Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 2, NWS Riverton, WY
NWS Riverton, WY issued this severe thunderstorm warning at May 20, 2021, 3:49 PM MDT for Johnson County, Wyoming. It was in force for 29 min. 1 report came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- May 20, 2021, 3:49 PM MDT (21:49 UTC)
- Expired
- May 20, 2021, 4:18 PM MDT
- In force
- 29 min
- Issued by
- NWS Riverton, WY
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
County Johnson County, WY
The radar
The Riverton/Lander radar (KRIW), 230 km from the middle of the area, began a volume at 21:49 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 20, 3:50 PM MDT | HAIL 0.75 | 27 E Buffalo, WY |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Riverton, WY (KRIW), launched 12:00Z, 9.8 hours before the alert went out and 224 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1758 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 167 m²/s²
- 0-3 km storm-relative helicity
- 232 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
047
WUUS55 KRIW 202149
SVRRIW
WYC019-202230-
/O.NEW.KRIW.SV.W.0002.210520T2149Z-210520T2230Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Riverton WY
349 PM MDT Thu May 20 2021
The National Weather Service in Riverton has issued a
* Severe Thunderstorm Warning for...
Northeastern Johnson County in north central Wyoming...
* Until 430 PM MDT.
* At 347 PM MDT, a severe thunderstorm was located near Powder River
Rest Area, or 26 miles southeast of Buffalo, moving north at 30
mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage
to roofs, siding, and trees.
* This severe thunderstorm will remain over mainly rural areas of
northeastern Johnson County.
This includes Interstate 90 between mile markers 77 and 95.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Very heavy rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4408 10613 4414 10641 4456 10627 4456 10601
4423 10602
TIME...MOT...LOC 2147Z 202DEG 27KT 4419 10623
HAIL...1.00IN
WIND...60MPH
$$
VandenBoogart2 follow-up statements
926
WWUS55 KRIW 202203
SVSRIW
Severe Weather Statement
National Weather Service Riverton WY
403 PM MDT Thu May 20 2021
WYC019-202230-
/O.CON.KRIW.SV.W.0002.000000T0000Z-210520T2230Z/
Johnson-
403 PM MDT Thu May 20 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM MDT
FOR NORTHEASTERN JOHNSON COUNTY...
At 401 PM MDT, a severe thunderstorm was located near Powder River
Rest Area, or 27 miles east of Buffalo, moving north at 30 mph.
HAZARD...60 mph wind gusts and nickel size hail.
SOURCE...Radar indicated. At 350 MDT penny-sized hail was reported
10 miles north of I-90 on the Upper Powder River Road.
IMPACT...Expect damage to roofs, siding, and trees.
Locations impacted include...
Powder River Rest Area.
This includes Interstate 90 between mile markers 84 and 93.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4418 10623 4426 10637 4456 10627 4456 10601
4423 10602
TIME...MOT...LOC 2201Z 202DEG 27KT 4429 10617
HAIL...0.88IN
WIND...60MPH
$$
VandenBoogart244
WWUS55 KRIW 202218
SVSRIW
Severe Weather Statement
National Weather Service Riverton WY
418 PM MDT Thu May 20 2021
WYC019-202227-
/O.CAN.KRIW.SV.W.0002.000000T0000Z-210520T2230Z/
Johnson-
418 PM MDT Thu May 20 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN JOHNSON COUNTY IS
CANCELLED...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled. However gusty winds,
frequent lightning, and heavy rain are still possible with this
thunderstorm.
LAT...LON 4418 10623 4426 10637 4456 10627 4456 10601
4423 10602
TIME...MOT...LOC 2216Z 202DEG 27KT 4441 10610
$$
VandenBoogartThe office that day
Everything else NWS Riverton, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 19, 6:15 PM MDT | Special Weather Statement | RIW | 30 min | |
| May 19, 6:17 PM MDT | Special Weather Statement | RIW | 28 min | |
| May 19, 6:20 PM MDT | Special Weather Statement | RIW | Big Horn | 25 min |
| May 19, 6:44 PM MDT | Special Weather Statement | RIW | 31 min | |
| May 19, 7:17 PM MDT | Special Weather Statement | RIW | 28 min | |
| May 19, 7:47 PM MDT | Special Weather Statement | RIW | 28 min | |
| May 19, 9:43 PM MDT | Special Weather Statement | RIW | Johnson | 32 min |
| May 19, 9:58 PM MDT | Special Weather Statement | RIW | Johnson | 32 min |
| May 19, 10:34 PM MDT | Special Weather Statement | RIW | Johnson | 26 min |
| May 19, 11:07 PM MDT | Special Weather Statement | RIW | Johnson | 23 min |
| May 20, 2:23 PM MDT | Special Weather Statement | RIW | Johnson | 22 min |
| May 20, 2:46 PM MDT | Special Weather Statement | RIW | Washakie | 29 min |
| May 20, 2:58 PM MDT | Special Weather Statement | RIW | Johnson | 32 min |
| May 20, 3:16 PM MDT | Severe Thunderstorm Warning | RIW | Johnson | 30 min |
| May 20, 5:22 PM MDT | Special Weather Statement | RIW | Johnson | 23 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.