Alert archive / Wyoming / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 93, NWS Riverton, WY

July 26, 2023Fremont County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Jul 26, 2023, 2:41 PM MDT for Fremont County, Wyoming. It was in force for 49 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 26, 2023, 2:41 PM MDT (20:41 UTC)
Expired
Jul 26, 2023, 3:30 PM MDT
In force
49 min
Issued by
NWS Riverton, WY
Area
Storm-based polygon
Hail
0.75 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 20:44 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

Grand Junction, CO (KGJT), launched 12:00Z, 8.7 hours before the alert went out and 435 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, Grand Junction, CO at 12:00Z on 2023-07-26Temperature 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, Grand Junction, CO at 12:00Z on 2023-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 100 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
-325 J/kg
Mixed-layer LCL
2677 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
100 m²/s²
0-3 km storm-relative helicity
130 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 26, 12:23 PM MDT, 2 hours 18 minutes earlier.

Area forecast discussion, Jul 26, 12:23 PM MDT, 2 hours 18 minutes before
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Hazardous weather outlook, Jul 26, 2:43 AM MDT, 11 hours 58 minutes before
Hazardous Weather Outlook
National Weather Service Riverton WY
243 AM MDT Wed Jul 26 2023

WYZ001>020-022>030-271300-
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-
243 AM MDT Wed Jul 26 2023

This Hazardous Weather Outlook is for Western and Central Wyoming.

.DAY ONE...Today and Tonight.

Isolated to widely scattered afternoon and evening showers and
thunderstorms, mainly in the southern half of the area. Strong wind
gusts are the main threat from any storm.

Locally elevated fire weather possible this afternoon.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thursday...Scattered afternoon thunderstorms. Some storms could be
strong to locally severe.

Friday through Sunday...Elevated fire weather possible for much of
the period with hot temperatures, breezy conditions and low humidity.

.SPOTTER INFORMATION STATEMENT...

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

In the hours before

Special weather statement, Jul 26, 1:03 PM MDT, 1 hour 38 minutes before
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Special weather statement, Jul 26, 1:06 PM MDT, 1 hour 35 minutes before
Special Weather Statement
National Weather Service Riverton WY
106 PM MDT Wed Jul 26 2023

WYZ025-026-261930-
Upper Green River Basin-Upper Green River Basin Foothills-
106 PM MDT Wed Jul 26 2023

...Strong thunderstorms will impact portions of south central
Sublette County through 130 PM MDT...

At 105 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 7 miles south of Daniel to 9 miles southwest of
Boulder to 13 miles east of Marbleton. Movement was northeast at 25
mph.

HAZARD...Winds in excess of 40 mph and pea size 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...
  Pinedale, Boulder and Boulder Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

If on or near a 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 4298 10990 4298 10988 4279 10962 4251 10947
      4241 10986 4277 11013
TIME...MOT...LOC 1905Z 233DEG 23KT 4277 11002 4268 10989 4253 10984

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

Myers
Special weather statement, Jul 26, 1:29 PM MDT, 1 hour 12 minutes before
Special Weather Statement
National Weather Service Riverton WY
129 PM MDT Wed Jul 26 2023

WYZ028-029-262000-
Flaming Gorge-Rock Springs and Green River-
129 PM MDT Wed Jul 26 2023

...A strong thunderstorm will impact portions of west central
Sweetwater County through 200 PM MDT...

At 128 PM MDT, Doppler radar was tracking a strong thunderstorm near
Green River, moving northeast at 35 mph.

HAZARD...Winds in excess of 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This strong thunderstorm will be near...
  Green River around 140 PM MDT.

Other locations in the path of this storm include southwestern Rock
Springs.

This includes Interstate 80 between mile markers 86 and 101.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

If on or near Flaming Gorge 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.

&&

LAT...LON 4134 10959 4143 10964 4170 10946 4151 10916
      4146 10918 4144 10924 4141 10924 4132 10950
TIME...MOT...LOC 1928Z 230DEG 29KT 4144 10950

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

Myers
Special weather statement, Jul 26, 1:59 PM MDT, 42 minutes before
Special Weather Statement
National Weather Service Riverton WY
159 PM MDT Wed Jul 26 2023

WYZ015>019-262030-
Wind River Basin-Upper Wind River Basin-Wind River Mountains
East-Green Mountains and Rattlesnake Range-Lander Foothills-
159 PM MDT Wed Jul 26 2023

...Strong thunderstorms will impact portions of central Fremont
County through 230 PM MDT...

At 158 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 10 miles west of Crowheart to Upper Silas Lake.
Movement was east at 40 mph.

HAZARD...Winds in excess of 40 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.

Strong thunderstorms will be near...
  Fiddlers Lake, Upper Silas Lake, Frye Lake, Christina Lake and
  Worthen Meadows Reservoir around 205 PM MDT.
  Louis Lake and Sinks Canyon State Park around 210 PM MDT.

Other locations in the path of these storms include Red Canyon,
Lander, and Diversion Dam Rest Area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Very heavy rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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

These storms 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 Bull Lake and Ray 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.

Persons in campgrounds should consider seeking sturdy shelter until
these storms pass.

&&

LAT...LON 4340 10952 4341 10891 4259 10838 4259 10898
TIME...MOT...LOC 1958Z 276DEG 36KT 4333 10940 4265 10896

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

McDonald
Special weather statement, Jul 26, 2:36 PM MDT, 5 minutes before
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Local storm report, Jul 26, 2:40 PM MDT, 1 minute before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 26, 12:26 PM MDTSpecial Weather StatementRIWSublette34 min
Jul 26, 12:37 PM MDTSpecial Weather StatementRIWSublette23 min
Jul 26, 1:06 PM MDTSpecial Weather StatementRIWSublette24 min
Jul 26, 1:29 PM MDTSpecial Weather StatementRIWSweetwater31 min
Jul 26, 1:59 PM MDTSpecial Weather StatementRIWFremont31 min
Jul 26, 2:26 PM MDTSevere Thunderstorm WarningRIWFremont34 min
Jul 26, 2:36 PM MDTSpecial Weather StatementRIW24 min
Jul 26, 3:12 PM MDTSevere Thunderstorm Warning Considerable damage threatRIWFremont, Hot Springs, Natrona, Washakie48 min
Jul 26, 3:13 PM MDTSpecial Weather StatementRIWSweetwater47 min
Jul 26, 3:19 PM MDTSpecial Weather StatementRIWHot Springs26 min
Jul 26, 3:42 PM MDTSpecial Weather StatementRIW33 min
Jul 26, 3:48 PM MDTSpecial Weather StatementRIWWashakie27 min
Jul 26, 3:55 PM MDTSpecial Weather StatementRIW35 min
Jul 26, 4:00 PM MDTSpecial Weather StatementRIWNatrona30 min
Jul 26, 4:13 PM MDTSpecial Weather StatementRIWNatrona47 min
Jul 26, 4:41 PM MDTSevere Thunderstorm WarningRIWNatrona34 min
Jul 26, 4:45 PM MDTSpecial Weather StatementRIWNatrona30 min
Jul 26, 5:17 PM MDTSpecial Weather StatementRIWNatrona28 min
Jul 26, 5:36 PM MDTSpecial Weather StatementRIWJohnson39 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2023Every severe thunderstorm warning in 2023

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.