Alert archive / Wyoming / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 59, NWS Riverton, WY

July 8, 2019Johnson County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jul 8, 2019, 5:09 PM MDT for Johnson County, Wyoming. It was in force for 51 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 8, 2019, 5:09 PM MDT (23:09 UTC)
Expired
Jul 8, 2019, 6:00 PM MDT
In force
51 min
Issued by
NWS Riverton, WY
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

County Johnson County, WY

The radar

The Riverton/Lander radar (KRIW), 187 km from the middle of the area, began a volume at 23:11 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 8, 1:25 PM MDTSevere Thunderstorm WatchSPC10 hr

The nearest sounding before it

Riverton, WY (KRIW), launched 12:00Z, 11.2 hours before the alert went out and 182 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 2019-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2019-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.1939587897Sfc1 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
3185 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
56 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 8, 5:01 PM MDT, 8 minutes earlier.

Area forecast discussion, Jul 8, 5:01 PM MDT, 8 minutes before
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Hazardous weather outlook, Jul 8, 2:05 PM MDT, 3 hours 4 minutes before
Hazardous Weather Outlook
National Weather Service Riverton WY
205 PM MDT Mon Jul 8 2019

WYZ001>020-022>030-092015-
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-
205 PM MDT Mon Jul 8 2019

This Hazardous Weather Outlook is for Western and Central Wyoming.

.DAY ONE...This afternoon and Tonight.

Scattered thunderstorms through this evening. Some storms could
be severe, especially across the Bighorn Basin to Johnson County
and the surrounding mountains. Large hail, damaging winds and
locally heavy rain will be the primary hazards, but an isolated
tornado could occur.

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

Tuesday...Isolated thunderstorms possible in northern Wyoming.

Friday through Sunday...Isolated to locally scattered
thunderstorms. The best chance will be across the north.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to standard operating procedures.

TEAM RIVERTON

In the hours before

Special weather statement, Jul 8, 3:58 PM MDT, 1 hour 11 minutes before
Special Weather Statement
National Weather Service Riverton WY
358 PM MDT Mon Jul 8 2019

WYZ005-007-017>019-082230-
Owl Creek and Bridger Mountains-Wind River Basin-Green Mountains and
Rattlesnake Range-Southwest Big Horn Basin-Lander Foothills-
358 PM MDT Mon Jul 8 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HOT SPRINGS AND EAST
CENTRAL FREMONT COUNTIES UNTIL 430 PM MDT...

At 357 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 12 miles west of Boysen State Park to 10 miles
southeast of Hudson. Movement was east at 35 mph.

Wind gusts up to 50 mph will be possible with these storms.

Strong thunderstorms will be near...
  Sand Draw around 415 PM MDT.

Other locations impacted by these storms include Arapahoe Elementary
School, Midvale, St Stephens, Bonneville, Riverton Landfill, Fremont
County Fairgrounds and Riverton Regional Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If on or near Boysen Reservoir, 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.

&&

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
central Wyoming.

LAT...LON 4362 10783 4276 10781 4272 10861 4347 10863
TIME...MOT...LOC 2157Z 259DEG 29KT 4340 10843 4283 10841

TL
Special weather statement, Jul 8, 4:02 PM MDT, 1 hour 7 minutes before
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Special weather statement, Jul 8, 4:12 PM MDT, 57 minutes before
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Special weather statement, Jul 8, 4:31 PM MDT, 38 minutes before
Special Weather Statement
National Weather Service Riverton WY
431 PM MDT Mon Jul 8 2019

WYZ005>007-082300-
Owl Creek and Bridger Mountains-Southeast Big Horn Basin-Southwest
Big Horn Basin-
431 PM MDT Mon Jul 8 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HOT SPRINGS AND
CENTRAL WASHAKIE COUNTIES UNTIL 500 PM MDT...

At 430 PM MDT, Doppler radar was tracking a strong thunderstorm over
Lucerne, which is near Thermopolis, moving east at 30 mph.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

This storm will remain over mainly rural areas of southeastern Hot
Springs and central Washakie Counties, including the following
locations... Hot Springs County Fairgrounds and Hot Springs County
Airport.

A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
central Wyoming.

LAT...LON 4354 10824 4373 10848 4393 10764 4365 10753
TIME...MOT...LOC 2230Z 256DEG 28KT 4371 10820

Hulme
Special weather statement, Jul 8, 4:33 PM MDT, 36 minutes before
Special Weather Statement
National Weather Service Riverton WY
433 PM MDT Mon Jul 8 2019

WYZ019-020-082300-
Green Mountains and Rattlesnake Range-Natrona County Lower
Elevations-
433 PM MDT Mon Jul 8 2019

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL NATRONA COUNTY UNTIL
500 PM MDT...

At 432 PM MDT, Doppler radar was tracking a strong thunderstorm near
Ervay, which is 39 miles northeast of Jeffrey City, moving northeast
at 30 mph.

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

This strong thunderstorm will be near...
  Waltman and Waltman Rest Area around 455 PM MDT.
  Powder River around 500 PM MDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4277 10728 4290 10745 4317 10717 4296 10689
TIME...MOT...LOC 2232Z 223DEG 28KT 4288 10729

McDonald
Special weather statement, Jul 8, 4:54 PM MDT, 15 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 7, 6:19 PM MDTSpecial Weather StatementRIWSweetwater26 min
Jul 7, 7:08 PM MDTSpecial Weather StatementRIWSweetwater22 min
Jul 8, 12:46 PM MDTSpecial Weather StatementRIW29 min
Jul 8, 1:08 PM MDTTornado WarningRIWHot Springs, Park37 min
Jul 8, 1:44 PM MDTSevere Thunderstorm WarningRIWBig Horn, Hot Springs, Park46 min
Jul 8, 1:49 PM MDTSpecial Weather StatementRIWTeton26 min
Jul 8, 2:22 PM MDTSpecial Weather StatementRIWPark23 min
Jul 8, 2:27 PM MDTSevere Thunderstorm WarningRIWBig Horn, Park16 min
Jul 8, 2:45 PM MDTSpecial Weather StatementRIWBig Horn30 min
Jul 8, 2:47 PM MDTSpecial Weather StatementRIWPark28 min
Jul 8, 2:56 PM MDTSpecial Weather StatementRIWFremont49 min
Jul 8, 2:57 PM MDTSpecial Weather StatementRIWHot Springs33 min
Jul 8, 3:13 PM MDTSevere Thunderstorm WarningRIWHot Springs, Washakie47 min
Jul 8, 3:28 PM MDTSpecial Weather StatementRIW32 min
Jul 8, 3:29 PM MDTTornado WarningRIWHot Springs, Washakie31 min
Jul 8, 3:32 PM MDTSpecial Weather StatementRIWLincoln28 min
Jul 8, 3:47 PM MDTSpecial Weather StatementRIWHot Springs28 min
Jul 8, 3:48 PM MDTSpecial Weather StatementRIWJohnson27 min
Jul 8, 3:53 PM MDTSevere Thunderstorm WarningRIWBig Horn, Hot Springs, Washakie52 min
Jul 8, 3:58 PM MDTSpecial Weather StatementRIW32 min
Jul 8, 4:02 PM MDTSpecial Weather StatementRIWNatrona28 min
Jul 8, 4:12 PM MDTSpecial Weather StatementRIWHot Springs33 min
Jul 8, 4:26 PM MDTSevere Thunderstorm WarningRIWBig Horn, Hot Springs, Washakie49 min
Jul 8, 4:31 PM MDTSpecial Weather StatementRIWHot Springs, Washakie29 min
Jul 8, 4:33 PM MDTSpecial Weather StatementRIWNatrona27 min
Jul 8, 4:39 PM MDTSevere Thunderstorm WarningRIWBig Horn, Washakie51 min
Jul 8, 4:54 PM MDTSpecial Weather StatementRIWJohnson36 min
Jul 8, 5:16 PM MDTSevere Thunderstorm WarningRIWBig Horn, Johnson44 min
Jul 8, 5:24 PM MDTSpecial Weather StatementRIWBig Horn36 min
Jul 8, 5:33 PM MDTSpecial Weather StatementRIWJohnson27 min
Jul 8, 5:56 PM MDTSpecial Weather StatementRIW34 min
Jul 8, 5:59 PM MDTSevere Thunderstorm WarningRIWJohnson31 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.