Alert archive / Wyoming / Special Weather Statements in 2021
Special Weather Statement, NWS Riverton, WY
NWS Riverton, WY issued this special weather statement at Aug 21, 2021, 10:30 PM MDT for Fremont County, Wyoming. It was in force for 30 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, 10:30 PM MDT (04:30 UTC)
- Expired
- Aug 21, 2021, 11:00 PM MDT
- In force
- 30 min
- Issued by
- NWS Riverton, WY
- Hail
- 0.25 in
- Wind
- 55
County Fremont County, WY
The radar
The Riverton/Lander radar (KRIW), 66 km from the middle of the area, began a volume at 04:31 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, 4.5 hours before the alert went out and 60 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.
769
WWUS85 KRIW 220430
SPSRIW
Special Weather Statement
National Weather Service Riverton WY
1030 PM MDT Sat Aug 21 2021
WYZ005-007-017>019-220500-
Owl Creek and Bridger Mountains-Wind River Basin-Green Mountains and
Rattlesnake Range-Southwest Big Horn Basin-Lander Foothills-
1030 PM MDT Sat Aug 21 2021
...Strong thunderstorms will impact portions of southeastern Hot
Springs, southwestern Natrona and southeastern Fremont Counties
through 1100 PM MDT...
At 1030 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 7 miles west of Boysen State Park to near
Arapahoe to near Sweetwater Station. Movement was northeast at 55
mph.
HAZARD...Wind gusts of 50 to 55 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.
Strong thunderstorms will be near...
Shoshoni around 1040 PM MDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
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.
&&
LAT...LON 4248 10727 4232 10821 4332 10867 4361 10778
4299 10750 4293 10750 4293 10747
TIME...MOT...LOC 0430Z 243DEG 46KT 4329 10833 4290 10842 4255 10824
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH
$$
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, 9:11 PM MDT | Severe Thunderstorm Warning | RIW | Sublette, Sweetwater | 34 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, 10:36 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
Special Weather Statements in Wyoming, 2021Every special weather statement 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.