Alert archive / North Dakota / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 771
The Storm Prediction Center issued this severe thunderstorm watch at Aug 12, 2011, 1:47 PM CDT for 19 counties in North Dakota; 13 counties in South Dakota. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 12, 2011, 1:47 PM CDT (18:47 UTC)
- Expired
- Aug 12, 2011, 8:00 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 55 kt
All 32 counties
Barnes County, ND, Benson County, ND, Cass County, ND, Dickey County, ND, Eddy County, ND, Foster County, ND, Grand Forks County, ND, Griggs County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Nelson County, ND, Ramsey County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Steele County, ND, Stutsman County, ND, Traill County, ND, Brown County, SD, Clark County, SD, Codington County, SD, Day County, SD, Deuel County, SD, Edmunds County, SD, Faulk County, SD, Grant County, SD, Hamlin County, SD, Marshall County, SD, McPherson County, SD, Roberts County, SD, Spink County, SD
The radar
The Fargo/Grand Forks radar (KMVX), 129 km from the middle of the area, began a volume at 18:50 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
- 5%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
16 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 12, 1:53 PM CDT | Flash Flood Warning | BIS | Kidder, Stutsman | 5 hr |
| Aug 12, 2:27 PM CDT | Flash Flood Warning | BIS | Foster, Stutsman | 5 hr |
| Aug 12, 2:30 PM CDT | Severe Thunderstorm Warning | FGF | Nelson, Ramsey | 60 min |
| Aug 12, 2:35 PM CDT | Severe Thunderstorm Warning | BIS | Stutsman | 55 min |
| Aug 12, 3:01 PM CDT | Tornado Warning | BIS | Stutsman | 16 min |
| Aug 12, 3:08 PM CDT | Severe Thunderstorm Warning | BIS | LaMoure | 67 min |
| Aug 12, 3:28 PM CDT | Tornado Warning | BIS | Stutsman | 32 min |
| Aug 12, 3:29 PM CDT | Severe Thunderstorm Warning | BIS | Stutsman | 31 min |
| Aug 12, 3:53 PM CDT | Severe Thunderstorm Warning | BIS | Dickey | 45 min |
| Aug 12, 3:57 PM CDT | Severe Thunderstorm Warning | FGF | Griggs, Steele | 48 min |
| Aug 12, 3:59 PM CDT | Tornado Warning | BIS | LaMoure | 31 min |
| Aug 12, 4:19 PM CDT | Severe Thunderstorm Warning | FGF | Barnes, Cass, Ransom | 34 min |
| Aug 12, 4:37 PM CDT | Severe Thunderstorm Warning | FGF | Richland | 53 min |
| Aug 12, 5:02 PM CDT | Severe Thunderstorm Warning | ABR | Marshall | 43 min |
| Aug 12, 5:28 PM CDT | Severe Thunderstorm Warning | FGF | Cass, Traill | 47 min |
| Aug 12, 5:57 PM CDT | Severe Thunderstorm Warning | FGF | Cass | 38 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 11, 7:16 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Bowman, Hettinger, Slope | 4 hr |
| Aug 11, 9:55 PM CDT | Mesoscale Discussion | SPC | Adams, Bowman, Hettinger, Slope | 65 min |
| Aug 12, 1:18 PM CDT | Mesoscale Discussion | SPC | Barnes, Cass, Dickey, Eddy, Foster, Grand Forks and 13 more | 57 min |
| Aug 12, 3:44 PM CDT | Mesoscale Discussion | SPC | Barnes, Benson, Cass, Dickey, Eddy, Foster and 16 more | 91 min |
| Aug 11, 7:19 PM CDT | Severe Thunderstorm Watch | SPC | Bon Homme, Brookings, Charles Mix, Clay, Davison, Douglas and 13 more | 5 hr |
| Aug 11, 9:42 PM CDT | Mesoscale Discussion | SPC | Beadle, Bon Homme, Brookings, Clay, Davison, Douglas and 13 more | 63 min |
Nearby
Severe Thunderstorm Watches in North Dakota, 2011Severe Thunderstorm Watches in South Dakota, 2011Every severe thunderstorm watch in 2011
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.