Alert archive / Wyoming / Severe Thunderstorm Watches in 2015
Severe Thunderstorm Watch 491
The Storm Prediction Center issued this severe thunderstorm watch at Aug 17, 2015, 2:47 PM MDT for 6 counties in Montana; 14 counties in Wyoming. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 17, 2015, 2:47 PM MDT (20:47 UTC)
- Expired
- Aug 17, 2015, 10:00 PM MDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
Counties Big Horn County, MT, Carbon County, MT, Carter County, MT, Custer County, MT, Powder River County, MT, Rosebud County, MT, Albany County, WY, Big Horn County, WY, Campbell County, WY, Converse County, WY, Crook County, WY, Goshen County, WY, Johnson County, WY, Laramie County, WY, Natrona County, WY, Niobrara County, WY, Platte County, WY, Sheridan County, WY, Washakie County, WY, Weston County, WY
The radar
The Billings radar (KBLX), 212 km from the middle of the area, began a volume at 20:49 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 SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 90%
Warnings issued inside it
11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 2:50 PM MDT | Severe Thunderstorm Warning | BYZ | Carter, Powder River | 55 min |
| Aug 17, 5:32 PM MDT | Severe Thunderstorm Warning | RIW | Natrona | 43 min |
| Aug 17, 6:11 PM MDT | Severe Thunderstorm Warning | RIW | Natrona | 39 min |
| Aug 17, 6:17 PM MDT | Severe Thunderstorm Warning | RIW | Johnson | 43 min |
| Aug 17, 6:22 PM MDT | Severe Thunderstorm Warning | UNR | Campbell | 68 min |
| Aug 17, 6:57 PM MDT | Severe Thunderstorm Warning | RIW | Johnson, Natrona | 48 min |
| Aug 17, 7:00 PM MDT | Severe Thunderstorm Warning | UNR | Campbell | 60 min |
| Aug 17, 7:23 PM MDT | Severe Thunderstorm Warning | CYS | Converse | 52 min |
| Aug 17, 7:30 PM MDT | Severe Thunderstorm Warning | UNR | Campbell, Crook, Weston | 49 min |
| Aug 17, 8:11 PM MDT | Severe Thunderstorm Warning | CYS | Converse, Niobrara | 27 min |
| Aug 17, 8:11 PM MDT | Severe Thunderstorm Warning | CYS | Converse, Niobrara | 49 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 1:10 PM MDT | Mesoscale Discussion | SPC | Big Horn, Carbon, Powder River | 3 hr |
| Aug 17, 1:59 PM MDT | Mesoscale Discussion | SPC | Laramie | 2 hr |
Nearby
Severe Thunderstorm Watches in Wyoming, 2015Severe Thunderstorm Watches in Montana, 2015Every severe thunderstorm watch in 2015
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.