fremont County, Wyoming. It was in force for 21 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 12, 2019, 2:47 PM MDT (20:47 UTC)
Expired
Jul 12, 2019, 3:08 PM MDT
In force
21 min
Issued by
NWS Riverton, WY
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Fremont County, WY

The radar

The Riverton/Lander radar (KRIW), 13 km from the middle of the area, began a volume at 20:50 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, 8.8 hours before the alert went out and 19 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 2019-07-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 37 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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 2019-07-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 square meters per square second.1939Sfc1 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
37 J/kg
Mixed-layer CIN
-306 J/kg
Mixed-layer LCL
2577 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 Riverton, WY wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 12, 11:30 AM MDT, 3 hours 17 minutes earlier.

Area forecast discussion, Jul 12, 11:30 AM MDT, 3 hours 17 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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Hazardous weather outlook, Jul 12, 4:43 AM MDT, 10 hours 4 minutes before
Hazardous Weather Outlook
National Weather Service Riverton WY
443 AM MDT Fri Jul 12 2019

WYZ001>020-022>030-131045-
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-
443 AM MDT Fri Jul 12 2019

This Hazardous Weather Outlook is for Western and Central
Wyoming.

.DAY ONE...Today and Tonight.

Scattered afternoon thunderstorms are expected across northern
Wyoming. Strong and gusty winds are expected near thunderstorms.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Isolated to widely scattered thunderstorms are possible each
afternoon Saturday through Tuesday.

Elevated fire weather concerns are possible on Wednesday and
Thursday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

In the hours before

Special weather statement, Jul 12, 2:13 PM MDT, 34 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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>
Special weather statement, Jul 12, 2:27 PM MDT, 20 minutes before
Special Weather Statement
National Weather Service Riverton WY
227 PM MDT Fri Jul 12 2019

WYZ023>026-122100-
Star Valley-Upper Green River Basin-Upper Green River Basin
Foothills-Salt River and Wyoming Ranges-
227 PM MDT Fri Jul 12 2019

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL SUBLETTE AND
NORTHWESTERN LINCOLN COUNTIES UNTIL 300 PM MDT...

At 226 PM MDT, Doppler radar was tracking a strong thunderstorm near
Turnerville, which is 9 miles northeast of Afton, moving northeast at
55 mph.

Pea size hail and winds in excess of 30 mph will be possible with
this storm.

This strong thunderstorm will be near...
  Meadow Creek Guard Station and Lander Peak around 235 PM MDT.
  Merna around 255 PM MDT.

Other locations impacted by this storm include Bedford.

LAT...LON 4268 11081 4288 11101 4318 11031 4285 11003
TIME...MOT...LOC 2026Z 240DEG 49KT 4281 11078

Swanson
Special weather statement, Jul 12, 2:38 PM MDT, 9 minutes before
Special Weather Statement
National Weather Service Riverton WY
238 PM MDT Fri Jul 12 2019

WYZ017-122100-
Wind River Basin-
238 PM MDT Fri Jul 12 2019

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL FREMONT COUNTY UNTIL 300
PM MDT...

At 237 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles north of Pavillion, moving southeast at 30 mph.

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

This strong thunderstorm will be near...
  Pavillion around 250 PM MDT.

Other locations impacted by this storm include Midvale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

If on or near Morton Lake, Ocean Lake, or Bass Lake, get out of the
water and move indoors or inside a vehicle. Remember, lightning can
strike out to 10 miles from the parent thunderstorm. If you can hear
thunder, you are close enough to be struck by lightning. Move to
safe shelter now! Do not be caught on the water in a thunderstorm.

&&

LAT...LON 4348 10856 4346 10856 4345 10854 4343 10853
      4344 10852 4344 10849 4343 10847 4344 10847
      4345 10844 4341 10824 4311 10852 4334 10895
      4351 10872
TIME...MOT...LOC 2037Z 305DEG 24KT 4337 10871

McDonald
Special weather statement, Jul 12, 2:43 PM MDT, 4 minutes before
Special Weather Statement
National Weather Service Riverton WY
243 PM MDT Fri Jul 12 2019

WYZ005-007-122115-
Owl Creek and Bridger Mountains-Southwest Big Horn Basin-
243 PM MDT Fri Jul 12 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HOT SPRINGS COUNTY
UNTIL 315 PM MDT...

At 242 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles northwest of Thermopolis, moving southeast at 25 mph.

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

This strong thunderstorm will be near...
  Lucerne around 300 PM MDT.
  Thermopolis and Hot Springs State Park around 305 PM MDT.

Other locations impacted by this storm include Hot Springs County
Fairgrounds and Hot Springs County Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

If on or near the Bighorn River, get out of the water and move
indoors or inside a vehicle. Remember, lightning can strike out to
10 miles from the parent thunderstorm. If you can hear thunder, you
are close enough to be struck by lightning. Move to safe shelter
now! Do not be caught on the water in a thunderstorm.

&&

LAT...LON 4371 10852 4384 10839 4368 10791 4346 10812
TIME...MOT...LOC 2042Z 301DEG 21KT 4371 10835

McDonald

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 11, 6:20 PM MDTSpecial Weather StatementRIW25 min
Jul 11, 6:24 PM MDTSpecial Weather StatementRIWFremont21 min
Jul 11, 6:58 PM MDTSpecial Weather StatementRIW47 min
Jul 11, 7:51 PM MDTSpecial Weather StatementRIW39 min
Jul 12, 2:13 PM MDTSpecial Weather StatementRIWHot Springs32 min
Jul 12, 2:27 PM MDTSpecial Weather StatementRIWSublette33 min
Jul 12, 2:38 PM MDTSpecial Weather StatementRIWFremont22 min
Jul 12, 2:43 PM MDTSpecial Weather StatementRIWHot Springs32 min
Jul 12, 3:11 PM MDTSpecial Weather StatementRIWFremont34 min
Jul 12, 3:13 PM MDTSpecial Weather StatementRIWJohnson32 min
Jul 12, 3:16 PM MDTSpecial Weather StatementRIWWashakie29 min
Jul 12, 3:19 PM MDTTornado WarningRIWJohnson26 min
Jul 12, 3:46 PM MDTSpecial Weather StatementRIWJohnson44 min
Jul 12, 3:50 PM MDTSpecial Weather StatementRIWSublette25 min
Jul 12, 3:57 PM MDTSevere Thunderstorm WarningRIWWashakie33 min
Jul 12, 4:04 PM MDTSpecial Weather StatementRIW26 min
Jul 12, 4:16 PM MDTSevere Thunderstorm WarningRIWPark29 min
Jul 12, 4:24 PM MDTSpecial Weather StatementRIWJohnson36 min
Jul 12, 4:29 PM MDTSpecial Weather StatementRIWJohnson31 min
Jul 12, 4:41 PM MDTSpecial Weather StatementRIWBig Horn34 min
Jul 12, 4:47 PM MDTAreal Flood AdvisoryRIWPark3 hr
Jul 12, 5:02 PM MDTSpecial Weather StatementRIWTeton28 min
Jul 12, 5:13 PM MDTSpecial Weather StatementRIWBig Horn32 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2019Every severe thunderstorm warning in 2019

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.