Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 16, NWS Riverton, WY
NWS Riverton, WY issued this severe thunderstorm warning at Aug 21, 2021, 9:11 PM MDT for Sublette County, Sweetwater County, Wyoming. It was in force for 34 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
- Aug 21, 2021, 9:11 PM MDT (03:11 UTC)
- Expired
- Aug 21, 2021, 9:45 PM MDT
- In force
- 34 min
- Issued by
- NWS Riverton, WY
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 50.0 mph
Counties Sublette County, WY, Sweetwater County, WY
The radar
The Riverton/Lander radar (KRIW), 98 km from the middle of the area, began a volume at 03:12 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, 3.2 hours before the alert went out and 102 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
- 53 J/kg
- Mixed-layer CIN
- -86 J/kg
- Mixed-layer LCL
- 2263 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- 156 m²/s²
- 0-3 km storm-relative helicity
- 275 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
339
WUUS55 KRIW 220311
SVRRIW
WYC035-037-220345-
/O.NEW.KRIW.SV.W.0016.210822T0311Z-210822T0345Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Riverton WY
911 PM MDT Sat Aug 21 2021
The National Weather Service in Riverton has issued a
* Severe Thunderstorm Warning for...
Southeastern Sublette County in west central Wyoming...
North central Sweetwater County in south central Wyoming...
* Until 945 PM MDT.
* At 911 PM MDT, a severe thunderstorm was located 9 miles northwest
of Farson, moving northeast at 45 mph.
HAZARD...Quarter size hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.
* This severe thunderstorm will be near...
Big Sandy Recreational Area around 925 PM MDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.
&&
LAT...LON 4233 10953 4264 10908 4259 10907 4244 10907
4243 10904 4226 10905 4226 10898 4214 10895
4209 10941
TIME...MOT...LOC 0311Z 244DEG 40KT 4218 10960
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH
$$
Fisher2 follow-up statements
370
WWUS55 KRIW 220328
SVSRIW
Severe Weather Statement
National Weather Service Riverton WY
928 PM MDT Sat Aug 21 2021
WYC037-220337-
/O.CAN.KRIW.SV.W.0016.000000T0000Z-210822T0345Z/
Sweetwater-
928 PM MDT Sat Aug 21 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL SWEETWATER
COUNTY IS CANCELLED...
The severe thunderstorm which prompted the warning has moved out of
the warned area. Therefore, the warning has been cancelled.
LAT...LON 4264 10908 4259 10907 4243 10907 4243 10904
4226 10905 4226 10925 4244 10937
TIME...MOT...LOC 0327Z 228DEG 44KT 4232 10919
$$
WYC035-220345-
/O.CON.KRIW.SV.W.0016.000000T0000Z-210822T0345Z/
Sublette-
928 PM MDT Sat Aug 21 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 945 PM MDT
FOR SOUTHEASTERN SUBLETTE COUNTY...
At 927 PM MDT, a severe thunderstorm was located 13 miles east of Big
Sandy Recreational Area, or 19 miles northeast of Farson, moving
northeast at 50 mph.
HAZARD...Half dollar size hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.
This severe thunderstorm will remain over mainly rural areas of
southeastern Sublette County.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
&&
LAT...LON 4264 10908 4259 10907 4243 10907 4243 10904
4226 10905 4226 10925 4244 10937
TIME...MOT...LOC 0327Z 228DEG 44KT 4232 10919
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH
$$
Fisher441
WWUS55 KRIW 220339
SVSRIW
Severe Weather Statement
National Weather Service Riverton WY
939 PM MDT Sat Aug 21 2021
WYC035-220348-
/O.EXP.KRIW.SV.W.0016.000000T0000Z-210822T0345Z/
Sublette-
939 PM MDT Sat Aug 21 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN SUBLETTE COUNTY
WILL EXPIRE AT 945 PM MDT...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However small hail
is still possible with this thunderstorm.
LAT...LON 4264 10908 4259 10907 4243 10907 4243 10904
4226 10905 4226 10925 4244 10937
TIME...MOT...LOC 0338Z 244DEG 40KT 4237 10904
$$
FisherThe office that day
Everything else NWS Riverton, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 7:14 PM MDT | Special Weather Statement | RIW | Lincoln | 31 min |
| Aug 21, 7:45 PM MDT | Special Weather Statement | RIW | Lincoln | 30 min |
| Aug 21, 8:24 PM MDT | Special Weather Statement | RIW | 36 min | |
| Aug 21, 8:51 PM MDT | Special Weather Statement | RIW | 24 min | |
| Aug 21, 9:42 PM MDT | Special Weather Statement | RIW | 33 min | |
| Aug 21, 10:06 PM MDT | Special Weather Statement | RIW | Fremont | 24 min |
| Aug 21, 10:30 PM MDT | Special Weather Statement | RIW | Fremont | 30 min |
| Aug 21, 10:36 PM MDT | Special Weather Statement | RIW | Hot Springs | 24 min |
| Aug 21, 10:59 PM MDT | Special Weather Statement | RIW | Washakie | 31 min |
| Aug 21, 11:03 PM MDT | Special Weather Statement | RIW | 27 min | |
| Aug 21, 11:42 PM MDT | Special Weather Statement | RIW | Natrona | 33 min |
| Aug 22, 12:38 PM MDT | Red Flag Warning | RIW | Fremont, Hot Springs, Johnson, Natrona, Sweetwater, Washakie | 31 hr |
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.