Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 20, NWS Riverton, WY
NWS Riverton, WY issued this severe thunderstorm warning at Sep 10, 2021, 6:01 PM MDT for 4 counties in Wyoming. It was in force for 44 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
- Sep 10, 2021, 6:01 PM MDT (00:01 UTC)
- Expired
- Sep 10, 2021, 6:45 PM MDT
- In force
- 44 min
- Issued by
- NWS Riverton, WY
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Fremont County, WY, Hot Springs County, WY, Natrona County, WY, Washakie County, WY
The radar
The Riverton/Lander radar (KRIW), 75 km from the middle of the area, began a volume at 00:00 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 00:00Z, 0.0 hours before the alert went out and 69 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.
- Mixed-layer CAPE
- 161 J/kg
- Mixed-layer CIN
- -10 J/kg
- Mixed-layer LCL
- 3637 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 105 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
023 WUUS55 KRIW 110001 SVRRIW WYC013-017-025-043-110045- /O.NEW.KRIW.SV.W.0020.210911T0001Z-210911T0045Z/ BULLETIN - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Warning National Weather Service Riverton WY 601 PM MDT Fri Sep 10 2021 The National Weather Service in Riverton has issued a * Severe Thunderstorm Warning for... Southeastern Hot Springs County in central Wyoming... Northwestern Natrona County in central Wyoming... East central Fremont County in central Wyoming... Southeastern Washakie County in central Wyoming... * Until 645 PM MDT. * At 559 PM MDT, an outflow boundary with severe winds was located along a line extending from 9 miles northeast of Boysen State Park to 15 miles southwest of Moneta, moving east at 40 mph. HAZARD...60 mph wind gusts. SOURCE...Radar indicated. IMPACT...Expect damage to roofs, siding, and trees. * Locations impacted include... Moneta, Cottonwood Pass and Hiland. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. To report severe weather, contact your nearest law enforcement agency. They will send your report to the National Weather Service office in Riverton. Wind damage with these storms will occur before any rain or lightning. Do not wait for the sound of thunder before taking cover. SEEK SHELTER IMMEDIATELY inside a sturdy structure and stay away from windows. && LAT...LON 4367 10740 4300 10723 4292 10799 4345 10814 TIME...MOT...LOC 2359Z 254DEG 33KT 4340 10805 4301 10795 HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...<.75 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...60 MPH $$ TL
3 follow-up statements
093 WWUS55 KRIW 110018 SVSRIW Severe Weather Statement National Weather Service Riverton WY 618 PM MDT Fri Sep 10 2021 WYC013-017-025-043-110045- /O.CON.KRIW.SV.W.0020.000000T0000Z-210911T0045Z/ Hot Springs-Natrona-Fremont-Washakie- 618 PM MDT Fri Sep 10 2021 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM MDT FOR SOUTHEASTERN HOT SPRINGS...NORTHWESTERN NATRONA...EAST CENTRAL FREMONT AND SOUTHEASTERN WASHAKIE COUNTIES... At 617 PM MDT, an outflow boundary with severe winds was located along a line extending from 15 miles northwest of Lysite to 9 miles southwest of Moneta, moving east at 40 mph. HAZARD...60 mph wind gusts. SOURCE...Radar indicated. IMPACT...Expect damage to roofs, siding, and trees. Locations impacted include... Lysite, Moneta, Hiland, Lost Cabin and Cottonwood Pass. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. To report severe weather contact your nearest law enforcement agency. They will send your report to the National Weather Service office in Riverton. Wind damage with these storms will occur before any rain or lightning. Do not wait for the sound of thunder before taking cover. SEEK SHELTER IMMEDIATELY inside a sturdy structure and stay away from windows. && LAT...LON 4367 10740 4300 10723 4293 10792 4350 10798 TIME...MOT...LOC 0017Z 254DEG 33KT 4343 10790 4304 10780 HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...<.75 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...60 MPH $$ TL
598 WWUS55 KRIW 110031 SVSRIW Severe Weather Statement National Weather Service Riverton WY 631 PM MDT Fri Sep 10 2021 WYC013-017-025-043-110045- /O.CON.KRIW.SV.W.0020.000000T0000Z-210911T0045Z/ Hot Springs-Natrona-Fremont-Washakie- 631 PM MDT Fri Sep 10 2021 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM MDT FOR SOUTHEASTERN HOT SPRINGS...NORTHWESTERN NATRONA...EAST CENTRAL FREMONT AND SOUTHEASTERN WASHAKIE COUNTIES... At 631 PM MDT, an outflow boundary with severe winds was located along a line extending from 9 miles west of Cottonwood Pass to 7 miles southeast of Moneta, moving east at 40 mph. HAZARD...60 mph wind gusts. SOURCE...Radar indicated. IMPACT...Expect damage to roofs, siding, and trees. Locations impacted include... Lysite, Moneta, Hiland, Lost Cabin and Cottonwood Pass. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. To report severe weather contact your nearest law enforcement agency. They will send your report to the National Weather Service office in Riverton. Wind damage with these storms will occur before any rain or lightning. Do not wait for the sound of thunder before taking cover. SEEK SHELTER IMMEDIATELY inside a sturdy structure and stay away from windows. && LAT...LON 4367 10740 4300 10723 4294 10781 4353 10788 TIME...MOT...LOC 0031Z 254DEG 33KT 4346 10777 4307 10767 HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...<.75 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...60 MPH $$ TL
382
WWUS55 KRIW 110040
SVSRIW
Severe Weather Statement
National Weather Service Riverton WY
640 PM MDT Fri Sep 10 2021
WYC013-017-025-043-110050-
/O.EXP.KRIW.SV.W.0020.000000T0000Z-210911T0045Z/
Hot Springs-Natrona-Fremont-Washakie-
640 PM MDT Fri Sep 10 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN HOT SPRINGS...
NORTHWESTERN NATRONA...EAST CENTRAL FREMONT AND SOUTHEASTERN WASHAKIE
COUNTIES WILL EXPIRE AT 645 PM MDT...
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However gusty
winds are still possible with these thunderstorms.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Riverton.
LAT...LON 4367 10740 4300 10723 4294 10781 4353 10788
TIME...MOT...LOC 0040Z 254DEG 33KT 4348 10767 4309 10758
$$
TLThe office that day
Everything else NWS Riverton, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 10, 6:44 PM MDT | Special Weather Statement | RIW | Natrona | 31 min |
| Sep 10, 7:15 PM MDT | Special Weather Statement | RIW | Natrona | 30 min |
| Sep 10, 8:03 PM MDT | Special Weather Statement | RIW | Lincoln | 27 min |
| Sep 11, 1:49 PM MDT | Special Weather Statement | RIW | Natrona | 26 min |
Nearby
Severe Thunderstorm Warnings in Wyoming, 2021Every severe thunderstorm warning 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.